hybridfree/eevblog-posts huggingface dataset:
shottcky diode switching speed - Page 1
Forum section: electronics / beginners

author: alireza7
author_rank: Regular Contributor
timestamp: November 03, 2017, 05:57:15 pm
content: hias far as i know shottcky diodes are faster than pn junction diodes. why is this so?is that because they use a metal and a N junction and the major carrier are just electrons ?so if i have a metal and P junction shottck it would be slower than metal and N junction type (with the other parameters the same) because major carrier would be holes and holes have lower mobility than electrons?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 03, 2017, 07:30:28 pm
content: If it's majority carrier, there's no time penalty. Sooner or later, the holes recombine with electrons, whether in the P-bulk (if it's thicker than a few diffusion lengths) or the metal contact (if closer). (Note that a metal contact is a schottky junction too, just an ohmic, rather than rectifying, one. Work function and band levels determine this.)Indeed, isn't it that you can only make a schottky with P semiconductor, because metal is N (it's literally swimming with electrons)? It's been so long that I forget these things...On the practical side, real schottky diodes do have speed limitations, due to transit time, capacitance, and guard rings (which are standard PN junctions surrounding the schottky junction, to feather out the electric field and provide avalanche capability, giving higher reverse voltage ratings while making them reliable to handle and use). Particularly in high voltage diodes (where the forward voltage drop is higher), the guard ring can become forward biased, which will then exhibit reverse recovery during turn-off.Tim

author: rfeecs
author_rank: Frequent Contributor
timestamp: November 03, 2017, 07:53:08 pm
content: When a PN junction diode is forward biased, holes flow into the N side and electrons flow into the P side. They are minority carriers. When the diode bias is switched from forward to reverse, the minority carriers can still flow, so it takes extra time to remove these carriers. This is the reverse recovery time.A Schottky diode's operation doesn't involve minority carriers. So it doesn't require the extra time to remove them when it switches. That's why it's faster.P type Schottky would have higher bulk resistance than N-type with the same doping and size, etc. So the RC time constant might be worse for P type. But there are lots of factors, like barrier height, ohmic contact resistance, etc.
Should an anti-static "conductive" brush register on the DMM? - Page 1
Forum section: electronics / beginners

author: Giddie
author_rank: Contributor
timestamp: April 03, 2013, 08:58:55 am
content: Hi guys,I just bought these inexpensive "anti-static conductive ESD" brushes on Amazon:http://www.amazon.co.uk/gp/product/B00880B9FOMy question is this: they're all black, which suggests carbon and conductivity to me. However, I get zip on the multimeter. Absolutely no conductivity at all, anywhere. Should I expect this? Will it only conduct at high voltages? Is there any way to test that it will indeed conduct away to earth any generated static charge (through me, if I'm earthed)?

author: amyk
author_rank: Super Contributor
timestamp: April 03, 2013, 09:37:47 am
content: According to the description they use "dissipative polypropylene", and their resistance isveryhigh.http://www.plasticsintl.com/esd.htm

author: Giddie
author_rank: Contributor
timestamp: April 03, 2013, 10:02:41 am
content: Thanks, so it looks like although the resistance is high, it's enough to dissipate static charge. I'm thinking I'm earthed via a 1M? resistor already... But I guess there'll still be enough current to avoid charge building? I get pretty decent results from these brushes for cleaning off flux and general cleaning, and this was the only thing worrying me.

author: EEVblog
author_rank: Unknown
timestamp: April 03, 2013, 10:14:14 am
content: IIRC the handle on mine is conductive at some readable level on a regular meter. Will have the check the bristles.

author: Giddie
author_rank: Contributor
timestamp: April 03, 2013, 10:24:29 am
content: Using an Extech EX330, FYILove it, but I have bunged a bit of bluetack over the beeper because I found it too loud to use the continuity tester comfortably.

