With a budget of $400 - Rigol or Siglent scope? - Page 1
Forum section: electronics / testgear

author: DougSpindler
author_rank: Super Contributor
timestamp: January 27, 2018, 02:29:11 pm
content: Trying to decide if should buy the DS-1054Z, the SDS1000X-E, or something else? I’m a computer/technology instructor who is teaching a semester long technology (STEM) class to talented high school students. Yesterday I was given a budget to purchase a scope and need to make a purchase decision in a few days.My skill digital electronics skill level is on the order of a hobbiest/tinkerer. (Just looking for a basic scope.). (Not sure if I need four channels.)The class I’m teaching the students is based on Audrino so if the scope has the ability to decode that would be a big+1. (I am teaching students about fames, packets and protocols.)I will never master all of the features of the scope I will be pucchansing is one more intuit that the other?I plan on having student use the scope with their Arduino projects to give them experience using a scope need something they can learn quickl, play around with and not destroy.Not sure if I need four channels. But if it’s four channels vs. packet decoding (UART, SPI) I would favor the decoder.Other pluses with be HDMI output so I could connect to a video projector.LAN port? Is there software which allows remote front pannel controls? WHich would prevent students from breaking the knobs?Does one have a larger display? Or make better use of the screen real estate?Would greatly appreciate your thoughts.(Sorry for the cross post, but I need to make a purchase descesion in about a day.)Thank you very much.

author: nctnico
author_rank: Super Contributor
timestamp: January 27, 2018, 02:38:45 pm
content: Get the Rigol DS1054Z as it seems the Siglent still has bugs in the protocol decoding and the worst thing for a student is equipment which throws them curve balls. A step up are the scopes from GW Instek. These are more expensive but it doesn't hurt to contact GW Instek about educational discounts. It wouldn't surprise me if they can compete (GDS2072E for example) and then you'll have a scope which is more capable compared to the DS1054Z.

author: Hydron
author_rank: Super Contributor
timestamp: January 27, 2018, 02:53:03 pm
content: The 4 channel SDS1x04X-E siglent option has remote screen/controls, none of the other options do. I've never used the Siglent in person, only the Rigol, so I can't comment about the decodes etc.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 27, 2018, 02:55:23 pm
content: Does the Rigol have decoding abilities?This is education. When i say I have a budget of $400 it’s $400. Any more and some administration official won’t get their pay bouns.

author: nctnico
author_rank: Super Contributor
timestamp: January 27, 2018, 03:05:11 pm
content: Quote from: DougSpindler on January 27, 2018, 02:55:23 pmEducation is also the magic word to get discounts so it helps to call around! Getting a Keysight scope might not be out of the realm of possibilities as well. I suppose hacking the scope is out of the question so your choices aren't far apart when it comes to bandwidth.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 27, 2018, 03:16:43 pm
content: No time to call around for ed discounts. My dept chair found some unspent money on Friday that others don’t know about yet. If I can spend fist, I’ve got it. If I have to call around for an ed discount I will lose the funds to someone else. Isn’t education smart?

author: rsjsouza
author_rank: Super Contributor
timestamp: January 27, 2018, 03:27:06 pm
content: One warning: just be sure the free bundle options are still valid on the distributors:https://www.eevblog.com/forum/buysellwanted/rigol-ds1054z-on-sale-$349-with-options-tequipment/If not, make sure your university will not frown upon you "hacking" the oscilloscope to get these options. Also, if you are unable to "hack" it, keep in mind it is only a 50MHz scope.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 27, 2018, 03:40:38 pm
content: So would you suggest I go with the Rigol? I’m teaching “hacking”.... So there’s no problem with me hacking the scope. Other reason to buy “quicK’ is before some buireacrat starts aksing silly questions to delay the purchase.Does the Rigol have the decoding of SPI, serial/UART etc?

author: DougSpindler
author_rank: Super Contributor
timestamp: January 27, 2018, 03:53:06 pm
content: Rigol’s web site says it comes with the software bundle and the lower price of $349.Arrr. Wish Dave would make a video comparing them. Sounds like the Rigol is nearing end of life. But the Siglent is new and has some software bugs. Which one?

author: SkyMaster
author_rank: Frequent Contributor
timestamp: January 27, 2018, 04:29:47 pm
content: Quote from: DougSpindler on January 27, 2018, 03:53:06 pmAt $349, buy the DS1054Z; and you will sleep well at night.

author: Fungus
author_rank: Super Contributor
timestamp: January 27, 2018, 04:36:38 pm
content: Quote from: DougSpindler on January 27, 2018, 03:40:38 pmYes. It's an option but currently every Rigol distributer seems to be offering it for free.If you can't get the special offer then don't worry, all you need to do press the right sequence of buttons on the front panel and it will appear.You can also get 100MHz bandwidth and a bunch of other stuff using the same procedure.As for Rigol vs. Siglent: 4 channels wins IMHO.

author: Mr. Scram
author_rank: Super Contributor
timestamp: January 27, 2018, 04:39:55 pm
content: Quote from: DougSpindler on January 27, 2018, 03:16:43 pmI'm putting this on a tile.

author: rf-loop
author_rank: Super Contributor
timestamp: January 27, 2018, 04:56:20 pm
content: Quote from: DougSpindler on January 27, 2018, 02:55:23 pmBecause this, go to Rigol DS1054Z. It give still lot of educational features including 4 channels with this price (under USD 400 in US).There is others with lot of more power and performance if buidget is not so tight limit and if it can stretch some amount. But, with absolute 400 limit -> this Riglol.

author: Old Printer
author_rank: Frequent Contributor
timestamp: January 27, 2018, 04:56:43 pm
content: Quote from: DougSpindler on January 27, 2018, 03:53:06 pmAll newly released scopes in the low price market will have bugs, the Rigol had/has them depending on who you ask. They take time to get worked out. What used to get done in R&D before release is now put on the user to find, then they fix, maybe. The 1054 is more mature, the new Siglent may have the potential to be a better scope after some firmware fixes that may or may not get done to the users satisfaction. I still like the Analog Discovery for students, considering the extra tools available, let them drag their stuff to your deskbut I get it, I want a "real" scope too

author: rstofer
author_rank: Super Contributor
timestamp: January 27, 2018, 04:57:23 pm
content: Quote from: DougSpindler on January 27, 2018, 03:53:06 pmWhy do you suggest end-of-life? They just got the last of the bugs out a few months back and now it's easy sailing. Rigol absolutely owns the entry level scope market and all they have to do is crank out scopes and rake in cash.Siglent, OTOH, is the new kid in town and there are known firmware issues. The question is: How long until they're fixed? Has anybody heard about a firmware upgrade?Call TEquipment and see what they have to say about the bundle of options. If you let their home page cycle long enough, you will see the offer of free options.https://www.tequipment.net/$348 with $745 in free options.I don't see how you can beat this deal!

author: rstofer
author_rank: Super Contributor
timestamp: January 27, 2018, 05:04:20 pm
content: Quote from: Old Printer on January 27, 2018, 04:56:43 pmI consider the AD to be a bit fragile. I sure wouldn't turn an unsuspecting AD loose on a class full of students.OTOH, I do like the features and, of course, the 27" display. Portability is easily solved with a laptop. In that regard, it is better than a real scope because no power strip is required. This might actually be handy for outdoor robotics projects.For the OPs application, the DS1054Z will be an excellent choice.

author: rsjsouza
author_rank: Super Contributor
timestamp: January 27, 2018, 06:42:17 pm
content: Quote from: DougSpindler on January 27, 2018, 03:40:38 pmIn this case, you can't go wrong with the Rigol, as hacking brings you everything including the higher bandwidth of bandwidth 100MHz.If you couldn't hack or the bundle was not available, the DS1054Z value would be greatly reduced when compared to similar offerings.

author: imidis
author_rank: Frequent Contributor
timestamp: January 27, 2018, 07:32:15 pm
content: Yeah, Rigol

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 02:51:28 am
content: I want to thank each and everyone of you for your advice. Not only did you help me, but you are helping educate the next generation... Who knows one might be a future employee of yours.This is the first time I'm teaching high school studnts. (These kids are smart, really smart.) Expect them to he in the fourms oen day. And I have one 8th grader who is just brilliiant.The outcome of the class is to teach studnets about computers, programmingm, comptuer networking and cyber-secuirty, I found this video on YoutTube whihc is perfect.https://ru-clip.com/video/vXBfwgwT1nQ/arcade-scam-science.htmlThe lesson the guy in the vidoe is teaching high school studnets is perect. Is it morally/legaly acceptatble to "hack" a machine that's cheating you?So starting with the Arduino. Will teach them programing to get the lights to flash in sequence. (Simulate the game.) Then buid the photo-detector circuit. Next they will have to write an smartphone appp and quickly realize if the app is to communicate w8ith the arduino they will need to learn networking. (I hope you find that as clever as I think it is.)Wish me luck. When I showed the video to my studnts they were really excited.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: January 28, 2018, 03:31:35 am
content: Typing a serial number into a keygen on a web page, then entering the resulting unlock code into the scope... is hardly the kind of "hacking" that will actually teach anyone anything about "hacking".

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 04:43:13 am
content: Quote from: alsetalokin4017 on January 28, 2018, 03:31:35 amIt teaches it can be done.Love the Feynman quote.

author: Keysight DanielBogdanoff
author_rank: Unknown
timestamp: January 28, 2018, 06:05:29 am
content: Quote from: DougSpindler on January 27, 2018, 03:16:43 pmKeysight does 15% for education, no haggling needed. Good luck with your new class!

author: TK
author_rank: Super Contributor
timestamp: January 28, 2018, 06:33:51 am
content: Another good option for a classroom scope is the Micsig TO1104. The fully loaded model (4 channels, 100MHz, battery, HDMI, WiFi, serial protocol decode, 500uV, 28Mpts) is around $475 on amazon. You can use the HDMI port to show the scope display on a large LCD TV, monitor or projector.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 07:06:49 am
content: Quote from: Keysight DanielBogdanoff on January 28, 2018, 06:05:29 amThanks for the sugestion. Do you know which model I shouold consider? I've been looking on their web site and it's confusing. Are you recomending the EDUX1002A Oscilloscope: 50 MHz, 2 Analog Channels? Can only find one review and a YouTubeo saying the frame decoder has issues. Why would I want to go with this over the Rigol? Everyone else has said buy the Rigor.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 07:50:52 am
content: Quote from: TK on January 28, 2018, 06:33:51 amThis looks intereting but there are no knobs. It's a touch screen. Horrible for teaching. Studnets and I will point to the screen to discuss something only to find we changed settings. I really like my Windows 10 touch screen comptuer. But using it as a teaching tool is horrible. Drives me and students crazy.

author: abraxa
author_rank: Frequent Contributor
timestamp: January 28, 2018, 08:06:51 am
content: Don't overthink this. You can't go wrong with the Rigol and if I were in your position, I'd make sure to act fast.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 08:20:43 am
content: Quote from: abraxa on January 28, 2018, 08:06:51 am+1 Rigol order is going in now. Way I look at this. I'm driving across the desert. I could drive a Rolls Royce or a Model T ford. If I need assistance (which I'm sure I will), I'd like to be driving something lots of other people will have and know how to fix. Seems like "everyone" has a Rigol.... Easy to someone who will know how to assist me.One feature I really want are the frame/protocol decoders used in Arduino. SPI, RS-232/UART.I can't thank everyone enough for assisting. As Dave would say, "Bob's your uncle" .

author: BravoV
author_rank: Super Contributor
timestamp: January 28, 2018, 08:30:03 am
content: Quote from: DougSpindler on January 28, 2018, 08:20:43 amWise move.Yes, you've identified another hidden value of owning a popular gadget, especially in this electronic tinkerers lair.Cause once these "tons" of owners of this scope's warranty are expired, I believe you will see lots of these "tinkerers" will start to do self repair if its repairable of course, and I'm quite confident these tips/tricks on common problems on this aged scope model will be shared here. This condition is a perfect fits in for hobbyist level or owners with limited budget that can not afford the so called maintenance contract to extend the scope's warranty.My 2 cents worth, and have fun.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 08:43:36 am
content: Quote from: BravoV on January 28, 2018, 08:30:03 amI plan on it. Rigol and "Bob's my uncle" (Do they say that?) I'm in the states and like the Aussie sayings. I know enopugh not to say I'm rooting for Dave.

author: abraxa
author_rank: Frequent Contributor
timestamp: January 28, 2018, 09:17:45 am
content: Quote from: DougSpindler on January 28, 2018, 08:20:43 ambtw, I was going to mention getting a FX2-based logic analyzer since they're so very cheap, however they need to be connected to a laptop - which can be fried if the students push too high a voltage into the device. If you feel confident that this won't happen then I suggest getting one of those as well (and sigrok as the software suite for it). It could be a good way to teach them to use the right tool for the job.

author: Electro Detective
author_rank: Super Contributor
timestamp: January 28, 2018, 09:49:58 am
content: Get a scope that has dedicated controls above the inputs, be it a 2 channel or 4The last thing you need with students hovering aboutis switched/ shared channels BS on a DSO you have to master asap"Who's on first, What's on second, I don't know on third..."

author: djnz
author_rank: Regular Contributor
timestamp: January 28, 2018, 10:59:20 am
content: Quote from: abraxa on January 28, 2018, 09:17:45 amA USB opto-isolator would help here. Perhaps something based on the ADuM4160, likehttps://www.adafruit.com/product/2107

author: rsjsouza
author_rank: Super Contributor
timestamp: January 28, 2018, 01:52:24 pm
content: Quote from: Electro Detective on January 28, 2018, 09:49:58 amIMO I don't see this as a blocking issue. Sure, this can be an annoyance but far from the modern reality - especially when dealing with the fact compact multichannel units are what the students will most probably use after high school is over.If anything, this will give them a taste of reality...