author: babysitter
author_rank: Frequent Contributor
timestamp: April 03, 2013, 11:27:32 am
content: Seems someone needs to measure with a high-resistance meter. I don't even have the brush.Additionally, Polonium-210 radiation sources are used on some antistatic brushes too.
Should capacitors below 1uF test give a 'bump' in continuity? - Page 1
Forum section: electronics / beginners

author: thared33
author_rank: Contributor
timestamp: April 07, 2024, 03:39:49 pm
content: As far as I know, you can do a quick, but definitely not thorough test of a cap with a multimeter by testing its legs with a continuity or resistance setting. You'll get a slight bump, then you can switch the leads and you should get another slight bump, both times going back to OL. And if you aren't getting something crazy low on the meter it means you don't have a short either. That's how I know it.So I'm diagnosing something that I just recapped and the only cap that doesn't give me any beeps is a .001uF polyester film cap. Is it normal for a cap that low in value to not give a beep or any hint of continuity? I have no spare caps in that value to test with.

author: wasedadoc
author_rank: Super Contributor
timestamp: April 07, 2024, 04:13:19 pm
content: Yes, normal. The transient is too brief for almost any DMM to sense.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 07, 2024, 04:16:19 pm
content: There is no "normal": meters have an unlimited range of thresholds for what they think is "continuity", and for how long until an indication is made (tone, light or value).Generally, they test by applying a small current and measuring the voltage, plus some propagation delay, filtering, or sample rate; whether any visual/audible alert results, depends on how long the capacitor voltage remains below threshold.One could imagine a meter that applies AC of variable frequency, and determines it's a capacitor and auto-ranges to the respective value, before reading it as continuity at all. Maybe that wouldn't be a very useful "continuity" range, but, I've seen some prettydubiouscontinuity modes before, I can assure you this is not beyond the realm of possibility.Approaching it in the other direction: for a given meter, if it tests by DC current, and has some response time (not necessarily deterministic, i.e. there is some internal sample rate not correlated to the moment when a resistance is connected, so we get a distribution of times from connection to indication, rather than a fixed time delay), then there will be a correlation between how long (or if at all) an indication is made, and the value of the capacitor. (And if not deterministic, then some probability of how long the indication lasts.) It seems your meter is capable enough to read even fairly small capacitors in this way; that's generally a nice feature.Tim
Should I add a boost converter - Page 1
Forum section: electronics / beginners

author: jrozner
author_rank: Contributor
timestamp: October 21, 2017, 02:19:44 am
content: I'm designing a board for an event that is powered off a cr123a. The batteries put out ~3v. The components that are on the board expect to run somewhere around 3.3v but have happy run on the ~3v from the cr123a with no problem. From testing the battery runs the board perfectly fine for around 12 hours until the voltage drops too low. Is a boost converter worth adding to bring the voltage up to 3.3v? Will I get significantly more time out of the battery with one? And what else should I consider with respect to deciding. The cost of adding the components is not an issue and we'll be building a few hundred of these to hand out to event attendees.

author: Awesome14
author_rank: Regular Contributor
timestamp: October 21, 2017, 02:46:00 am
content: At 3.00V, a cr123 battery is practically dead. If the board is happy with 3.00V, I don't think you're going to do much better with a buck boost circuit.

author: Ian.M
author_rank: Super Contributor
timestamp: October 21, 2017, 04:12:26 am
content: I beg to differ, as a CR122A smends most of its life below 3V on-load. Seehttp://panda-bg.com/datasheet/1617-360405-Lithium-Cylindrical-Battery-GP-CR123A.pdfUnless your board is *very* low powered, or is OK running down to around 2.5V, it will probably need a boost converter to get the best use out of the battery. Set the output as low as you can reliably run at so it only kicks in once the voltage drops, and make sure its quiescent current when the output is above its setpoint is very small compared to the load current
should i add a reverse bias diode to a fan on a power supply im building - Page 1
Forum section: electronics / beginners

author: nomad2415
author_rank: Newbie
timestamp: November 03, 2017, 03:24:38 am
content: Hi, I am currently waiting for parts to build a Dc power supply from this schematic:I got the design from this YouTube video:I am planning to rewind a MOT (microwave oven transformer) for the 21 volts but i have 120 volts main so i will just wind it till i get 21 volts.the main step down mentioned in the schematic is thishttps://www.ebay.com/itm/DC-DC-CC-CV-Buck-Converter-Step-down-Power-Supply-Module-7-40V-to-0-8-35V-8A-FE/331433779821?hash=item4d2afe226d:g:NzQAAOSwDwtUpmRPso anyways i didn't want to buy a fan because i have a fan from a microwave that runs off 120v normal US main power.the fan looks just like thishttp://www.oddmix.com/motor/px/mot_ac_ohsung_oem_1004x1.jpg.my question is because i will run this in parallel to the dc power supply, when i switch off the fan will there be a significant enough inductive spike to destroy the caps or the buck convert.also is there anything else wrong with this circuit that i miss.thank you.