author: TK
author_rank: Super Contributor
timestamp: January 28, 2018, 02:40:32 pm
content: Quote from: DougSpindler on January 28, 2018, 07:50:52 amInteresting perspective, thank you for sharing your experience.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 04:02:08 pm
content: Quote from: Electro Detective on January 28, 2018, 09:49:58 amThanks. But what’s the fellows name? Tomorrow. No, I want to know today. I fpn’y know. Why, third base.Have you ever tried to shut down a Windows Computer. Click on Start. No I want to shut the computer down. I know, click on Start. Why would I click on Start if I want to Shut the computer down? Because.Why I don’t know, (Thisi is on the web somewhere.)Classic and brilliant.I tell my students UDP jokes, but they don’t seem to get it. But TCP jokes they get every time.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 06:07:06 pm
content: Quote from: abraxa on January 28, 2018, 09:17:45 amThanks for the suggestion. I’m not as familiar with a logic analyzer so I watched several of Dave’s videos on LA. This is really helping me get a better understanding the the lower level hardware and components. If you know the OSI model I’m more of a layer 2 - 5 guy.I do have a question. In computer networking/OSI model we have bits, frames and packets. Very precise definitions. But in digital electronics Dave used the term frame when I would consider it a frame.A series of bits are framed into meaning full data by identifying the start/stop bits. I’m thinking maybe in this world a bus is being used so there’s no addressing??? So you folks use frame and packet interchangeable? Or in thinking about this maybe the frame contains the address so frame or packet is really the same thing?Not sure if you are familiar with Wireshark. (I am. It’s a packet decoder.). You are making me realize a logic analyzer is a low level packet decoder which shows shows voltage and timing. Wireshark is sort of doing the same thing but doen’st display the pin voltages.Thanks for making me think, you are making me a much better instructor.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 06:35:58 pm
content: Quote from: rsjsouza on January 28, 2018, 01:52:24 pmSouds like you might not be aware of what’s going on in our educational system. Remember “no child get’s left behind”, that also means “no child gets ahead” either. It’s been years since I was in high school, but I returned to see what it’s like today. I was almost in tears. Gone is wood, metal, auto, drafting and electronic is. Those beautiful shops have all been turned into classroom space. We are expecting students to lean in what looks like a warehouse.And then we teach studnets math and give them no practical application. That’s why we had the shop classes so one could apply the what was learned in a math class to make something studnets could say them made themselves. I still have a treasure many of the items I made in my 7th and 8th grade metal shop class.How times have changed. I’m now a college professor and have been teaching cyber security for the past 15 years. There are very few of us who take the time to learn and teach studnets the latest material. Most of my tenured professors have been teaching the same material in cyber security they were teaching 10-20 years ago. No employer will hire someone for a cyber security or probably and EE job if their education is based on 10 - 20 year old material. Yes it is that bad. Need proof? How many times has your credit card been stolen curtosey of HomeDepot, Target, Hyatt, TJ Max? It’s a long list.The folks running our education system today believe we should be teaching to the “least able student” because that’s what’s “fair”. We want equality in education.I sure as heck don’t. I would like to see students perform to their level of ability and interest.Sorry for the rant..... But yes it is that bad here int he states.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 06:42:02 pm
content: I did loook into the educational discount for Rigol scopes. Price on the Rigol scope is #349. Educational dissouted price is $331 or a savings of $18. Much easer to order from Amazon and get it Tuesday that wait until Monday and source from another vendor. No if we were buying 25-30 scopes different story. I’m only buying one, just not worth it.

author: evgen.05
author_rank: Regular Contributor
timestamp: January 28, 2018, 07:51:40 pm
content: Siglent SDS 1202x-e best price for today. Or 1204- 4 ch. On this day is the best osc. for they price. Not Rigol or somethings else. Rigol is near of the end of life today. lt's obvious. Siglent is fresh decigion. If new products released from Rigol tomorrow - we wll see. But today - Siglent - best scopes today for the price.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 08:29:54 pm
content: Quote from: evgen.05 on January 28, 2018, 07:51:40 pmCan't find pricing or for that matter any information about the product. It would be irresponsible of my to buy a product with tax payer money for an educational instruction without any information other than you saying it has the best price today. I'm looking for what would be the best value for the college and students. Price is only one factor when considering value.Can you direct me to any specs, reviews or edu pricing?

author: tautech
author_rank: Super Contributor
timestamp: January 28, 2018, 08:54:10 pm
content: Quote from: DougSpindler on January 28, 2018, 08:29:54 pmYou didn't look very hard.https://www.siglentamerica.com/digital-oscilloscopes/sds1000x-e-series-super-phosphor-oscilloscopes/Dave's done teardowns on the 2 and 4ch versions.Siglent America is a member here and they also have an Amazon shop.Shoot them an email.

author: imidis
author_rank: Frequent Contributor
timestamp: January 28, 2018, 08:59:11 pm
content: really price wise the 1202x-e is the only viable one for the budget.OP made decision already.

author: abraxa
author_rank: Frequent Contributor
timestamp: January 28, 2018, 09:20:50 pm
content: Quote from: evgen.05 on January 28, 2018, 07:51:40 pmAs far as I can tell, it doesn't seem like he can get a 4-ch Siglent scope for the $400 budget. With 2 channels, doing meaningful SPI decoding is impossible, so for that reason alone I'd go for a 4-ch model - which seems to only leave the Rigol DS1054z.

author: abraxa
author_rank: Frequent Contributor
timestamp: January 28, 2018, 10:06:45 pm
content: Quote from: DougSpindler on January 28, 2018, 06:07:06 pmTo stay within this analogy, logic analyzers begin on OSI level 1 and can go up to any OSI level really, depending on the protocol and the logic analyzer's abilities. Since the variety of physical implementations of all the different protocols are vastly different, what is a frame for one protocol may not be a frame for another. It all really depends on the signal(s) you're looking at, so there's no universal definition.Quote from: DougSpindler on January 28, 2018, 06:07:06 pmYeah, pretty much. You could also say that a scope is designed to look at signals in the analog realm and a LA is made to look at signals in the digital realm. They're different tools for different jobs really. The fact that modern scopes can decode protocols doesn't make them well-suited for analyzing digital systems, it just means that they're able to do it - like driving a screw into a block of wood: just because a hammer is able to do it doesn't mean that it's the right tool for the job. A scope with decode abilities will be fine for your class, just wanted to make you aware.If you have the time and would like to know more, you can check out e.g.shows how stacked decoders are used to make sense of data (here: I2C -> DS1307 and SPI -> SSI32)looks at examining I2C signals with sigrokgives a more complete picture of what sigrok can do, though it's maybe too detailed for you

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 10:19:38 pm
content: Quote from: tautech on January 28, 2018, 08:54:10 pmPlesase don't say I havre not looked very hard, I have.What I found from the link your provided was ...."SIGLENT’s new SDS1000X-E Super Phosphor Oscilloscopes sets a new higher bar in low-cost oscilloscopes. Available in 2 and 4-channel versions (the 4 channel versions include several additional features and options)....."What I can't find is what fetures I'm giving up.I made it very clear I have a $400 budget.Compared to the Rigol I'm giving up two channels. And now I find I'm giving something else up in addition to two channels.Yes I watched Dave's tear down. Did that anwer my original post which explained my needs? NopeI watched several other videos on YouTube but all they did was explain features. There was no comparison with the Rigol or any other scope.In the online revies for the SDS1000X-E there aren't that many. And the ones who provided any detained information admissted they were hiobbiests and were probably not the best qualifed to write a review. I also found someone else who coimmented the decodes feature doesnt' work so well. This is a feature I stated I wanted. So why would I want to buy something that's not going to work?From what I can see the Siglet is newer, has a faster boot time and a math co-processor. The Rigol boots 10 seconds sloer, does all of the sme decodes and has two channles more. ANd the Rigol is less expensive.It appears to get the same funtionality in the Siglent I would have to spend twice the prices.And here's the real kicker... Dave pointed thos out in his teardown.... The caps. Not sure if you are aware but PC poser supplies used the same manufactures cpas. Thosee things failed frequently. I remember having to replacie many of them. So here's I'm paying a premium for a prodcut which may have defectiv caps. As Dave asked, why didn't the compny use "good" caps like Panasonic?So far no one has given me a compelling reaon NOT to buy Rigol based on my crieteia. On the otherhand I have found numerous reasons not to buy Siglent.The order is in, but I have until tomoorw before it will be procssed. If you are anyone can provide a compelling arguement not to buy Rigol and buy Siglent I will. I will tell you right if you tell me it's because they have great prices you are wasitinig my time. Please look at my initial post to udersand my requiremetns.Thank you

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 10:39:18 pm
content: Quote from: abraxa on January 28, 2018, 09:20:50 pmThank you - You are providing the type of assistance I'm looking for.

author: rsjsouza
author_rank: Super Contributor
timestamp: January 28, 2018, 10:52:12 pm
content: Quote from: DougSpindler on January 28, 2018, 06:35:58 pmI understand the issues from the news but, since I did not go to school here in the US, to me an oscilloscope (or whatever other technical/trade equipment) is unheard of in a high school class - thus my impression you were part of a more advanced or better funded school district.Quote from: DougSpindler on January 28, 2018, 10:39:18 pmIf your usage was focused in analog signals where the demand for more bandwidth or a better FFT is more important than multiple channels or decode, the Siglent or a Instek would be a better choice.

author: tautech
author_rank: Super Contributor
timestamp: January 28, 2018, 11:05:00 pm
content: Quote from: DougSpindler on January 28, 2018, 10:19:38 pmAll plainly understood.One thing I will address is Dave's comments on the Siglent PSU caps.I've sold Siglents for a good few years and many are well out of warranty now, all with zero PSU issues, zip, nada, none.He brings out that old chestnut every time he does a Siglent teardownand it's only his opinion as if you take the time to search online IF there was any problem you'd find it. In just a few minutes I can't and I've never heard of any. There's a good few members here with Siglent equipment so cap problems if any would be well discussed.QuoteIt's not quite that simple. You get what you think you'd be happy with and for your limited needs the cheaper option could suit your requirements. Like any modern equipment 'they' evolve and all the videos online can be quickly outdated with just one firmware release. As for channel count, I've sold gear to guys that were doing decode thehardway and with just 1 channel.Do your homework, ask colleagues and EE's that you might know.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 11:32:22 pm
content: Quote from: rsjsouza on January 28, 2018, 10:52:12 pmAppears you didn't see my original post. Or the post where I explained what I would be teaching. I am a college professor. I teach computer networking, virtualization and cyber-security classes. Our college is trying an outreach program with the high school where high school students are receiving college credit for taking the class. These kids are smart and eager to learn. I even have an 8th grader who really into computers/electronics.My budget for the class is $750. I plan on using Arduinos, so that's about $300. We need tools, $50. This leaves around $400 for a scope. Is it a luxury? You bet it is. But then again I don't know of any tool that's any better for teaching computer protocols, networking, cyber security and a little bit of programming.Do I know what I'm doing..... Sort of. Never taguth high school studnets. But boy are they sharp. My gols is to teaching them thrroughy hacking.I've looked at logic analyers and understand what they do. But for what I am teaching this way too close low level (voltages) for what I'm teaching. I need to be at Wireshar level OSI layer 2 and above if you will. A scope is a sretch for what I'm teaching but I think it's worth it. I wasnt these kids to know how to use a VOM/DMM to test for continuity and understand voltage and AC/DC current. But agin this class's focus is on computers, programming, networkign and cyber security.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 28, 2018, 11:43:26 pm
content: Quote from: tautech on January 28, 2018, 11:05:00 pmHere's the thing with the caps. We know that brand of caps had probelms with comptuer power supplioes. Can remember how many PS we head to replace or the cost involged to repalce thema adn the down time of the workers. They might be good now, or maybe in another 6 months when the scope is out of warranty they will start blowing. Every company makes a bad product everyone ins a while. If I recall correclty I lost 3 power supples in my personal computers. Not knowing they had bad caps spent hundreds of dollars to buy new PS. Think after spendins hundereds of dollars and wasted itme (like Dave) I'm ready to atrust thos caps?Or here's a better question. If you were building a rover to send to Mars would you use caps thet had massive QA problems in the past? Or fo with a manufacture that's had no QA issues. Yes time will tell. But I woudl rather you do the test with your money and not mine.

author: rsjsouza
author_rank: Super Contributor
timestamp: January 29, 2018, 02:50:28 am
content: Quote from: DougSpindler on January 28, 2018, 11:32:22 pmI did see your area of interest for this oscilloscope. My post was simply a highlight of the main differences of value proposition between Siglent and Rigol.From your original post it wasn't clear to me where you worked - my impression was that you were a high school teacher. My apologies.

author: imidis
author_rank: Frequent Contributor
timestamp: January 29, 2018, 03:17:39 am
content: I think a scope be it keysight, rigol, siglent even an old analog scope can be a valuable teaching/learning device.If money weren't an issue picking one sure would be easier!

author: DougSpindler
author_rank: Super Contributor
timestamp: January 29, 2018, 03:56:11 am
content: Quote from: rsjsouza on January 29, 2018, 02:50:28 amMaybe I was not clear in my original post. I'm not qualified to teach high school students, even through I'm a professor teaching at the college where some of these students might attend after high school. I'm a networking, firewall, cyber security instructor. When I was in high school we had an electronics teacher and classes. My teacher was fanatic. I was probably in the last class he taught vacuum tubes too. All of my digital electronics is self taught. But let me say my electronics teacher taught me well. In computer networking I use a VOM/DMM regularly. My high school had scopes. Those famous Heathkit scopes. Every student had a VOM and a scope. So I know who to use a scope in analog mode.... This whole digital think is new, but I think I'm getting it because I understand computer networking/Ethernet. In discussing which scope to buy I'm realizing all of my knowledge about Wireshark and Ethernet apply. Malformed packets just another way of saying the trigger voltage was not reached. (Greatly simplified, but good enough.)I'm hoping I can show students networking issues with the scope such as mutual-inductance/cross-talk and RFI.With the Arduino my goal is to show students the bits on the scope and have them decode frames on the SPI bus. I'm hoping I can show "hacking" by connecting a "foreign" Arduino on the SPI bus and injecting bit to mess things up a bit for them.IO hope to master just enough scope knowledge so I these students can see how easy it is for cyber criminals to hack into computers to commit computer crimes.

author: DougSpindler
author_rank: Super Contributor
timestamp: January 29, 2018, 03:58:48 am
content: Quote from: imidis on January 29, 2018, 03:17:39 amYou got that right. We spend so much money on our military and so little on our students. Maybe one day that will change. Don't wsa have less wars when people are more educated?

author: Fungus
author_rank: Super Contributor
timestamp: January 29, 2018, 10:18:56 am
content: Quote from: abraxa on January 28, 2018, 09:20:50 pmCorrect. The cheapest Siglent is $500 and only has 2 channels.Quote from: DougSpindler on January 28, 2018, 10:19:38 pmThat never deters our resident Siglent distributors from jumping in.

author: Unknown
author_rank: Unknown
timestamp: January 29, 2018, 03:06:15 pm
content: Actually, the Siglent SDS1202X-E (2-channel) sells for $379 but I am guessing that most of our distributors would provide you with an educational discount.

author: rstofer
author_rank: Super Contributor
timestamp: January 29, 2018, 03:18:52 pm
content: Don't overlook the possibility of tying in a little robotics. It is always illuminating to create a servo pulse and vary the width while watching the servo reposition. The scope trace adds a lot to the demonstration.PWM for motor speed control is another interesting demonstration.Maybe a PING))) device (ultrasonic transducer) where you can see the pulse going out and the ping coming back.https://www.parallax.com/product/28015A simple 4 bit counter shows up well on a 4 channel scope.

author: CharlieEcho
author_rank: Regular Contributor
timestamp: January 29, 2018, 03:35:18 pm
content: I think the Rigol is a good choice for classroom use, even if Siglent is the best hobbyist buy currently. The interface and front panel are closer to Keysight/Tekwith more dedicated HW controls (Siglent is more contextual/modal in terms of the panel and the menus, like LeCroy). I think that's good for education, plus if your students choose to get into electronics that's the more typical setup. Just put a camera on the screen and front panel and mirror it on a PJ or TV.You and your students might also enjoy messing with PyDSA, for doing signal analysis on an attached PC.https://github.com/rheslip/PyDSAI'm hoping I can show students networking issues with the scope such as mutual-inductance/cross-talk and RFI.I'm a scope noob myself, but is a 100MHz scope going to be able to show much in terms of ethernet crosstalk on UTP? I know CAT5E theoretically tops out at 100MHz but I thought you needed fancier scopes and spectrum analyzers or else special networking specific test gear for that. Maybe because of the way scope BW is rated (response falls off before the nominal upper limit) and the need for full BW and a wider view across multiple channels when testing ethernet cables? Or maybe I'm totally wrong.Either way, watch lots of W2AEW's vids before you start blasting your scope with RF.

author: Fungus
author_rank: Super Contributor
timestamp: January 29, 2018, 07:27:14 pm
content: Quote from: Siglent America on January 29, 2018, 03:06:15 pmMy bad for being unclear. I thought we were discussing 4-channel 'scopes.

author: nctnico
author_rank: Super Contributor
timestamp: January 29, 2018, 08:05:33 pm
content: Quote from: Fungus on January 29, 2018, 07:27:14 pmIf you factor in the educational discount the Keysight DSOX1000 (2 analog + 1 digital channels) should also fit inside a $400 budget but I'm not sure whether that includes protocol decoding and the waveform generator options (I guess not).

author: DougSpindler
author_rank: Super Contributor
timestamp: January 29, 2018, 11:33:29 pm
content: Quote from: CharlieEcho on January 29, 2018, 03:35:18 pmNot sure if I can do it, but going to try. To demonstrate crosstalk I don't beed Gig or 100 Meg, 10 is still supported os I thought i would try that.

author: CharlieEcho
author_rank: Regular Contributor
timestamp: January 30, 2018, 01:36:10 am
content: Makes sense. Should be plenty of BW for that.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 03, 2018, 02:17:32 pm
content: All Just wanted to let you know I did purchase the Rigol scope. It arrived today. Can’t wait to give it a try..... What the first thing I want to take a look at...... Gues it would have to be the sine wave from the mains. Can’t wait.And yes I watch Dave’s and and few other videos on how to blow the channel measuring mains.

author: Fungus
author_rank: Super Contributor
timestamp: February 03, 2018, 03:13:42 pm
content: Quote from: DougSpindler on February 03, 2018, 02:17:32 pmUmmm.... danger of magic smoke escaping!On the right of the 'scope there's a little metal loop which has a test signal. Me? I'd start with that.After that I'd connect a wire to the sound output of the PC and generate tones with Audacity, play some music, etc.Look at Arduino pins if you have one, do PWM with a potentiometer.The absolute last thing I'd ever do with an oscilloscope is connect it to the mains.Mains electricityisn'ta test signal. Not for multimeters, definitely not for oscilloscopes (which are grounded).

author: DougSpindler
author_rank: Super Contributor
timestamp: February 03, 2018, 04:51:11 pm
content: Quote from: Fungus on February 03, 2018, 03:13:42 pmI frequently use a DMM or VOM meter to measure or test for AC voltage on the mains and branch circuits. The DMMs I have are all rated to 600 V. So what’s th problem in using the mainstream test the. DMM or VOM?As for why using the mains for testing the scope, simiple answer is because it can be safely done. In fact, soon of the testing I would like to do includes having a scope attached to the mains to see the data being sent devices such as X-10 or PowerLine/Ethernet over AC mains.There’s only a danger of smoke if you don’t think through what you are doing.

author: abraxa
author_rank: Frequent Contributor
timestamp: February 03, 2018, 05:29:00 pm
content: Quote from: DougSpindler on January 28, 2018, 08:29:54 pmTo paraphrase you: "It would be irresponsible of me to [waste money]."Quote from: DougSpindler on February 03, 2018, 04:51:11 pmYou're right, it can be done safely. However, even professionals blow up stuff by accident. Or die.We're not trying to be mean here or spoil your fun, we're just trying to protect you and your equipment.Your previous posts have emphasized over and over that you're a software kind of guy. That, and the nature of your questions give off the vibe that you're at beginner level when it comes to matters of EE. That's perfectly fine and there's nothing wrong with that, it just means that dangerous situations should be avoided until you have a firm grasp of what the risks are and how to mitigate them. Given the questions you've asked here and your software background, I (and I assume others, too) are uncertain whether you possess the experience to do this, which is why we keep pushing the issue.Quote from: DougSpindler on February 03, 2018, 04:51:11 pmAs a teacher, you're aware that your students will be very eager to continue research at home if a topic really interests them. Even if you know how to handle mains voltage, would you trust a high school student to know this, too? If they see your setup at school and think "oh, this is easy" and do it at home as well and set the house on fire or die, how would you feel?It's one thing to probe mains at your own home for the sake of curiosity. It's another if you do it as part of a class and inspire students to do the same.

author: CharlieEcho
author_rank: Regular Contributor
timestamp: February 03, 2018, 06:20:47 pm
content: I know I shouldn't be encouraging this, but maybe a doorbell transformer would be an acceptable expedient? Outputs 16VAC. Attach a cord a use a portable GFCI.I agree it's a bad idea to demonstrate the physical act of probing mains service to impressionable kids.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 03, 2018, 06:35:08 pm
content: Quote from: abraxa on February 03, 2018, 05:29:00 pmThank you for looking out for me and my students. I learned how to use a scope in high school as vacuum tubes were being replaced by IC. The one think in Dave’s video about scopes being attached to the mains (which I don’t think he emphasized enenoug) was the clip and outer ring of the BNC is at Earth ground potential. So anywhere the clip is attached brining that Earth ground potential to the part of the circuit the clip is attached to. Or at least this is how I was taught to look at it.As for how dangerous 120vAC electricity is in the classroom I was trying to find how many deaths there are from non-court ordered electrocutions. The category is mixed one and includes exposure and radiation so I can get a clear number.Hear me out for a moment. I am not saying electricity doesn’t kill. In our country tht’s one way we carry our cour ordered death sentences. (And most of the time it is effective, but not always on the first spark). And let’s not include industrial accidents or people drying their hair with a hair dryer while talking a bath or a shower.So how dangerous is 120 vac in an electronics classroom? I’m going to ask if it could be a good teaching tool? Have you ever heard of a studnet in an electronics class getting killed? I know about every year in the US we hear of a high school althelte dying from a high school sports injury. I have never heard of a high school students being killed from electricity.When I was in high school I can remembered getting zapped a couple of time creating a arc with a screwdriver/test probe. Did it kill me? (Not yet). Did it ruin some equipment. Sort of. The diagonal cutter I was using once now became excellent wire strippers. (+1). And remember this was all before GFCIs.Guess what I trying to say coming in to close contact with mains can be an excellent learning experience for studnets. But will it kill them? Cause a spinal injury or broken bones. I think the worst thin that could happen is the might get a slight burn.I’m trying to teach these kids. And getting a zap of electric, static or mains is all a part of their learning experience. Can you give me a good reason whey they should get accidentally zapped every once in a while? You know there’s an arcade not too far from where I have where kids pay to get zapped. And yet they could come to my class and get it for free?Look I’m not saying I don’t implement any safety measures, I do. When students are working with mains I have make sure they are using a GFCI. And I teach them to test the GFCI before the excercise we are doing. So should a studnet attach alligator clips to another studnets chair the GFCI would trip before the kid would be smoking.You know the other stupid thing we did in high shool was charge a capacitor to 150 volts a either leave it on a counter for someone to pick up or toss it to someone to catch. As a high school kid that was a lot of fun todo, but as an adult I have to say boy was sure stupid of us. But you know something.... We learned. We learn never to catch a capacitor toseed to you. But getting serious for a monent what I taught me was to treat ever capacitor and every circuit even if no power is applied as if it were energized until proven other wise. It taught me to short/bleed all capacitors before touching. And isn’t that the lesson we want studnets to know?And as a side note this is interesting. There are people who have a medical condition which allows them to touch mains without feeling any electricity. It’s rare, but not unheard of. So you know if one of these kids doesn’t get zapped when he should it would inform them that they have this rare medical condition.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 03, 2018, 06:58:15 pm
content: Quote from: CharlieEcho on February 03, 2018, 06:20:47 pmExcellent idea. I already use GFCIs. And you know I have a door bell transformer - That would be perfect. I was thinking of a vacuum tube filament transformer. Hard to find nowadays. But yes a door heell would be perfect. Teacches isolations and step down. I have one on my junk box. And if not I’ll take the one out of my atttack. We disconnected our door bell years ago.

author: phil from seattle
author_rank: Super Contributor
timestamp: February 03, 2018, 07:17:43 pm
content: Quote from: DougSpindler on February 03, 2018, 06:35:08 pmWhile I think understanding the dangers is a very good thing, I suggest that "zapping" them will be misconstrued by parents, administrators, police and prosecutors. No matter how you construct the experiment, they won't understand. Don't do it. Imagine the average parent hearing "the teacher shocked me with electricity today!!". No amount of explanation will overcome their initial reaction. The above mentioned groups freak out over lesser stuff. You are setting yourself up for a world of hurt.

author: Fungus
author_rank: Super Contributor
timestamp: February 03, 2018, 09:18:09 pm
content: Quote from: DougSpindler on February 03, 2018, 06:35:08 pmThat's true.But... are you going to garantee that every single plug/socket your students come into contact with has been correctly wired and that the colors of the wires will let them know which is the "safe" one?Quote from: DougSpindler on February 03, 2018, 06:35:08 pmNo, but I haven't heard of a teacher who encourages getting "zapped" either. Will you be so smug when one of them gets hurt?If you knew a quarter as much as you think you do, you'd also know that getting "zapped" should never happen because you always wear work gloves when you're messing with live mains.They shouldn't be going near mains AC if you're not teaching them to be electricians, let alone clipping oscilloscope probes onto bare wires. Want to see a sine wave? Get a signal generator, FFS. Or an audio lead. Sheesh.

author: Someone
author_rank: Super Contributor
timestamp: February 03, 2018, 10:21:57 pm
content: Quote from: DougSpindler on February 03, 2018, 04:51:11 pmThe manufacturer of that specific scope strongly advises against using it to make measurements of the mains:Quote from: RIGOL User's Guide DS1000Z Series Digital OscilloscopeIf its not designed to withstand possible transients/faults/events on the mains and tested to safely contain them then don't even think about using it for that in public setting. Mains has an enormous fault energy and while you're thinking of a slight electric shock here and there those of us with more experience are thinking about arcs and equipment exploding with globs of molten material flying out.If you want to measure mains, you just bought the wrong scope.

author: tautech
author_rank: Super Contributor
timestamp: February 03, 2018, 10:52:53 pm
content: Quote from: DougSpindler on February 03, 2018, 04:51:11 pmQuote from: DougSpindler on January 28, 2018, 11:32:22 pmWhen I saw this some days ago, I assumed intelligent.Now I'm not so sure.Your school ischargedwith the safe education andprotectionof students while they're in your care.Please take this responsibility with the greatest of importance ! ! !

author: nctnico
author_rank: Super Contributor
timestamp: February 03, 2018, 11:52:45 pm
content: Quote from: DougSpindler on February 03, 2018, 06:35:08 pmMaybe not inside a classroom. When I was a teenager one of my friends from school died because he electrocuted himself by tinkering with mains at home. You have to take into account how well people can estimate their own mortality before learning them how to do dangerous things.

author: Someone
author_rank: Super Contributor
timestamp: February 04, 2018, 12:36:32 am
content: Quote from: tautech on February 03, 2018, 10:52:53 pmNote that "professor" is used in very different contexts around the world, in the US (and now some of Australia) its simply a term for academic staff and not the prestigious title as it is used in the rest of the world:https://en.wikipedia.org/wiki/ProfessorThe usual disclaimer that expertise in a specific field or specialisation does not necessarily apply to any other (even adjacent field) applies strongly here.A quick google of "Doug Spindler" associates them with a Diablo Valley College:https://en.wikipedia.org/wiki/Diablo_Valley_CollegeBut then their name does not appear in the staff listings so its possibly either a part time appointment or they have moved on to another institution.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 04, 2018, 03:01:09 am
content: I guess I see the OP's point: when we are exposing kids to a new thing, it is important to show the two sides of the coin. Ideally this should be done in a controlled environment with all the appropriate warnings and no possibility of collateral damage, but that is impossible due to uncontrollable factors: liability, parents' reaction, equipment failure and that 0.01% chance that someone will have further health issues or death.We certainly came from a different world, where we really experienced jolts, saw pliers or screwdrivers give up the holy ghost and rules and "responsible party" interference was much less present - we survived even after these zaps and jolts, but what about the ones who didn't? Statistics are cold and distant until it happens with someone close to you and that is why the overreaction/control exists today (some excessive, but still).