author: ebclr
author_rank: Super Contributor
timestamp: November 03, 2017, 04:55:12 am
content: Transformers does not work with DC, You fan transformer is connected on the wrong placeIf you used the transformer symbol wrongly, for a dc-dc converter you don't need that diode because they are already there on the converter

author: nomad2415
author_rank: Newbie
timestamp: November 03, 2017, 03:53:33 pm
content: sorry here is an updated schematic although i now know that i dont need a diode for the fan.

author: ebclr
author_rank: Super Contributor
timestamp: November 04, 2017, 05:42:10 am
content: Those 2 diodes after the rectifier bridge are unnecessary, the Bridge symbol is wrong
Should I buy this Fluke 87V? - Page 1
Forum section: electronics / beginners

author: eKretz
author_rank: Frequent Contributor
timestamp: April 24, 2013, 06:31:02 pm
content: Hi all, there's a Fluke 87V advertised for sale.near me at $225 USD that is brand new in box also with the TL81A test lead set. Is that a good set of leads? I think it sounds like a great deal, but wanted to make sure before taking the plunge.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: April 24, 2013, 07:06:05 pm
content: heyassuming you have the need for 0.05% multimeter . yes that's awsome deal . go for itthis meter is going to serve you decades , you'll never regret it

author: eKretz
author_rank: Frequent Contributor
timestamp: April 24, 2013, 07:52:26 pm
content: I am starting to do more electronics stuff, working on board-level/SMD stuff so I think it could come in handy in the future. My current MM is a Fluke 117, but I only have the basic 2 leads for it. I really like the TL81A test lead set, it will make things a lot easier for working on boards/SMT, etc. I tried measuring voltage on some tiny transistors while diagnosing an electronic computer steering wheel and accidentally shorted two legs...watched the transistor put on a mini light show as it cooked. The little protected pin leads should be very helpful for that!

author: Unknown
author_rank: Unknown
timestamp: April 24, 2013, 07:58:21 pm
content: Yes, the TL81A is a nice set of leads. I quite like the TL71 probes and grabber hooks.

author: Fsck
author_rank: Super Contributor
timestamp: April 24, 2013, 08:11:50 pm
content: I'd grab it, assuming you get to inspect the meter first

author: eKretz
author_rank: Frequent Contributor
timestamp: April 25, 2013, 05:57:55 am
content: Snapped it up, looks fantastic and checks out good. I got the TL81A lead set and also some extra alligator clips and leads. And a bonus K-type thermocouple. Thanks for the reassurances!

author: cwalex
author_rank: Frequent Contributor
timestamp: April 25, 2013, 07:02:21 am
content: Quote from: eKretz on April 25, 2013, 05:57:55 amNice scoreI'm jealous

author: EEVblog
author_rank: Unknown
timestamp: April 25, 2013, 07:28:31 am
content: Quote from: eKretz on April 25, 2013, 05:57:55 amThat's pretty much a bargain then, nice score.

author: eevblogfan
author_rank: Frequent Contributor
timestamp: April 25, 2013, 07:37:20 am
content: heyfor that matter I bought pomona mini grabber , I should buy some micro grabber as well though , but any way . It'll help you grabbing those small leads no problem . good luck and have fun with your new superb meter

author: eKretz
author_rank: Frequent Contributor
timestamp: April 25, 2013, 07:42:28 am
content: Thanks!, I will check into those grabbers!