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 03:39:30 am
content: You guys are brittle. Hope do you expect studnets to learn if they don’t experience life? Did I ever say I was intentionally zapping kids? NO! I leave that the the Physics instructor who has a Van de Graaff generator? Did I even say I would intentionally let any of these studnets get hurt? Nope. I leave that up to the PE coaches. Yes parents trust their children to our schools and expect them to be educated and not injured. I agree - But then why are we teaching PE? I don’t think a day goes by when there isn’t a studnet who is being injured and some of the injuries they receive are debilitating taking months to heal.No one has been able to tell me of one instance where a student in an electronic class was killed or even had a long debiilating injury. Worst thing that happens in electronic class is the kid receives a mild momentary shock. And in some classes like physics they make devices (step up transformer) to shock one another .Are you folks trying to tell me you have never been zapped? Did it kill you? Are you maimend for life. Or did you learn somehting after getting zapped? I suppose after getting zapped you decided not to pursue a career in electronics.You do realize even with digital 3 and 5 volt circuits students can still get zapped.Folks we need to get this studnets trained for the real world. I had an professor in college who would call the campus electrician to change the batteries in a flashlight. Why asked why he didn’t do it himself he said batteries are filled with electricity and electricity is dangerous. I don’t what to get hurt.This is what happens when to try to over protect our children from leaning.

author: CharlieEcho
author_rank: Regular Contributor
timestamp: February 04, 2018, 04:18:21 am
content: Are you folks trying to tell me you have never been zapped? Did it kill you? Are you maimend for life. Or did you learn somehting after getting zapped? I suppose after getting zapped you decided not to pursue a career in electronics.You do realize even with digital 3 and 5 volt circuits students can still get zapped."Zapped" is not a binary condition. That's why most of us are still here. Getting "zapped" with 5VDC is not like getting "zapped" with 120VAC -- I've experiened both and I'd rather not experience the latter ever again. I got lucky. And wouldn't you know it, it happened when I was a dumb 13 year old kid.It's entirely likely that everything would go fine. And from a probabilistic perspective, yeah, your students will likely not go stick a free Harbor Freight meter into the outlet at their next family gathering. But, improbable is not impossible. Your students didn't learn this stuff in the age of vacuum tubes. Indeed, they haven't learnt it at all, you're introducing it to them and it behooves you and your school to do so with a great deal of caution and an emphasis on safety.When's the last time your students paid perfect attention to any of your lessons and came away with a 100% understanding? Treat youth like youth. Beginners are beginners. Take risks on your own time.Also, if you don't think you're going to be in the shit career-wise if one of your students gets shocked messing with the mains -- in or out of the classroom, and regardless of whether it kills them -- then you've got your head somewhere south of the books. And north of the ground.

author: Someone
author_rank: Super Contributor
timestamp: February 04, 2018, 05:03:11 am
content: Quote from: DougSpindler on February 04, 2018, 03:39:30 amYou could also find it impossible to show that no student has ever died in an electronic/electrical classroom, record keeping is very inconsistent and hard to access so the deaths that have occurred are very hard to extract with such specificity. Then electronic/electrical classes are so rare that its hunting for a rare event in a tiny population and there may well have been no occurrences but that doesn't mean ignoring basic safety requirements is the right thing to do.Electrocutions have and do occur in schools in the US:http://www.thespectrum.com/story/news/local/2017/03/29/schs-student-severely-burns-himself-school-equipment/99787512/http://www.delcotimes.com/article/DC/20100925/NEWS/309259991https://www.cpsc.gov/s3fs-public/Electrocution-Report-2004-to-2013.pdf?V_9Zl10pv4Wz03uBPRx78IctKRABjYDvBut its teachers such as yourself lacking the most basic understandings of the material needed to teach it safely that is causing the ever increasing red tape and requirements upon which teachers need to attain before they can teach specialist topics (I know of people who're retired rather than going through the modern reassessments to be qualified to continue teaching what they've been doing safely for a lifetime). From what you've posed and the dismissive attitude to safety you're the worst of the worst, perhaps you'd like to confirm your current position and faculty?110V is still able to deliver very dangerous fault conditions:And you can't simply rely on breakers to solve all the problems:Safety requires multiple layers of protection, single point failures should not leave a student in danger so even a circuit with a RCD/AFCI/GFCI (or combination there of) is still not enough to ensure safety.Quote from: DougSpindler on February 04, 2018, 03:39:30 amThey should be learning in well planned courses with teachers/instructors who understand the material and can teach it safely. These experiences can be taught to students but not safely by you.Quote from: DougSpindler on February 04, 2018, 03:39:30 amNo, this is what happens when there are charlatans posing as concerned teachers.

author: Someone
author_rank: Super Contributor
timestamp: February 04, 2018, 05:15:21 am
content: Quote from: CharlieEcho on February 04, 2018, 04:18:21 amEven with explicit step by step instructions noted as essential for safety some students will ignore it anyway, and then complain if you try and eject them for being dangerous.... When there is safety involved it really requires one on one supervision.Quote from: CharlieEcho on February 04, 2018, 04:18:21 amI wouldn't let students anywhere near live mains, if they were doing some work with mains then it would be inspected before energizing and that would be inside an appropriate grounded/armoured/interlocked enclosure as appropriate. Teaching mains technology/coursework is often done with either low voltage analogs (24V AC etc) or completely insulated to the standards of consumer equipment so that there is no possibility of exposed shock hazards, as above voltages can be measured on appropriate step down transformers integrated into the benches or equipment, and currents by non contact methods all routinely hi-pot tested for breakdown/damage of the insulation. As much as some people dislike the shrouded banana plugs they sure made it easier to let students connect mains voltages.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 05:35:29 am
content: Quote from: Someone on February 04, 2018, 05:03:11 amFreind pelase read waht I wrote. Your post is proff of what I have been saying.Have you ever been shocked?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 05:45:27 am
content: Quote from: Someone on February 04, 2018, 05:15:21 amWhy are you so agaisnt studdnts learning? By placing them in such as "safe": envoronemtn they aren't really learning are they. Why not let them learn in an envoroment where they are supervised and shoudl something happen there are people who can assist. Much better than having them along on a job site where they might be alone.Friend you shoudl knoe 24 VAC can prduice voltates whcih can zap stedents. So what's being gained?I will aslk you again, have you ever been shocked or zapped?Please read my posts and respode to what I have written.

author: imidis
author_rank: Frequent Contributor
timestamp: February 04, 2018, 05:51:11 am
content: If I had a choice, I would rather get zapped by 120V AC than a spark plug wire from a car. Home electrical I have no qualms about replacing anything electrical in the house, though I would absolutely draw a line at modifying the electrical panel.When I was young, I mean really young I stuck my finger in a nightlight socket at of curiosity of how it worked. I didn't really learn anything other than it was a weird feeling.In my younger years I assisted in plumbing and heating, it was a pretty valuable experience as it ranged from low voltages to higher. eg gas thermostat vs electrical heat thermostat. (AC, Heater)In some situations I will work on live wires, in others I'm extremely cautious. Usually getting a marette on the live, whether active or not is first priority, just so if someone that doesn't know better doesn't have an incident, until the new (whetever it is) is installed.In more deadly situations its good to have two testers (usually use non contact detector) to verify the circuit is not live.Short circuit situations can be quite hazardous, breakers can vary in ratings. One thing I've always avoided is a short, also never giving voltage a path.The ac jolt doesn't bother me that much but I wouldn't really suggest anyone try it.There are some situations where it could be dangerous.Around 20 years ago someone brought in a shock pen (we had rather nefarious pen thiefs around) and thought, if just the wrong person experienced that and had a fit, they would probably have a supervisor breathing down their neck.I hated that job. We learned all this safety about, lockout, tagout, forklifts, had an operators license. However, once I got in that position it was one of those, well we can't follow those safety rules here. Warning signs about forklift traffic were ignored by the mechanics and engineers. Lucky none of them ever got killed. For those that don't know, forklifts literally have tons of counter weight. That wouldreallyruin your day getting hit by one.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 05:52:41 am
content: Quote from: rsjsouza on February 04, 2018, 03:01:09 amThank you. Any idea how many studnets have died for being zapped or an electrution in an electronics class? We all know studednts have died at school. But has there ever been one in an electrocins class? What's the worst injury that can happen in an electrocnics class? We can rule out death. Maybe a slight burn? Does being zapped cause perminent damge? Don't think so.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 06:10:43 am
content: Quote from: imidis on February 04, 2018, 05:51:11 amSounds like you've been zapped a few times. Did it kill you as others are saying could happen? And yes let's not forget about spark plugs. If I recall correctly the voltage is either in the 20k old school or 40k volt range.Of course my students don't open up and play with the mains int he breaker pannel. But at each student station they have a mains to plug things into.I think we've all been zapped in our life time. Sticking a pin an electrial outlet i think is something most of uss do when we are 3 or 4 years odd. We are curious and want to know how things work. We experiment and explore.One of the other posters suggested using 24 volt. Yes we could, but then what are we teaching our students. Getting zapped with 24 volts is just not the same as 120vac. Then in the workplace were an employeeds gets zapped with 120vac they are going say what happnd? I never learned that in school.I try to be the best teaching I can to these students. I let them fail... Why? So they learn. I would say 95% bof my fellow instructors wnat studnets to follow a strict set of instruction in the lab and don't let them deviate or try something on their onw. Is that learning? Or parrioting? Studnets who finsih my class can think and have critial thinking skills?What klind of emplouyee wound you want? One who can think and solve probelms? Or one who just follows a written set of instructions.

author: imidis
author_rank: Frequent Contributor
timestamp: February 04, 2018, 06:47:57 am
content: Quote from: DougSpindler on February 04, 2018, 06:10:43 amObviously I'm still here.But it is important to teach precautions and basics. I'm not really sure what the voltage was on those wires, but it felt unpleasant. I've worked on a lot of cars and I only let that happen once. It was that unpleasant.Problem solvers good, but I'll never be an employer though.I agree failure is the best way to learn. Just hopefully while avoiding costly mistakes. I push the boundaries of what I know, but nothing makes your heart sink more when you think maybe you've damaged a $16k piece of equipment. (this equipment was no touchy voltage unless fully drained otherwise deadly) I would not want to find out what that feels like. Otherwise I wouldn't be here.Luckily I had the service manual, those are instructions I would not ignore. Got to know where to draw the line though.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 06:52:57 am
content: Quote from: imidis on February 04, 2018, 06:47:57 amGlad you are still with us. I agrree with you it all comes down to education.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 04, 2018, 08:44:20 am
content: Apparently not many have copped a nice 'can't let go...' 240 voltZAPnor had hot copper or brass shrapnel fly at their eyes from an active to neutral shortor taken out an oscilloscope, fried it's croc ground clip and blow the mains breaker (if it tripped with correct rating)Perhaps 120 volts is a safer voltage to work with, and less chance of DIY adventurous home student barbeque ?

author: CharlieEcho
author_rank: Regular Contributor
timestamp: February 04, 2018, 03:41:03 pm
content: Sure, 120VAC is marginally safer than 240, but 120 is enough to do serious damage. And when I was shocked as a kid by clumsily bridging the terminals while rooting around in a floodlight-timer box, it was enough to convulse the fingers I had extended into it. I remember having to pull my hand away by rotating my shoulders. Bad and scary.As has been said multiple times, the question isn't whether this is safe to do for OP, but rather wise to demonstrate to totally uninitiated students.If the point is to demonstrate the properties of AC then stepping down the voltage is the responsible thing to do, at minimum. (And even then, I don't like that it's coming from the utility service vs. a more tightly regulated lab AC source.)

author: rsjsouza
author_rank: Super Contributor
timestamp: February 04, 2018, 06:08:35 pm
content: Quote from: DougSpindler on February 04, 2018, 05:52:41 amJust like you, I don't know about these statistics. Slight burns and shocks are consequences of the learning experience, and several reports and some interesting movies about electricity safety (which could be shown in a class) can be seen in the thread below.https://www.eevblog.com/forum/chat/electric-shock-experiences-for-those-still-alive/Long term consequences of electrical shocks were subject of study of a professor in Brazil that was able to find some correlation with kidney and cardiac abnormalities months after the shock - unfortunately I couldn't find the reference (this was long before the internet).Regardless, several safe experiments that showcase electrical stimulus (stopping short of an actual shock) are not unheard of. Also, the Harbor Freight freebie meters can also be turned into another controlled experiment that showcases the power of electricity and misuse of test equipment. The charged capacitors become an experiment that shows the dangers lingering inside modern equipment and their switching power supplies. Heck, you could even show some of ElectroBoom's videos for ideas.One thing you can't control (nobody really can) is if a more enthusiastic student decides to reproduce these at home without the same level of safety - but that would be very circumstantial.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 07:09:11 pm
content: Quote from: rsjsouza on February 04, 2018, 06:08:35 pmI've been thinking about this a bit more. Our high schools and colleges teach welding. While in electronics we try not to heat metal to it's melting point in welding they do. I suspect there are far more burns and injuries in welding than electronics.At all of the local elementary schools they have a gardening program. What could be safer, than a class of kids gardening right? One little girl was stung four times by bees. What's worse, being zapped by 120 vac or 4 bee stings?Our schools are dangerous places, but then so is the world. Our schools are preparing students for life in the "dangerous" world. The way students learn is by making mistakes. And I can tell you no matter how much safety training students receive they think they are smarter and something bad is not going to happen to them when they do something stupid.Having a piece of hot welding slag causing a burn, bee stings in the garden, or getting zapped is all part of the learning process.If you were hiring a new employee wouldn't you want someone who had been jolted a few times? Means they made some mistakes and hopefully learned something. Our would you want someone who completed each lab exercise step by step which resulted in the perfect outcome? (Kind of like making a TV dinner.) I guess what I'm asking is if I were teaching students to be cooks. I could teach them to follow instructions which would make them perfect cooks for the fast food business. But wouldn't your rather want to hire a cook has experimented a bit?Look I'm just the professor truing to give this "kids" the best educational experience I can.Bee stings

author: Fungus
author_rank: Super Contributor
timestamp: February 04, 2018, 07:39:49 pm
content: Quote from: DougSpindler on February 04, 2018, 06:10:43 amThread over.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 04, 2018, 10:13:29 pm
content: Quote from: Fungus on February 04, 2018, 07:39:49 pmIn the US, they might learn better if zapped with 12 volts AC, and advised the 120v mains will be be 10 times more 'shocking' and or lethalIt's safer (cough...) and the x10 math is easier to remember tooIn 240 volt Australia, 24 volts AC is still sort of ok to play with and easy on the math too,but just remember when playing with it"If you drink and DIY, you're a bloody idiot..."

author: rstofer
author_rank: Super Contributor
timestamp: February 04, 2018, 10:17:39 pm
content: I would think that having students working on voltages over 50V would be considered reckless endangerment.It's one thing for my father to teach me, that's family. But students are somebody else's family and in our litigious society having them work on mains voltages exposes everybody in the food chain, including the local taxpayers, to enormous financial risk.And for what? Just because we can? There is absolutely nothing to gain by this.At the high school level (and below), I would probably limit things to 4-AA batteries or less and definitely no LiPo batteries. Maybe all the way up to 9V wall warts but that's the limit. College level I would probably go all the way to 50V DC.College level Industrial Technician classes are the exception of course. There we can get serious about electrical systems.There are plenty of things to learn that don't involve jamming probes into wall outlets.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 04, 2018, 10:29:15 pm
content: Personally, if it was my class of shifty, impish, risk taking, pretend nerd, prank pulling 'good keen students'litigious little Fersit would be a a LOT safer to sit them down and watch an afternoon of 'ElectroBOOM' Youtubes,and once the giggling subsidessome Fluke flashover and related youtube videosbefore hitting the lab benches

author: Fungus
author_rank: Super Contributor
timestamp: February 04, 2018, 10:31:19 pm
content: Quote from: rstofer on February 04, 2018, 10:17:39 pmThis.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 04, 2018, 11:26:09 pm
content: The responses are interesting. You know I do have the option of teaching students with virtual equipment. Using virtual lab equipment, DMMs, scopes, signal generators there would be no possible way for the students to get inured or zapped. The student use virtual probes and attach them to virtual chips all while remaining completely safe. I've talked to employers who have interviewed students who have graduated from programs where they used virtual equipment. They tell me they won't hire these graduates because they don't even know how to turn the dial on a physical multi-meter or which way to turn a screw driver to loosen a screw.Are those the kind of skills you would like your fellow workers to have?

author: ghpicard
author_rank: Contributor
timestamp: February 04, 2018, 11:40:00 pm
content: Quote from: DougSpindler on February 04, 2018, 11:26:09 pmI'm absolutely sure that having being exposed to unsafe operating conditions (and training) won't get the job for them either. A person whose safety understanding is lacking is more a liability than an asset to any company.

author: daybyter
author_rank: Frequent Contributor
timestamp: February 04, 2018, 11:53:54 pm
content: https://www.google.de/url?sa=t&source=web&rct=j&url=http://www.educator-resources.com/pdf/Teacher%2520Tort%2520Liability.pdf&ved=2ahUKEwjl68eNuY3ZAhVRJewKHQvABooQFjAAegQIERAB&usg=AOvVaw2mJgi39wy1AwntLLTlEXkDYou might make it on national TV? I wonder if rigol is happy if their product is featured in such a case?But since there is always a slim chance, that one of the kids has a heart problem, so your zapping idea might be this kids terminal experience.Instead I would go to your boss and ask if (s)he is ok, if you hit the kids with a whip. That seems less dangerous to me.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 05, 2018, 01:38:17 am
content: Quote from: ghpicard on February 04, 2018, 11:40:00 pmWhat is unsafe? Why do you think these students aren't receiving proper safety training? Or being exposed to unsafe conditions?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 05, 2018, 01:51:57 am
content: Quote from: daybyter on February 04, 2018, 11:53:54 pmNot sure why you are bringing religion into this. The document you referenced is about church schools. I am a professor at a public institution.But since you brought religion into this...... A pastor was un the pulput and admitted having forced a minor to have sexul relations with him. (It was one of his bible study studnets.) What did the congeration do? Stood up and applauded for his honesty. Wait a minute he ruined the life of a young women and committed a felony. I have to ask why was he not arrested? And you are worred about a student getting zapped and suing the school.Again I will ask in your career working with electrity have you ever been zapped? Did that runin you for life?

author: rstofer
author_rank: Super Contributor
timestamp: February 05, 2018, 02:34:57 am
content: Quote from: DougSpindler on February 05, 2018, 01:51:57 amThat isn't the point!Johnny: "Hey dad, I got an electric shock in school today!"Dad: "That's great! We just won the California lottery! Maybe you should lie down and practice moaning while I call a lawyer. Roll your eyes and twitch a bit!"

author: EEVblog
author_rank: Unknown
timestamp: February 05, 2018, 03:54:51 am
content: If this thread doesn't stay on topic then I'll lock it and/or delete all the off-topic stuff.Come on, a thread on which scope get ends up at religion is going too far.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 05, 2018, 04:59:19 am
content: I purchased the Rigol scope (received it on Friday) and very pleased so far. Screen is larger than what I expected. Screen and text on the screen is very readable. If one reads this post you will see I did consider other brands of scopes and you will see my reasoning for not purchasing those other brand. For $350 (USD) I think I got an excellent value.Bottom line, if you are in the market for a new scope on a limited budget BUY the Rigol. The other piece of test equipment I purchased was a two channel logging DMM. This thing is an incredible value at $105 (USD) Mooshimeter with Bluetooth. This device uses your smartphone or iPad for the display which has it's advantages. I have 3 Fluke meters, and a couple cheap ones but they don't have a data logging. This one does and like the Rigol scope I would give both of these products 5 stars. They are easy to use, well built and will be used in my lab and classrooms for years to come.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2018, 09:03:12 am
content: Note the CAT rating printed on the front:I assume you'll be teaching CAT ratings in your electronics class, given that you're messing around with bare AC mains wires, etc. as part of the curriculum.

author: aabbcc
author_rank: Regular Contributor
timestamp: February 05, 2018, 09:14:45 am
content: Quick question about the Rigol DS-1054Z since I don't know anything about oscilloscopesBatterfly a good deal for the below items for 440 eur, and since I'm in the market to upgrade all of my equipment this sounds good!Rigol DS1054ZExtech EX330HAKKO FX-888DIs the DS1054Z able to act as a frequency counter? I need to tune a few synths VCO's I built and thus need to measure 400-500hz.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2018, 09:17:05 am
content: Quote from: aabbcc on February 05, 2018, 09:14:45 amYes.Quote from: aabbcc on February 05, 2018, 09:14:45 amNo problem.

author: nctnico
author_rank: Super Contributor
timestamp: February 05, 2018, 09:54:37 am
content: Quote from: Fungus on February 05, 2018, 09:17:05 amA real frequency counter has a much higher resolution than an oscilloscope so depending on the requirements the answer may also be 'no'.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 05, 2018, 10:14:46 am
content: Quote from: Fungus on February 05, 2018, 09:03:12 amSo with 10x probes it's duh... 10 Megohm /130pf 3000 volt RMS CAT 10 ?No IPxx rating on the Rigol ?Pool party trippy waveform DSO demos accompanied by trance moozik on schoolie nights are out then...BS aside, not a good idea to go straight up mains probing with stupdents around,especially if no one's wearing safety eyewearEyewear and gloves is a MUST for any mains work, end of storyTyped here by a VERY LUCKY mis-informed overconfident survivor

author: rf-loop
author_rank: Super Contributor
timestamp: February 05, 2018, 10:24:10 am
content: Quote from: Fungus on February 05, 2018, 09:17:05 amYou did not even ask how accurate it need be and what is needed resolution/accuracy for this tuning anmd then you professionally answer: No Problem.Perhaps no problem but this you or onyone else do not know because original question do not include enough definitions.So lets first ask more questions before start giving answers.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2018, 11:39:40 am
content: Quote from: Electro Detective on February 05, 2018, 10:14:46 amDo you know students? There's alwaysone.( Actually that's maybe the best possible outcome here. The shiny new Rigol gets zapped instead of a student. Lesson learned?)Quote from: Electro Detective on February 05, 2018, 10:14:46 amEar protection is good, too. Electricity can go bang.

author: aabbcc
author_rank: Regular Contributor
timestamp: February 05, 2018, 01:30:50 pm
content: Quote from: Fungus on February 05, 2018, 09:17:05 amQuote from: nctnico on February 05, 2018, 09:54:37 amQuote from: rf-loop on February 05, 2018, 10:24:10 amThanks for the replies!I guess my questions maybe doesnt contain all relevant information since I'm really new to all of this but a resolution of 3 decimal points should be good enough.I need to be able to octave trackck the VCO.For exampleC0 Note1v Octave V: 0.0833Expo Output: 0.1655Frequency: 65.4078A2 Note1v Octave V: 2.8333Expo Output: 1.1136Frequency: 440.0092Tuning instructions for another synth:The 1V/Oct on each board should be trimmed to 1V/oct. Input a 0-4V signal in the tune input (A nice to have if the rigol can do this, otherwise I can do it from a different synth). Check point 1 with a frequency counter. Adjust so that you have a frequency doubling from 0-1V, from 2-3V, and 3-4V.The trimmer on both board two and three is for the VCO tune. Hook a frequency counter to point 1 and adjust the tune slider for 440Hz. Then measure point 2 and adjust the trimmer for exactly 450Hz. Repeat on next board.

author: ghpicard
author_rank: Contributor
timestamp: February 05, 2018, 01:41:34 pm
content: Quote from: aabbcc on February 05, 2018, 01:30:50 pmFor this precision you need a proper frequency/period counter.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2018, 02:17:29 pm
content: Quote from: aabbcc on February 05, 2018, 01:30:50 pmAt 500Hz a DS1054Zwillshow 3 decimals on screen using its hardware frequency counter. It's usually quite accurate but I don't have anything else here that can measure to 3 decimals to compare the two side by side. I'd probably trust it to two decimals.If you have a known-good reference frequency and a 2-channel 'scope then you can connect both signals to the 'scope and turn the trimmers until the signals don't drift relative to each other. This will be at least as accurate as looking at the frequencies to three decimals, maybe more.Quote from: aabbcc on February 05, 2018, 01:30:50 pm...and now we're at 4 digits.Quote from: ghpicard on February 05, 2018, 01:41:34 pmYes, a dedicated device is always better.

author: ghpicard
author_rank: Contributor
timestamp: February 05, 2018, 02:50:22 pm
content: Quote from: Fungus on February 05, 2018, 02:17:29 pmThe specification states, for the delta time measuring accuracy: Single-shot: ± (1 sample interval + 50ppm × reading + 0.6 ns)In this case the most relevant term is the (50ppm x reading), which leaves the 4 digits counting from the 1st. one. The measurement would be accurate to the 1st. decimal digit. I think aabbcc is asking for 7 full digits precision, something he will not get in a direct way from an oscilloscope. Of course, as you said previously, there are indirect ways to use an oscilloscope to provide that precision, but to do that one needs a signal source precise enough too

author: nctnico
author_rank: Super Contributor
timestamp: February 05, 2018, 03:59:05 pm
content: Quote from: ghpicard on February 05, 2018, 02:50:22 pmIf he needs to adjust trimmers then I strongly doubt he will get 2 digits of precission long term and/or with temperature variations.

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2018, 04:12:45 pm
content: Quote from: nctnico on February 05, 2018, 03:59:05 pmCalm down, "trimming" can be digital, too.I didn't know how his devices work, "trimmer" seems an appropriate word.

author: ghpicard
author_rank: Contributor
timestamp: February 05, 2018, 04:17:54 pm
content: Quote from: Fungus on February 05, 2018, 04:12:45 pmIt seems that his application is music so "tuning" could be a better word.Anyway, I think we are straying from the original topic (at least, the requirements are totally different) and this one could be worth a thread of its own...

author: Fungus
author_rank: Super Contributor
timestamp: February 05, 2018, 04:41:40 pm
content: Quote from: ghpicard on February 05, 2018, 04:17:54 pmAnalog synths are well known for being tempremental and a bit out of tune. All those VCOs, etc.(Although to be fair a lot of the error comes from tolerances of the resistors in the analog keyboards)

author: imidis
author_rank: Frequent Contributor
timestamp: February 05, 2018, 04:44:06 pm
content: One of life's lessons sadly even from reputable, or what you think are reputable companies. Perhaps are not, and may be lying to you. Do you have confidence in your equipments CAT ratings?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 05, 2018, 09:34:38 pm
content: Quote from: imidis on February 05, 2018, 04:44:06 pmGreat question...... In the computer industry which is what teach students do you have confidence in anything? Heck there are fake Cisco routers and router boards and even Apple has to contend with fake Apple Stores.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 05, 2018, 09:46:30 pm
content: I think it's interesting that a number of you are bullying me and telling me I'm incompetent for not protecting students for accidently getting zapped in my class. Now we are getting into gloves, eye and ear protection.It's ocuring to me we might have different defiantuons for the word mains? So before you zap me with a cattle prod what's your defination for mains? Mine is household voltage. I'm in the US so that would be 120 vac. When studnets measure the votage at the "mains" at a power supply of say a router to see if the fuse is good. We are takling 120 vac. For this test are you telling me they should be weaing gloves and have eye and ear protection?Is this something you even do?How many of you working in the electronics filed have never received a zap? Come on, be honest.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 05, 2018, 11:06:32 pm
content: You want honest? LOL, buckle up mateLots of zaps here, a great survivors collection actually,and a firm reinforced belief in God and or Crew above (Thanks again!)Let's see:nice wacks, cracks, sparks, and shrapnel at 6, 12, 24, 48, 60v DC, from automobile, UPS, server and laptop PSUs2 awesome near death experiences on 240 volts AC, one as an unnattended child playing with a junked 1960s open backed stereo 'all in one',and one much later when I got into repair workIf I was taught and cautioned properly back in the day, especially about earth ground bonding at the mains,none of the above would have happened, as they haven't since for years once I unlearned a lot of mashed electrical fundamentals and electronics voodoo BS,and relearned properly how stuff works, and what scenarios are possible when stuff isn't working as it's 'assumed' to be.FWIW back then (as today!) had I been wearing $4.99 tradie eyewear, $2 shop cowhide gloves and jammed some tissue in my ears, I would have needed less luck to get through the above unscathedMost stupdents in the classroom are more concentrated on their Farcebook status and hipster nonsense than any cautions the teach is trying to pump into them, let's get real here...Protect the little twats as best you can from themselves,otherwise their cashed up parents will zap the school and you real good,into legal labyrinths, financial oblivion,and a future applying for non-teaching dead end jobs!Please consider before applying the bullying stamp here

author: rstofer
author_rank: Super Contributor
timestamp: February 06, 2018, 12:02:34 am
content: Quote from: DougSpindler on February 05, 2018, 09:46:30 pmAs an employer (if I were one), I would be obliged to see that my employees had suitable personal protective equipment whenever they worked on anything over 50V. At a minimum, eye protection and low voltage rated gloves. Seriously! I would have to provide gloves for work on energized 120V circuits.This is the rubber glove but it can't be used without the protectors:https://www.magidglove.com/Salisbury-by-Honeywell-E0011-11--Class-00-Rubber-Linemens-Electical-Gloves-E0011BL10.aspxhttps://www.magidglove.com/Magid-PowerMaster-Linesman-Low-Voltage-Protector-Gloves-126049-1-12604115.aspxMoreover, I would have to have a rather complex sign-off procedure before energized work could be done at all. There would need to be a sign-off on WHY the work had to be done while energized. I would also have to have a documented Lock Out - Tag Out (LOTO) training program. We can't just turn off the breaker, we need to prevent someone from turning it back on and we need to tell the world why it was turned off. (if we couldn't effectively lock the breaker, it had to be unwired.For those of us who were considered 'jailable company employees', we took this stuff seriously. No screwing around; written procedures, documented training, spot inspections, the whole program.Everybody gets to make their own choices but some are really bad...