author: blewisjr
author_rank: Frequent Contributor
timestamp: April 25, 2013, 01:43:51 pm
content: I say go for it. I ended up getting one brand new off EBAY for $217 just could not pass it up. After shipping it came to around $230 usd can go wrong there. This thing will last me a lifetime.
Should I buy this HP/Agilent 33120a???? - Page 1
Forum section: electronics / beginners

author: ticktock3t
author_rank: Contributor
timestamp: November 18, 2012, 05:05:38 am
content: Hi, I'm a university student majoring in EE. I've been looking for a function generator for a while now to complete my lab set-up. This guy on craigslist is claiming to be selling a practically brand new 33120a function generator with all the cables and everything. I would really like to have this unit because it's the same model that I use at school and I am familiar with it. However, i'm worried that it's overkill for someone who's only starting his EE career. Other cheap-o models that i've looked at go for around $150-$250+ without many features or much else. The seller originally wanted $750 but I offered him $430 which he said he would accept. Would this be too much for me or is it a good buy?Pics of the function generator:http://imgur.com/a/iXhbk#0

author: EEVblog
author_rank: Unknown
timestamp: November 18, 2012, 07:41:10 am
content: That's a good price. Whether or not you should spend your limited funds on it, only you can answer...Look at it this way, you won't ever really lose money on it, you can always sell it easily on ebay for the same or more.You can also get a brand new Rigol 20MHz DG1000 ARB for the same price, or a lesser name 20MHz Siglent for under $300.Dave.

author: saturation
author_rank: Super Contributor
timestamp: November 18, 2012, 03:31:18 pm
content: When I was in school, I spoke to the Chair of the Physics department to be allowed to work in the lab so I could use gear, for free. In return I would help around the lab with inventory, cleaning, etc., gives access to things you have no space to store, or worse, get stolen.

author: Unknown
author_rank: Unknown
timestamp: November 18, 2012, 03:44:27 pm
content: It's a good instrument and a decent price. The Rigol DG1000 series is better in some ways, worse in others. One step down would probably be the ~$150-200 DDS function gens without advanced features like arb or modulation. As Dave already said, it's up to you to decide how much funds you want to allocate to a function gen at this stage in your career.
Should I connect the RF connector ground to the case ? - Page 1
Forum section: electronics / beginners

author: xani
author_rank: Frequent Contributor
timestamp: September 20, 2019, 12:32:14 pm
content: So I'm beginning to prepare a case for my LimeSDR, I chose just a simple aluminum extruded one and have few questions about grounding. I assume the case itself should be grounded to the USB ground but for the faceplate with connectors is it better to have something likehttps://discourse.myriadrf.org/uploads/default/optimized/1X/9bf555e8e6a4a5656ddcec7b58b30bd79ff31d3d_2_300x225.jpg(so just PCB with holes), or just drill holes in metal faceplate and have the connector's ground connected to the chassis ?
Should i get Fast or Slow fuses for a linear PSU ? - Page 1
Forum section: electronics / beginners

author: bingo600
author_rank: Super Contributor
timestamp: October 24, 2020, 06:38:06 pm
content: I just got a lot of these "Bulgin Source 12-1.7-10" - 12v 1.7A linear PSU's (NOS) $4/pcsThey look 100% like TDK-Lambda HSB12-1.7https://www.eevblog.com/forum/chat/what-did-you-buy-today-post-your-latest-purchase!/msg3287752/#msg3287752Datasheethttps://docs.rs-online.com/0aed/0900766b803dffda.pdfI'm going to use them for some OCXO'sThey need a 250mA fuse (250v) , but should i get Fast or Slow fuses ??My gut says Slow .. I was thinking startup (Capacitor charge)But i have no experience w. getting the right fuse for a linear PSU.TIABingo

author: Benta
author_rank: Super Contributor
timestamp: October 24, 2020, 08:37:49 pm
content: Slow.The mains fuse is not really for overload protection, but rather for fire protection in case of a catastrophic fault. Fast fuses would give you a steady job replacing them
Should I invest in a ESR Tester? - Page 1
Forum section: electronics / beginners