author: tautech
author_rank: Super Contributor
timestamp: February 06, 2018, 12:31:25 am
content: Quote from: DougSpindler on February 05, 2018, 09:46:30 pmReally, poor you.There is no way students at school at this level should be exposed to anything that 'zaps' them and at this age the teaching of formal safety procedures is not given, it's reserved for after they start employment and at a time when they could be viewed as more responsible.My early electronics 'education' started at seven when pop bought me a Philips 2 transistor electronics set that was powered with a 9V battery. Before teenage years I was fiddling with petrol motors whose ignition systems gave a healthy wack which is where 'respect' for electricity was gained. In my first year at high school I'd already been working on valve radios and got several shocks, the worst of which was 700V from a HV plate PSU. 230VAC mains 'tingles' followed in later years when I thought I had sufficient 'ability' and experience to start working with it.From that school of hard knocks (AND NO FORMAL TUITION) I've not had a shock in ~30 years due to the healthy respect gained....in my own time !Teach them about the dangers but DON"T expose them to any ! ! ! ! !I've seen educators like you before......I'm always right.Yeah right !

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2018, 08:25:14 am
content: Quote from: DougSpindler on February 05, 2018, 09:46:30 pmIf that's how you're teaching them to find out if a fuse is good then maybe a rethink is needed.

author: imidis
author_rank: Frequent Contributor
timestamp: February 06, 2018, 09:00:19 am
content: Ok going to be really serious here. Seriously rethink what you are doing and the knowledge you may have or not have.

author: Kean
author_rank: Unknown
timestamp: February 06, 2018, 10:05:56 am
content: I've got to agree with the majority here. The OPs assertion seems to be that the best way to teach is by letting people make mistakes. While that may be a good way to *learn*, it is never a good way to teach. Especially when someones heath or life is on the line.In any business or education environment, intentionally exposing someone to risk - even if well intentioned - is going to be good grounds for dismissal, maybe even getting sued. The limit for safe handling without special procedures is generally considered to be around 50V, and there are exceptions even to that. I'm am personally especially careful with anything above 30V, or where high currents are possible.If you want to measure mains voltage, use a multimeter & probes appropriate for the task (i.e. CAT II or better).If you want to check mains waveform, you can use a isolation transformer - preferably one with a lower secondary voltage, like the doorbel transformer discussed above. Or you could use an oscilloscope designed for power electronics use - typically battery powered for isolation, and with a high voltage probe.If you want to check a fuse, remove it and use a mutlimeter in ohms mode - and never do it with power on. In fact on some older equipment, it can be dangerous to remove a fuse while powered due to poor fuse holder design. I still occasionally see low voltage fuse holders used on new mains equipment.Yes, there are ways to do all of these in the non-ideal ways suggested above - and you may even do that in your home environment where you take that risk on yourself, but you don't go doing that in a workplace, or worse teaching others to do it. By doing so, you are placing both your job and others at risk. If you don't agree, please chat with your boss about risk management training.And yes, I've had some minor 240V shocks in my life - but only as a teenager when I really should have known better. And now I do!

author: Dubbie
author_rank: Unknown
timestamp: February 06, 2018, 10:10:07 am
content: This thread just seems absolutely ludicrously insane to me. I hope you think it’s worth it to face a lawsuit you will surely lose in order to teach students how to be reckless. (Your posts make it sound like you have no clue what you are doing)Real professional electricians don’t get shocks. Only lazy and hubristic ones do. The last time I got a shock was as a young teen poking around in a plugged in amplifier. I was completely unqualified, uneducated and unequipped to be doing something like that. Since then I made an effort to educate myself and cultivate a attitude of safety. I now regularly work with mains and have never had a shock or near miss since then.I know two people who were electrocuted (that means game over) both were uninterested in following safety rules. It’s not an abstract thing. It happens to real people.

author: Fungus
author_rank: Super Contributor
timestamp: February 06, 2018, 10:29:43 am
content: To use some analogies:Would you teach firearms use by letting them make mistakes?Would you teach somebody to drive by trial and error (a few near misses at intersections would teach them what those pesky red lights mean, right?)No, you wouldn't. You'd start by teaching them the correct way to do it (ie. gloves, safety goggles) then if anybody messes up or doesn't follow the rules you'd shout at them. If they want to ignore procedure and make mistakes in their own spare time then that's their problem butthere's no place for it in a classroom.Were you going to mention gloves and safety goggles at all? And ... if you're going to mention it then what will you say when somebody asks why they're not following the safety rules?"I secretly want a few of you to get zapped as a learning experience. You'll thank me for it later."Or ... maybe you weren't planning on mentioning any safety procedures at all. I'm sure that'll come across well in a job interview.

author: SMB784
author_rank: Frequent Contributor
timestamp: February 06, 2018, 05:00:13 pm
content: Take it from a fellow educator: if you tell your students to plug their oscilloscope probes into the wall, they are going to think that kind of behavior is ok, and let me be clear:it is not ok. Sure, maybe they will get shocked and learn not to do it, if they survive. However, they might also not get shocked, and those that don't will wind up thinking they know what they are doing, and will end up dying somewhere else doing something incredibly stupid that you have just taught them how to do.It is yourdutyas an educator to teach children how to be safe with electronics. Plugging your oscilloscope probes into a wall socket (or any source of high voltage, AC or DC) isnotsafe. It is completely idiotic, and it makes you a bad teacher.The most dangerous person in the work place is the one who thinks they know what they are doing. Don't let your students be that person.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 07, 2018, 05:38:18 am
content: Just about all of you have told me you've been zapped, and then you tell me I must be a horrible teacher if any of my students accidently get zapped. After getting zapped how many of you were immediately rushed to the hospital? Received a permanent injury? Required medial attention? Or did you just get zapped and think boy did I just do something stupid, and get on with your life?So after you get zapped you tell me this is something that should NEVER happen to any student. Keep them safe, do allow them to go anywhere near voltages for 30 to 50 volts or more. Students are a lot smarter than you think. They have figured out how to get zapped from a 9 volt battery. (No coil is involved). No this is not something I taught them..... Maybe one of you did. So maybe 9 volts is to much? Now are you going to tell me nothing over 1.5v?Why is it okay for you to get accidentlay zapped and not students?

author: Fungus
author_rank: Super Contributor
timestamp: February 07, 2018, 05:52:34 am
content: Quote from: DougSpindler on February 07, 2018, 05:38:18 amBecause we got zapped alone at home out of stupidity+ignorance, not in a classroom with somebody there to guide us and tell us not to do whatever stupid thing we were doing.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 07, 2018, 06:08:37 am
content: Quote from: Fungus on February 07, 2018, 05:52:34 amAhhhh and you think just because students are at school under the supervision of an teacher they are smarter than you at home. See that's the problem we are teaching these kids to be smart, but that doesn't mean they still don't do dumb thinks. (Notice I did not use the word stupid.) They would remain stupid if they did not go to school.

author: jacklee
author_rank: Regular Contributor
timestamp: February 07, 2018, 09:23:57 am
content: Quote from: DougSpindler on January 28, 2018, 07:50:52 amIn my personal opinion, students should have interests in touch screen scope, it is definitely creative! I think learning the oscilloscope theory with simple operations like Micsig TO1104 will make them more interested in oscilloscopes. I think people who have this scope will also agree with me.Here's their operation video you may give it a look:https://youtu.be/TsqLbc1AlmoI think for the reason you are a teacher, Micsig should also give you a good discounts, I think they should have discounts plan for students. Anyway, give it a try.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 07, 2018, 01:51:58 pm
content: Quote from: jacklee on February 07, 2018, 09:23:57 amI think you raise a good point there; newer generations are quite familiar with touchscreen interfaces, thus making micsig quite an attractive equipment -even if they dislike it, there's always a seed for an idea on how to make the interface better. Think about it: the mooshimeter is already attractive due to this very same interface.In my own experience, I am amazed at the dexterity that some of the younger engineers show in using the laptop's touchpad.

author: Fungus
author_rank: Super Contributor
timestamp: February 07, 2018, 02:49:43 pm
content: Quote from: rsjsouza on February 07, 2018, 01:51:58 pmThey're not common in the real world though, and not exactly within the $400 budget.

author: Old Printer
author_rank: Frequent Contributor
timestamp: February 07, 2018, 02:51:03 pm
content: Quote from: rsjsouza on February 07, 2018, 01:51:58 pmAnd my five year old granddaughter can run circles around me on my iPad/phone.

author: Fungus
author_rank: Super Contributor
timestamp: February 07, 2018, 03:04:02 pm
content: Quote from: Old Printer on February 07, 2018, 02:51:03 pmI bet she knows some pop songs you don't, too.Neither is a sign that she's a genius.

author: rsjsouza
author_rank: Super Contributor
timestamp: February 07, 2018, 03:04:16 pm
content: Quote from: Fungus on February 07, 2018, 02:49:43 pmI wasn't sure about the budget, but you raise a good point as well. "Real" labs don't use them very often, but I can see it happening in a way, shape or form in the future.I always wonder about the day when oscilloscopes will have a detachable touchscreen that can be used remotely à la Fluke 233 series (but with a full interface).Quote from: Old Printer on February 07, 2018, 02:51:03 pmMy daughters are starting to get smarter with gizmos like that as well... It won't be long before I start asking for their help.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 07, 2018, 03:50:57 pm
content: Ha! younger -electrical oopsie- funeral fodder youngsters swiping and pinching on toy touchscreens isn't real education, experience, intelligence nor diligenceThey'll end up in the ground, blinded and trash gear just as fastor fasteras the non-internet web destitute previous generation of button pushing dial turning prod blunderers they think are 'left behind or tech starved'Tip for old players: lift your game and catch up, or don't stress over it,either way don't let the current screen based toys and jargon BS hipstertards intimidate youThink about it: What could be more dumbass and mind slave compliant than having to gooogle, wiki, youtube and online purchase everything ?Who will really be on top in a SHTF scenario?>"Uh oh! no phone reception, no GPS, where are we, what's going on, -Web Server down please try again later-, 16% Battery Power left..."Welcome to old school SOL...

author: rsjsouza
author_rank: Super Contributor
timestamp: February 07, 2018, 04:44:56 pm
content: Our grandfathers to us:Ha! younger -electrical oopsie- funeral fodder youngsters rotating and pushing buttons on toy "multimeters" isn't real education, experience, intelligence nor diligenceThey'll end up in the ground, blinded and trash gear just as fastor fasteras the non-VOM digital destitute previous generation of rotating switches needle reading lever pushing prod blunderers they think are 'left behind or tech starved'Tip for old players: lift your game and catch up, or don't stress over it,either way don't let the current digital based toys and jargon BS hippietards intimidate youThink about it: What could be more dumbass and mind slave compliant than watching TV, have a phone on the pocket and order by mail everything ?Who will really be on top in a SHTF scenario?>"Uh oh! no TV signal, no dial tone, where are we, what's going on, -Off air please try again later-, No Electricity or hot water or ar conditioning..."Welcome to old school SOL...

author: DougSpindler
author_rank: Super Contributor
timestamp: February 07, 2018, 05:04:12 pm
content: Quote from: jacklee on February 07, 2018, 09:23:57 amI personally like touch screens, but they are horrible for teaching. When I or a student points to something on the screen settings change. I have to use a plastic a straw or something similar to use as a pointer for4 something on the screen.Just looked at the price..... About twice that of the Rigol. I would gladly purchse one but they would have a offfer a substatianl instructors discount.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 07, 2018, 05:11:47 pm
content: Quote from: Fungus on February 07, 2018, 02:49:43 pmTouch screens are very common in the real word. I prefer them over non-touch screens. Most of the computers own all have touch screens as does my my phone and the screen in my car But for test equipment I don't think they work so well. Just about all of you are telling me my students should be wearing gloves. Gloves and touch screens don't work well together. I don't think touch screens would ever work well on in the work place. (I'm sure there are a few exceptions.)

author: DougSpindler
author_rank: Super Contributor
timestamp: February 07, 2018, 05:20:58 pm
content: Quote from: rsjsouza on February 07, 2018, 04:44:56 pmPilots and airplane industry are having a similar issue. Old pilots learned how to fly reading analog clock type instruments. Most new planes are using "glass" or LCD screens. Same info, just presented in a different format. A number of fatal airplane crashes have been attributed to pilots who trained on one, being confused by the other.Wonder how many of our younger folks can read an analog meter? Or for that matter an analog clock?

author: rsjsouza
author_rank: Super Contributor
timestamp: February 07, 2018, 05:42:51 pm
content: Quote from: DougSpindler on February 07, 2018, 05:11:47 pmDoug, the types of gloves for electrical safety do not work on a great number of rotary dials either - that is why there are DMMs where the rotary is located on the side of its body, so they can be rotated with the thumb (Fluke 11x, Keysight U123x are examples).Gloves or not, however, can benefit from acapacitive stylus. I would even recommend for rotating virtual knobs and pushing buttons on an oscilloscope, given the precision is greatly increased.