author: VladKEasternTiger
author_rank: Regular Contributor
timestamp: March 05, 2010, 01:51:07 pm
content: Hi everyone, okay I was told to invest in a ESR Meter, the cheapest ones in my country go from around £50 about 80 US Dollars to 100 $I know they are not cheap but I was told to check lots of capacitors and if you are doing electronic testing you should invest in an ESRWhat do you think guys? I only have a standard Multimeter and I normally check caps with them even thoe it takes a little longI cannot affordosciliscopes and esr testersThankseveryone I love this forum and the people your all fantastic people

author: EEVblog
author_rank: Unknown
timestamp: March 05, 2010, 10:16:20 pm
content: It's really only of great value for service techs, so they can find faulty electros in-circuit. If you don't service gear daily then it's not really an essential bit of lab kit.Dave.

author: VladKEasternTiger
author_rank: Regular Contributor
timestamp: March 06, 2010, 12:17:40 am
content: Thanks Dave, yes that makes sence as im new in the game

author: tuta
author_rank: Newbie
timestamp: May 18, 2010, 05:39:14 pm
content: HiAn ESR meter would make a great addition to my workbench too and so I started asking my friend google about esr meters. I found an interesting page from a guy in South America:http://www.ludens.cl/Electron/esr/esr.htmlIt seems to me that one could build a reliable meter with cheap parts. So if you don't want to spend lots of money I'd say this build would provide you with a good ESR-meter.However I've got hooked on electronics so badly that I am looking for professional ESR meter and don't mind to spend some money. I intend to keep at it (electronics) for a long time and so I think scopes and multimeters and all these devices are good investments.I also stumbled upon some LCR meters from Agilent:http://cp.literature.agilent.com/litweb/pdf/5990-3458EN.pdfAmongst various other functions they have a C measurement as well as a Series/Parallel mode. Maybe somebody can help me out here: Could I measure ESR by setting the thing to C in series mode?CheersTuta

author: Anders
author_rank: Contributor
timestamp: May 24, 2010, 09:52:54 am
content: Hi tuta,I had a look at the one you linked a while back but decided that this one seemed better at least for my purposes:http://members.shaw.ca/swstuff/esrmeter.htmlLow part count and no transformer made me decide this is a future project.

author: tuta
author_rank: Newbie
timestamp: May 25, 2010, 10:14:04 am
content: Hi AndersYou are right, I like yours better too. It seems to me it can be built in a shorter time than the other one.
Should I keep the silicone cover on my thermostatic switch or remove it? - Page 1
Forum section: electronics / beginners

author: Sourav
author_rank: Newbie
timestamp: November 11, 2024, 01:12:48 pm
content: Hello everyone! I’m working on a project that uses a thermostatic switch - KSD9700 250V 5A 70° C. It has a silicone cover as the attached image.From what I understand, the cover might protect against dust and moisture and provide insulation in case the thermostat body shorts (which won't be a problem in my case as the project is low voltage one). But I’m wondering if it affects the thermal response or accuracy of the switch. Does anyone have experience with this? Does keeping the cover on help with longevity and insulation, or would it be better off without it?

author: Poroit
author_rank: Frequent Contributor
timestamp: November 12, 2024, 06:56:29 am
content: G'day Sourav,The attached manual is written in Chinglish"Switch Material：Metal or PlasticThe metals outer shell type the product outer shell take an electricity, should add toinsulate a coat."I think they are saying that the metal case ones are alive so you will need to use the Silicon Insulator.

author: Sourav
author_rank: Newbie
timestamp: November 12, 2024, 08:30:12 am
content: Good morning, Poroit! Thanks for the insight!I’ve looked into it, and it turns out you were right about the potential for a short to the body. I tested it myself, and here’s what I found with my NC thermostat, which opens at temperatures above 70°C:1. When the thermostat is closed (below 70°C): There was no continuity between the metal body and the wires, as measured with my Kaiweets DMM in both continuity and resistance modes. My Mastech LCR meter showed a reading of 1.10 Megaohms in Rs (series resistance) mode at 1kHz and 12 Megaohms at 100Hz. In Rp mode, it showed 0, likely due to capacitance, which measured 8.3pF at 1kHz.2. When the thermostat is Open: When I heated the thermostat with a blower gun, it opened at over 70°C, and the metal body then became directly shorted with about 1.9 ohms resistance.3. Under the NC condition (below 70°C), I also tested it with an insulation tester set to 500V, and it showed 0.2 Megaohms at 357V.So, based on these results, it seems essential to keep the insulation on. As point 2 shows, there’s about 2 ohms resistance to the body when it opens, so leaving it uninsulated could definitely pose a risk!