author: Fungus
author_rank: Super Contributor
timestamp: February 07, 2018, 06:05:11 pm
content: Quote from: DougSpindler on February 07, 2018, 05:11:47 pmThey're allowed to take them off when they're not poking at AC mains.But maybe you're still planning on connecting your 'scope to mains once per day just to see if the electricity company is trying to sneak a triangle wave into your building.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 07, 2018, 06:36:58 pm
content: Quote from: rsjsouza on February 07, 2018, 05:42:51 pmThanks I learned something. Now I know why the dials are offset and have ridges. Makes perfect sense.Just looked at the Fluke 11x - It's been recalled.Gloves are no substitue for knowing exactly what you are doing. I remember the story of an electrician who had been marred for less than a year. His "new" wife felt strongly about the vows of marrage and made here new husband, (an electician) promise to never take his wedding ring off. (Hope you know were this is going.) The ring being larger than his fingers thinned the insuation in the glove. One day he was working on mains a was electrocuted to death.I would think the husband must have had a life insurance policy. So was the wife ingnorat or very clever?I never wear my wedding ring either. Inpart becuase of theis story, but more becasue of my own experiances. Years ago working with computers whihc had daugher boards in slots in intentiolay but stupiildy put my finger between to peripherial cards. When my gold ring hit the tracings on one card adn the chips on the other there was a litte bzzzt and some fireworks. Normal reaction is to pull one's had from a spark and I probably cut my finger on the traces. (Didn't get zapped that time.) But ever since that day I have never worn my wedding ring. I might be smart, but I realized wearing a wedding ring one beomces just too confortable and I will never rememeber to remove it when working with any electricity (Plus I would probably loose it too.) The other reason is my wife doesn't have a large life insurance policy on me so I'm worth more to her alive than dead.Guess what I'm saying no amount of protective gear is a substitute for propler education in safety when it comes to electrity. And even then safety equipment doen't always keep you safe.One more story. Had a boss who was wearing safety glasses. Somethign arced sending motlen metal in the air. One small spec of molten metal hit him in the face buring him. The trajectory of the meal was such that the path was beween the top of safety glasses and the skin of his forehead. As I reacl it hit hin in the eye causign a minor burn.Moral of the story - Never rely on safey equipment to protect you..

author: Fungus
author_rank: Super Contributor
timestamp: February 07, 2018, 08:11:45 pm
content: Quote from: DougSpindler on February 07, 2018, 06:36:58 pmIn other news: Smokingdoesn'tcause cancer. I know this because I had an uncle who smoked until he was 90.

author: Electro Detective
author_rank: Super Contributor
timestamp: February 08, 2018, 07:32:01 am
content: LOL, if safety glasses, gloves, and ear plugs may not quite cut it, what's left to protect the over confident 'empowered' stupdents?Ah yes I forgot..The Force

author: kcbrown
author_rank: Frequent Contributor
timestamp: February 08, 2018, 09:14:52 pm
content: Quote from: DougSpindler on February 07, 2018, 06:08:37 amI certainly agree with the sentiment that kids are far too shielded from the real world, to their detriment. Your intentions here are commendable. The problem is the approach.In essence, what you're saying is that you want the kids to learn from their mistakes. But what youreallywant is for them to learn, whether through their mistakes, through the mistakes of others, or through direct instruction.But you also want to keep your job, keep your assets, and retain your freedom, all within an environment which is highly litigious and in which people apparently desire their kids to be overly sheltered.This means that, if you need to set up an environment in which making mistakes is both possible and part of the learning process, you'll want to set it up such that there is no real possibility of actual injury arising from such mistakes. This means limiting the voltage and available current in anything the students might play with. You'll want both to be high enough to make the mistakes apparent and at least mildly unpleasant, but nothing more than that.Of course, prior to even that exposure, you'd want to instruct them in safe handling practices, etc., and perhaps even show them some videos that illustrate the dangers of getting it wrong. Which is to say, you give them the opportunity to learn from direct instruction first, then indirect experience (the videos) and then, only after that has been given, direct experience.Exposing the students to experimentation with mains voltages and available currents isneedlessexposure to risk, both for them and for you.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 14, 2018, 02:17:39 am
content: Quote from: Fungus on February 07, 2018, 08:11:45 pmWhat about the millions who did smoke and died very young from lung cancers, and pulmonary diseases? You might be interested to know tobacco is fertilized with radio-active Polonium and radio-active lead.https://www.reddit.com/r/askscience/comments/3jaitj/why_is_radioactive_fertilizer_used_on_tobacco/A smokers lungs receive far more nuclear ionizing radiation from tobacco smoke than people at Fukushima or Chernobyl.https://www.youtube.com/watch?v=TRL7o2kPqw0&feature=youtu.be&t=9m55s

author: IAmBack
author_rank: Regular Contributor
timestamp: February 14, 2018, 08:46:13 am
content: Quote from: DougSpindler on February 14, 2018, 02:17:39 amFunny thing, I've read somewhere that tobacco industry is the first victim of nuclear (weapon) industry (and tests)...

author: DougSpindler
author_rank: Super Contributor
timestamp: February 14, 2018, 08:56:55 am
content: Quote from: IAmBack on February 14, 2018, 08:46:13 amI don't think so..... But if you have additional information I would like to consider it.

author: donkey77
author_rank: Regular Contributor
timestamp: February 20, 2018, 09:52:05 pm
content: Have you killed off any of the students yet? Oh, and how's the scope going?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 21, 2018, 03:58:01 am
content: Quote from: donkey77 on February 20, 2018, 09:52:05 pmThanks for asking. Class is going really well. I've been trying to zap a student here and there but so far no success. Nest week I'll be talking about relays and solenoids so I'm increasing my odds someone will get zapped.I'd like to say this again. I really want to thank Dave for his videos and everyone here in the forums who helped me in deciding what scope to buy. I am very pleased with the Rigol DS1054Z. My only gripe is the text is a bit small for my eyes. But I think that would be the case with all of the scopes.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: February 21, 2018, 04:50:58 pm
content: Doug,1. Buying the DS1054Z for the class - great idea.2. Suggesting your students use the scope to probe 115V from an outlet - terrible idea.If you are teaching an electrical safety class then there is a lot of ground to cover, lethal voltages, arc flash, grounding, etc. and I don't think you have time to do all that. The best reason of all not to let them do that is that, if one of your students managed to kill themselves (a definite possibility IMHO), your ass would be in the fryer and you could lose everything - house, 401k, etc.So now you're thinking that I'm a do-it-by-the-rules boring old git eh? Try this, if you want to probe high voltages with your scope, cut the ground pin off your mains lead; now the ground on your scope will be floating. You could then fasten the live side of the 115 V to the ground on your scope and there will be no explosion, no fried PCB, no smoke from the ventilation holesIt works because the SMPS bricks are (almost always) isolated so there's no connection from input to output - you can prove this to yourself with an ohms meter.I do this all the time but I have a note on the front of my scopes reminding me that they're not grounded.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 21, 2018, 05:39:34 pm
content: Quote from: Gandalf_Sr on February 21, 2018, 04:50:58 pmI am a college professor who teaches computer networking, server administration, virtualization security and digital forensic investigations. . All of the classes I teach are advanced level classes.This semester I was asked to teach a college level class to high school students. (I actually have an 8th grader.). These kids are smart and are eager to learn. The class is an introduction to computers class and is suppose to teach them how to solve “business” problems with computers.I am taking the liberty since the course does not specifying what type of computer or programming language is to be taught in the class to use Arduino. Right now I have the studnets going through the standard labs. The business problem they are going to solve is to build a replica of an arcade game and learn how to hack it. (Actually the real arcade game is “rigged” so players who win only actually win 1 in 30 plays. The business problem I’m teaching them is games of skill may not.... They are rigged.So why the scope? It’s a real stretch for what I’m teaching. But these kids are smart and I am teaching them networking and computer protocols. I’ve already taught them how to use a multimeter (HarborFreight) to measure DC voltages and currents to determine the DC voltage and current of one mini-Christmas light from a string of 100 which is spec’d at 120 VAC, We actually found the bulbs could be run at 220vac.Since our college doen’t have the budget for every student to blow a channel in a scope I’m the only one that will be using it. I did watch Dave’s video on scope gnd fully understand what he’s talking about. The Arduino when connected with USB to a computer I’m sure are earth grounded. Something I’m always thinking about.I want to use the scope to show students the scope show voltages a multimeter can’t display. And then I would like to show them how to use a scope to “see” a protocol and to my +1 the Rigol has a decoder for the protocols Arduino uses. It would be really neat if it had the ability to decode an Ethernet frame. (But for that I have Wireshark.)My goal is to show these kids how hackers can hack ther Arduino projects by converts injecting traffic on the network buss. One of the projects I think I might have them make with the Arduinos because we have the IR module is the TV-B-Gone. Push a button and the Arduino sends out all TV off IR codes. (Nice little hacking project.)Will the kids be touching the mains? No, but them I’m not watching them 24 hours a day. Will I teach them mains safety? Yup.Will I be attaching the scope to the mains? I was thinking about it. But in my “junk” box I remember I have a doorbell transformer. 120 VAC to 24 VAC. Perfect for displaying a sine wave. Transformer not only steps downl, but isolates. Thank you some one in the forums who suggested that.Quick question on the scope. I seem to remember being taught that scope can display current over time. With the Rigol scope I have can I display current? (Or am I mistaken?)Thanks.

author: Fungus
author_rank: Super Contributor
timestamp: February 21, 2018, 06:43:30 pm
content: Quote from: DougSpindler on February 21, 2018, 05:39:34 pmThe 'scope can't measure current directly, only voltage.You can see current if you pass it through (eg.) a 1 Ohm resistor then measure the voltage across the resistor.(aka a "current shunt")

author: DougSpindler
author_rank: Super Contributor
timestamp: February 21, 2018, 07:33:39 pm
content: Quote from: Fungus on February 21, 2018, 06:43:30 pmIs a special probe needed? For AC you could use an inductive coil. But for DC?

author: Fungus
author_rank: Super Contributor
timestamp: February 21, 2018, 07:50:16 pm
content: Quote from: DougSpindler on February 21, 2018, 07:33:39 pmNo, it's just Ohm's law.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 21, 2018, 07:53:26 pm
content: Quote from: Fungus on February 21, 2018, 07:50:16 pmUnderrdtood. Somthing I'm going to need to researh if I ever need to do it.

author: Fungus
author_rank: Super Contributor
timestamp: February 21, 2018, 08:24:56 pm
content: Quote from: DougSpindler on February 21, 2018, 07:53:26 pmYou need to research Ohm's law?

author: ebastler
author_rank: Super Contributor
timestamp: February 21, 2018, 09:30:28 pm
content: Quote from: Gandalf_Sr on February 21, 2018, 04:50:58 pmAnd all those exposed ground shields on the scope's BNC connectors, and your probes' ground clips which are dangling around, would be atwhatpotential exactly?

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: February 22, 2018, 12:00:32 am
content: Quote from: ebastler on February 21, 2018, 09:30:28 pmI didn't say that you couldn't kill yourself, I said you wouldn't let the magic smoke out of your scope. Pay attention.

author: ebastler
author_rank: Super Contributor
timestamp: February 22, 2018, 06:22:31 am
content: Quote from: Gandalf_Sr on February 22, 2018, 12:00:32 amAs it happens, a large part of this thread is about how to avoid killing yourself, and even more importantly, avoid killing your students. And your post was giving advice on that matter, it appears.And to make sure everybody realizes how cool you are, you had to point out this dare-devil approach you are taking to scope measurements. I am pretty sure you are not a teenager, but this behavior is worthy of one. Or maybe, if they ever produce a "Jackass" episode for nerds...

author: DougSpindler
author_rank: Super Contributor
timestamp: February 22, 2018, 05:18:20 pm
content: Quote from: ebastler on February 22, 2018, 06:22:31 amYou folks keep saying I or one of my studnets is going to get killed. Yet no one can site even one case where a student school was killed in an electronics class. Or for that matter even seriously injured.

author: Gandalf_Sr
author_rank: Super Contributor
timestamp: February 22, 2018, 07:05:34 pm
content: Quote from: ebastler on February 22, 2018, 06:22:31 amThanks for those kind words oh flawless one.With the caveat that you have to know what you're doing, there are some occasions where having no earth on your scope power lead has advantages - as long as you're aware of the pitfalls. I bet you I'm not the only EE that's ever cut the earth probe off a power leads for scope use.

author: ebastler
author_rank: Super Contributor
timestamp: February 22, 2018, 07:15:53 pm
content: Quote from: Gandalf_Sr on February 22, 2018, 07:05:34 pmI love you too, my daredevil.

author: ebastler
author_rank: Super Contributor
timestamp: February 22, 2018, 07:17:02 pm
content: Quote from: DougSpindler on February 22, 2018, 05:18:20 pmThat may be due to the fact that such classes are mostly led by teachers with a different approach than yours.Seriously: Yes, you have to be unfortunate to kill yourself with 115V. But what if you have a student in that class who has a pre-existing heart condition, probably without even being aware of it? Do you really want to take that risk -- morally, and looking at the impact it might have economically on the remainder of your life?When doing a proper risk assessment, you multiply probability (very small here) with impact (fatal). I can't find a freely accessible copy of the risk matrix e.g. in IEC 61010, and don't have our copy handy -- maybe someone can help out with the details. But if you have identified a certain risk with a fatal outcome and want to argue that you can simply live with it, the tolerable probability according to that standard is awfully small; certainly less than one in a million, from memory.When thinking about the probabiity aspect, consider the impact you will have on the way these kids will approach mains electricity for the rest of their life. "Hey, no need to search for an isolated screwdriver. Remember, Doug even showed us how he could quickly touch that life lead with his fingertip!"The warnings from several different forum members are very much well-intended and heartfelt. Please don't read them as arrogant "I know about electrical safety and you don't" statements. These are serious concerns about a very unlikely, but fatal risk.

author: Fungus
author_rank: Super Contributor
timestamp: February 22, 2018, 07:54:06 pm
content: Quote from: ebastler on February 22, 2018, 07:17:02 pm(image should be viewed at full res. to truly appreciate it)

author: DougSpindler
author_rank: Super Contributor
timestamp: February 22, 2018, 08:00:42 pm
content: I'm not saying 120 or 240 can't kill. I'm just asking if in a classroom environment if it ever has? Football yes, baseball yes, basketball yes and even auto accidents on school grounds yes. But an electrocution death in an electronics class? Don't think so. I'm more concerned about my students being shot while in the classroom than getting serious hurt or dying from being electrocuted.

author: Fungus
author_rank: Super Contributor
timestamp: February 22, 2018, 08:04:24 pm
content: Quote from: DougSpindler on February 22, 2018, 08:00:42 pmThere was a first football death, a first baseball death, etc. I'm sure the coach wasn't expecting it.It's also about attitude. Electricity should always be treated with respect, safe practices followed. I don't see how you can justify not doing it.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 22, 2018, 08:13:09 pm
content: Quote from: Fungus on February 22, 2018, 08:04:24 pmWhen did I ever say I'm not treating electricy with respect or not teaching my studnets electricy safety. You folks are all saying a kid getting zpped with 120 is going to kill them. I'm just asking for one exapmle of were it has bapped.I stated previoully when I was in school, and I'm sure many people in the fourms have been zapped. It's all just part of learning. Yes we know what we are doing but accidents do occur sometimes. Even Dave said he had a multimeter blow-up in his hand. Is he dead, did he get seriouly hurrt or burned..... Nope.Yes treat electricty with respecct, but no need to scare people about it either?

author: Dubbie
author_rank: Unknown
timestamp: February 22, 2018, 08:24:15 pm
content: According to this article:http://www.ecmweb.com/content/case-120v-electrocution-mysteryIn 1999, 278 workers died from electrocution.1/3 were high voltage incidents, the remaining were 120VIf you want to contribute to the next generation of statistics, go ahead. I will judge you as a fool though.The reason there are no readily available examples of students being electrocuted is that there are very few educators moronic enough to expose their students to unnecessary risks.

author: kcbrown
author_rank: Frequent Contributor
timestamp: February 22, 2018, 08:36:13 pm
content: If the risk is unnecessary and, as here, doesn't even give you any advantages at all, then why in the world would you take it anyway? Surely that would be irrational, no?Sent from my iPhone using Tapatalk

author: ebastler
author_rank: Super Contributor
timestamp: February 22, 2018, 08:42:06 pm
content: Quote from: DougSpindler on February 22, 2018, 08:13:09 pmFirst, I don't think anybody suggested that it "will" kill them, or even that it is likely to do that. The point is that, while it is very unlikely to be fatal, it isnot unlikely enoughto justify that you simply accept this possibility.Given the most severe potential outcome -- death of someone you have taken responsibility for -- you need to do more to minimize the probability even further, to make the probability * severity product acceptable.QuoteGiven the odds and the asymmetrical outcome, how can you propose this "learning gamble" to your students, their parents, and the school?If 1000 students learn a valuable lesson (and another 1000 forget it right away, and another 1000 become even more reckless with electricity), and one is left dead in the process, would you consider that OK in the balance? What multiplier on the positive outcomes would it take to make you say "Sure, it killed one of them, but look at the valuable lesson many of the others learned." ?!

author: Fungus
author_rank: Super Contributor
timestamp: February 22, 2018, 09:12:44 pm
content: Quote from: DougSpindler on February 22, 2018, 08:13:09 pmWhen I'm teaching I always treat it with 10x normal respect because I know for a fact that pupils only absorb a small fraction of anything a teacher says.

author: ArthurDent
author_rank: Super Contributor
timestamp: February 22, 2018, 09:37:00 pm
content: Let me summarize this thread. We have someone who describes himself, at best; as a tinkerer who has been teaching cybersecurity as a college professor in classrooms for 15 years; who wants to teach hands-on electronics to children; who believe that safety is optional; but freely and continually spouts his political views throughout his posts; and is unwilling to listen to others with experience who have explained in detail the flaws in his ‘method’. To excuse the pun, I think this class is beyond his scope.Experience isn’t the best teacher because you get the exam first then the explanation after and suggesting measuring line voltage with a scope with his skill level is just idiotic. I am thankful he didn’t decide to teach firearms safety.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 23, 2018, 04:22:55 am
content: Quote from: Dubbie on February 22, 2018, 08:24:15 pmAmazing, why have there been no deaths since 1999? That's incredible.But here's the real question, why 278 professionals die from electrocution? Were they not trained properly?How do these students learn? I've seen suggestions to teach students who will be working with high voltage using low voltage. Are you suggesting they learn how to work with high voltage on the job? I can't imagine any employer would hire anyone to work on high voltage that's never been exposed to high voltage before.Why would you not want students to learn how to work with high voltage in a controlled safe environment where they are being closely monitored?Again I will ask has there ever been and electrocution death or serious injury

author: Dubbie
author_rank: Unknown
timestamp: February 23, 2018, 04:50:06 am
content: Of course there have been deaths since then. That was the statistic cited in the paper. Thankfully the yearly death toll has been decreasing. This has been attributed to better education, better standards and regulations and new technology such as RCDs.As to your last question, I answered that already. There are very few teachers foolish enough to let students get “educational zaps” so therefore, students don’t die. See how that works?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 23, 2018, 05:05:36 am
content: Quote from: Dubbie on February 23, 2018, 04:50:06 amSorry I don't. I think you will find at many science museums educators let children get zapped. I know when I was in school many of the students were curious about electricity and zapped themselves. A popular science project at schools is a zapper. (Home made step-up transformer.)This is called learning. Are you trying to tell me you have never been zapped?

author: Dubbie
author_rank: Unknown
timestamp: February 23, 2018, 05:38:31 am
content: Stop being deliberately dense. A high voltage current limited zap like a stun gun or electric fence is not comparable to a mains shock with the potential to supply tens or hundreds of amps of current.

author: DougSpindler
author_rank: Super Contributor
timestamp: February 23, 2018, 06:31:00 am
content: Quote from: Dubbie on February 23, 2018, 05:38:31 amDude do you really think student in a classroom would have access to mains with tens or hundreds of amps of current? You obviously do which is why you said it. Maybe that was the case where you went to school, but that's not the case in my classroom.

author: kcbrown
author_rank: Frequent Contributor
timestamp: February 23, 2018, 07:44:13 am
content: Quote from: DougSpindler on February 23, 2018, 06:31:00 amWhat amount of current are the power sockets in your classroom rated for, and what are the breakers set to trip at? If it can power a typical hair dryer then you're looking at 10 amps or more.So I'm REALLY skeptical of your claim that the mains sockets in your classroom can't source current in the 10 amp or greater range.Sent from my iPhone using Tapatalk

author: Fungus
author_rank: Super Contributor
timestamp: February 23, 2018, 10:49:53 am
content: Quote from: DougSpindler on February 23, 2018, 06:31:00 amWho cares? There simply shouldn't be bare pieces of metal around the place that are connected to AC mains. It's not necessary. The quality of teaching won't improve because of it, you're not "preparing them for the real world" in any way.I really don't see why that's difficult to understand.

author: ebastler
author_rank: Super Contributor
timestamp: February 23, 2018, 02:52:47 pm
content: Seems to me that we can end the discussion at this point. DougSpindler has dug in his heels so firmly, I would be utterly surprised to see any of our arguments getting through.Good luck, Doug. Before you start the class, I recommend full disclosure of your "learning through painful experience" concept to the students, parents, and school; I'm sure they will be delighted. And while you have their attention, make them sign waiver forms...

author: DougSpindler
author_rank: Super Contributor
timestamp: February 23, 2018, 04:29:25 pm
content: I've been teaching for over 20 years so it's not like you are going to change my mind or the way I teach UNLESS there is a reason I should do something different.While I appreciate everyone's input my students are the product I'm producing. Many have told me they like my teaching style and appreciate the real world lab exercise situations I give them.In my 20 years+ of teaching not one of my students has died or been serious injured. Yes a few over the years have been zapped but no permanent or long term injuries.Over the years I have had a few students who tell me EMI/RFI cause brain cancer, and a wide variety of other diseases. They have even brought me books, which I have read and researched and found all of the research to be less than credible.You "guys" keep saying someone in my class is going to get killed, yet no one can provide even one case of where a student was killed in an electronics class at school. Yes electricity is dangerous and needs to be treated with respect but there's not need to scare people about it.

author: donkey77
author_rank: Regular Contributor
timestamp: February 23, 2018, 08:43:11 pm
content: Part of me thinks that you, Doug, are just trolling and you are actually the age of these students you say you teach.If not I'm pretty scared that people like yourself can be allowed to teach with the attitude you have. Putting the safety concerns aside for a minute the mixture of lack of knowledge, teaching by some youtube video and the lack of basic spelling and punctuation, I feel you are doing your students a dis-service. Add in the stubborn arrogance that you have shown to those, in my opinion, better qualified than yourself, makes you a liability to those in your care.I would be interested how you would feel showing this thread to your superiors at the school/parents, and what their opinion is regarding letting you loose on their children/students!

author: Someone
author_rank: Super Contributor
timestamp: February 23, 2018, 11:01:08 pm
content: Quote from: donkey77 on February 23, 2018, 08:43:11 pmAnd thats the simple point, an academic would be happy to have their work critiqued and shared publicly but this person wont disclose their affiliations, qualifications, or faculty where they are supposedly teaching.Are there any members in the bay area of the US willing to spend a little time on the phone calling around? It should be easy enough to verify their current employment.

author: Someone
author_rank: Super Contributor
timestamp: February 23, 2018, 11:13:00 pm
content: Quote from: DougSpindler on February 23, 2018, 04:29:25 pmIts a high risk environment with a small number of people in it, just like the US claimed proudly for a long time they never lost an Astronaut in space. That doesnt make space travel safe, and mains power is known to be dangerous with students in schools being killed without even entering the additional risks of an electronics class.You can't prove no student has ever died in an electronics class, while we can prove students are dying from exposure to mains power. Its these ridiculous "arguments" you put which make you claim of being a serious/experienced teacher laughable, basic logic can quickly disassemble your points and reduce your arguments to misguided hubris .Quote from: DougSpindler on February 23, 2018, 04:29:25 pmTeaching electronics for 20 years and still don't understand the basics of measurement technology? Sounds like you've been teaching unrelated courses for many years and assume you can apply that experience to an unrelated field (which has real and immediate physical dangers to the students). If you're so confident in your teaching and coursework and have the support of your peers and faculty why wont you reveal who they are?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 24, 2018, 03:54:35 am
content: Quote from: Someone on February 23, 2018, 11:01:08 pmIntereitng comment from someone who hides behind the name "someone". Is there a reason you don't use your real name? At least I use my real name and have told you where I teach and live. Any reason you fail to do the same?Silly "someone", I'm teaching at a public college my name, teaching qualification and where I teach are all a metter of public recored.If you would stop bashing teahcers you would find I am an award winning instructor and two of my students have been recogined for their acheivments (what I taught them) by the Preseidnt of the United States.Can you say the same? Or are you one of those people that just goes arond basing teachers who do a good job?

author: Someone
author_rank: Super Contributor
timestamp: February 24, 2018, 06:31:58 am
content: Quote from: DougSpindler on February 24, 2018, 03:54:35 amBut you wont share this information when asked (now several times)?

author: Electro Detective
author_rank: Super Contributor
timestamp: February 24, 2018, 09:52:52 am
content: Quote from: DougSpindler on February 24, 2018, 03:54:35 am'Doug' your comment above has to be some sort of record here at this forum for sudden grammar gone southSorry to be 'that guy' to point it out, but just look at itDid somebody accidently spill vodka or grappa onto the keyboard while the speech recognition program was running?

author: DougSpindler
author_rank: Super Contributor
timestamp: February 25, 2018, 05:14:03 pm
content: Quote from: Electro Detective on February 24, 2018, 09:52:52 amYou do have a valid point. My reply was written on a small screen device, with a funky auto-correct/spell checker while I was driving my car. To pay homage to Mark Twain.... I’m sorry I did not have the time to make my post shorter of correct the spelling pr grammar.But here’s the think... does it really matter? “Someone” has become a troll and has an agenda which apparently included bashing instructors and has nothing to do with the original post or subsequent questions. If “someone” were posting serious meaningful posts I would take the take to provide grammatically correct responses.I will say this again, I really would like to thank those whol provided meaningful quality responses to my original question. I might be an instructor/profesor but I tool am always learning. Most of the folks here have given me wonderfull information which I’ve already used in my classroom and on conference calls with other instructors so they will teach their studnets.As i stated previously it’s been decades since I have used a scope so being a buy one to use as a demonstration device in the classroom will be a real treat for my studnets. I teach computer networking so now I will be able to show my studnets the actual network signals and even decode one or two.What “someone” may not understand is when one works with networking equipment one is not always working with low voltages. Studnets are working wth 48 vdc and mains or 120/208 and 220vac.For the past 20 years the $8,00 eBay multimeters have been fine. (Although someone is telling me they aren’t safe and one my studnets is going to get killed). Well that has not happened. In all my years of teaching I have never had even one student get seriously injured. Worst injury is getting poked with a screwdriver, getting pinched with a pair of pliers or getting zapped. I think the worst injury I have seen in 25 years in a technology class is a paper cut. Now I’m sure someone is going to say I’m irresponsible for using paper in my class and that a studnet could die form getting cut and infected. Yes that is possible and I am sure it happens but the reality is many of these kids if they were not in school would be doing other things more risky LSU he as stealing copper wire from street lights in our campus parking lot. (Yup, that has happed 3 times so far). At least if they take my class they will be able to use a voltage probe and multimeter to test the wire to see if it is energized befor they cut it. I think this would make someone happy knowing I might be saving the life of a thief who is stealing copper wire.

author: rogermanlleu
author_rank: Newbie
timestamp: February 25, 2018, 07:12:01 pm
content: Be careful, a wire might not have "voltage", i.e. being at earth potential, until you cut it! I suspect many copper thieves have died cutting the neutral wire of a live circuit.

author: The Soulman
author_rank: Super Contributor
timestamp: February 25, 2018, 07:47:27 pm
content: Quote from: DougSpindler on February 25, 2018, 05:14:03 pmI don't like to insult people but I'd call you one irresponsible individual (at best).

author: nctnico
author_rank: Super Contributor
timestamp: February 25, 2018, 08:34:46 pm
content: Quote from: The Soulman on February 25, 2018, 07:47:27 pmUnfortunately people texting while driving usually don't drive their car into a tree.Note to self: when in the US find Doug and zap him ten times!

author: Simon
author_rank: Unknown
timestamp: February 25, 2018, 09:11:54 pm
content: Well I think if Mr Spindler has not learnt what he needs to know sofar no more discussion will make any difference anyway. I think it's time to draw this one to a close.