author: Nominal Animal
author_rank: Super Contributor
timestamp: November 12, 2024, 09:02:06 am
content: The kinds of silicones used also have pretty good thermal properties. Consider sil-pads, for example: thermally conductive silicon insulators.
Should I make a kickstarter? - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: December 02, 2017, 02:06:57 pm
content: I introduce you to the lighter putter outer 100

author: Vtile
author_rank: Super Contributor
timestamp: December 02, 2017, 03:34:27 pm
content: I think you have a valid kickstarter stuff here.

author: Kalvin
author_rank: Super Contributor
timestamp: December 02, 2017, 03:46:35 pm
content: Too bad you didn't make to Slush ended yesterday.
Should I tear this apart to see what in going on? - Page 1
Forum section: electronics / beginners

author: larrybl
author_rank: Regular Contributor
timestamp: November 18, 2020, 12:59:15 am
content: Weird LED Bulb failure.https://www.youtube.com/watch?v=endUqO1Jyh8&feature=youtu.be

author: themadhippy
author_rank: Super Contributor
timestamp: November 18, 2020, 01:21:33 am
content: my money is one the discharge resistor across the capacitor dropper has failed

author: wraper
author_rank: Unknown
timestamp: November 18, 2020, 01:23:22 am
content: Not failure and not that weird. Some bulbs experience this while smoothing capacitor after rectifier is discharging.EDIT: If you run it without a long cable, it probably will stop doing this.

author: wraper
author_rank: Unknown
timestamp: November 18, 2020, 01:25:03 am
content: Quote from: themadhippy on November 18, 2020, 01:21:33 amThere is no capacitor dropper, it's not the cheapest shit from China without any real LED driver where this effect is actually impossible.

author: larrybl
author_rank: Regular Contributor
timestamp: November 18, 2020, 01:58:12 am
content: This was in a kitchen light, It came on at 1/2 brightness as the other light. Told my wife to turn it off so I could replace it. It stayed lit after being turned off. I replace it in the kitchen, and brought the bulb to the shop to see if I could document the failure.

author: larrybl
author_rank: Regular Contributor
timestamp: November 18, 2020, 01:59:40 am
content: so, is a tear down warranted? Or should I just toss it?

author: wraper
author_rank: Unknown
timestamp: November 18, 2020, 02:09:40 am
content: Quote from: larrybl on November 18, 2020, 01:59:40 amSo if it does not work properly when powered, it's just a faulty bulb. You can tear it down but there is nothing fancy inside. This might be simply one of the LEDs dying.

author: HwAoRrDk
author_rank: Super Contributor
timestamp: November 18, 2020, 03:05:01 am
content: Quote from: larrybl on November 18, 2020, 01:58:12 amHuh, what a coincidence, an LED bulb in my bathroom failed the exact same way the other day. Although, wasn't actually half brightness, but flickering very fast. Came on fully for about 2 seconds when switched off.
Should i try the 20QFN   Si4711 Si4703 - Page 1
Forum section: electronics / beginners

author: guitchess
author_rank: Regular Contributor
timestamp: May 03, 2022, 05:26:13 pm
content: Hello,Found some parts I would like to work with(Si4711 & Si4703). However, they are in 20QFN package. I work with SMT all the time, but usually stick with the larger parts. I don't have trouble with sot23 and sot23-6 parts. I make my own boards, and plan to make a test board.Considering they won't have solder mask, am i biting off more than i can chew? I don't want to waste money on parts I can't use.Anyone have any experience with these parts and have warnings/tips to share?

author: Terry Bites
author_rank: Super Contributor
timestamp: May 04, 2022, 01:12:17 pm
content: This is the method I've used before. Presolder the pads and then run your iron in a puddle of flux.

author: JPortici
author_rank: Super Contributor
timestamp: May 05, 2022, 03:52:44 pm
content: beware, those use the Retarded™ QFN with additional pads under the corners. They are a major pain to solder by hand.I suggest you tweak the pattern and make a 45 degree pad that come out of the corners, then you can put more solder and hope for a good connection
Should one supplement reading LAoE with AoE? - Page 1
Forum section: electronics / beginners

author: Quacko
author_rank: Newbie
timestamp: December 17, 2021, 05:03:54 pm
content: I've heard that supplementing Learning the Art of Electronics with readings from the Art of Electronics can be a good idea, but I've also heard that LAoE is essentially an independent book. How much would one benefit from supplementing LAoE with AoE readings?Thanks!

author: rstofer
author_rank: Super Contributor
timestamp: December 18, 2021, 03:59:10 am
content: "Learning the Art of Electronics" is supposed to be a lab manual to accompany the text book "The Art of Electronics". There is a third book "The X Chapters" which has upgraded lab experiments and other corrections. This became necessary because many of the lab experiments were dated and there were better devices and techniques..

author: uliano
author_rank: Regular Contributor
timestamp: December 18, 2021, 06:28:24 pm
content: Quote from: rstofer on December 18, 2021, 03:59:10 amIn the preface of LAoE I read<<If any reader i acquainted with the Student Manual. . . , published in 1989 to accompany the second edition of The Art of Electronics it may be worth noting principal differences between this book and that one. First, this book means to be self-sufficient, whereas the earlier book was meant to be read alongside the larger work. Second[...]>>In the text there are link to relevant chapter in AoE <<That book, now in its third edition and which we will refer to as "AoE," remains the reference work on which we rely. We no longer require that students buy it as they take our course. >> but each "day" (or subtopic) has "main & supplementary notes" providing the required theory needed and somewhat in-depth selected topics, "lab exercises" guiding into experiments, and "worked examples"QuoteThis has nothing to do with LAoE, instead it is a repository of all the advanced material they couldn't fit into AoE. It has five chapters numbered along the AoE TOC: 1 passive, 2 bjt, 3 fet, 4 op-amp, 9 power.

author: rstofer
author_rank: Super Contributor
timestamp: December 20, 2021, 11:46:33 pm
content: Here's one version of the Student Manualhttp://www.apple1.fr/student_manual_for_the_art_of_electronics.pdf
Should soldermask be removed from around hard gold edge connectors? - Page 1
Forum section: electronics / beginners

author: matthuszagh
author_rank: Frequent Contributor
timestamp: January 10, 2023, 08:38:50 pm
content: I'm designing a board with hard gold fingers and wondering about the proper way to handle soldermask. Of course, soldermask should be removed from the pads themselves, but should it also be removed from between the pads? I've attached two images, the first showing soldermask present around the pads and the second with soldermask removed from between the pads.Many PCBs I've seen with hard gold edge connectors opt for the second choice (soldermask removed), but I think I've seen others with it there. Which should I go with? I can't think of any reason why soldermask would be useful here - the pads aren't soldered to. And I fear the soldermask might wear from frequent insertions/removals, or something like that.Does it matter? Is this a fab house specific thing?

author: DavidAlfa
author_rank: Super Contributor
timestamp: January 10, 2023, 08:53:28 pm
content: Normally there's no soldermask at all, you'll see that in computer parts.I guess it could peel off and cause connection issues.

author: wraper
author_rank: Unknown
timestamp: January 10, 2023, 08:54:17 pm
content: I don't recall any commercially made boards with solder mask left. There is no advantage of having it. And I would not use it due to risk of contaminating contacts on both PCB and connector by scratched off solder mask after some insertion cycles.
Should Voltage Regulator pins be shorted? - Page 1
Forum section: electronics / beginners

author: Aerobyrd93
author_rank: Contributor
timestamp: September 02, 2015, 09:13:21 pm
content: So I have one of thesehttp://www.ebay.com/itm/261295849489?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITUnfortunately, it did not fit inside the enclosure I needed it to fit in, so I ended up removing most of the parts and resoldering them. Unfortunately, it was not as easy as I'd imagined, and perhaps mistakes were made. The unit is not currently functioning, outputting 0v, and I'm trying to diagnose the problem. My question is, should the two outside leads of the voltage regulator be shorted on the pcb? right now, I have it unattached, and all solder removed, and read a short. There is a picture on that page of the leads, in which it is the IC on the right side against the heat sink.Thanks for any help.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: September 02, 2015, 10:55:02 pm
content: If you're referring to the outside 2 pins on the 3-pin package in the middle of the board on the right side of this picture:It certainly looks like they're connected to me.

author: free_electron
author_rank: Super Contributor
timestamp: September 02, 2015, 11:00:36 pm
content: could be a big fat double-diode ... not everything in to220 is a regulator

author: LukeW
author_rank: Frequent Contributor
timestamp: September 03, 2015, 12:51:27 am
content: Almost certainly a big schottky double-diode.That wiggly meandered trace on the bottom foreground looks interesting in a DC application... I wonder what it's for. Current sense maybe?

author: sleemanj
author_rank: Super Contributor
timestamp: September 03, 2015, 01:37:39 am
content: Quote from: LukeW on September 03, 2015, 12:51:27 amYes, that will just be a current sense for an input to the CC circuit op-amp. Have seen this done also on constant current add-on modules for the cheap LM2596/2577 DC-DC modules.

author: Aerobyrd93
author_rank: Contributor
timestamp: September 03, 2015, 05:11:31 am
content: Thanks a bunch for the responses. It's embarassing to admit, but I did not check the part number of what I was thinking was the voltage divider, and now have it installed in a place which will be virtually impossible to remove. I have contacted the seller to ask for any info or schematics they can give me, and will post their response when it comes. As for trying to diagnose the so8, is it very likely that it would have been damaged by soldering components? I did probe around it a bit with a scope and got several different dc voltages, but couldn't tell you what it should be giving. It has no label on it to find a datasheet. Any tips of what I should be seeing at various points of this device would be helpful for the ongoing diagnosis. Meanwhile, I'll keep plugging away, I really need this one to work.Thanks again

author: G7PSK
author_rank: Super Contributor
timestamp: September 04, 2015, 03:08:59 pm
content: One heat sink has a MOSFET on it the other a double Schottky diode. On the one I have in my hand it is a P75NF75 and a Y20100 respectively.
Should you measure a battery using "a multimeter set to the 10 ampere scale"? - Page 1
Forum section: electronics / beginners

author: cdonges
author_rank: Newbie
timestamp: April 21, 2015, 06:44:58 am
content: http://www.abc.net.au/science/articles/2015/04/21/4220746.htmQuoteI would have thought you should measure charge by voltage?

author: BradC
author_rank: Super Contributor
timestamp: April 21, 2015, 07:33:15 am
content: Quote from: cdonges on April 21, 2015, 06:44:58 amGotta love Dr Karl.

author: mikerj
author_rank: Super Contributor
timestamp: April 21, 2015, 10:26:14 am
content: With a single cell using the 10 amps current range gives you a good indication of the cells internal resistance, which increases considerably for alkaline and zinc chloride batteries as they become depleted. Measuring the off-load voltage doesn't tell you much until the battery is virtually dead.I've checked AAA and AA primary cells using this method for years, though I would be wary of using this on the larger cells (e.g. D) which can source out a lot of current when new.

author: richard.cs
author_rank: Super Contributor
timestamp: April 21, 2015, 12:38:53 pm
content: For AA alkalines and similar it's a better method than terminal voltage because you get an idea of the internal resistance, but don't do it on any battery that can source lots of current. It'd be an exceedingly bad idea on a car battery, and probably a bit marginal on D cells (though not as much as you'd think, D cells haven't had the development AAs have so their internal resistances are comparable just with higher capacity).A new Duracell Procell AA at room temperature manages about 7A short circuit.

author: Matje
author_rank: Regular Contributor
timestamp: April 21, 2015, 10:25:08 pm
content: Quote from: cdonges on April 21, 2015, 06:44:58 amYou do.Obviously while drawing a defined current from the battery, the current depending on battery type/size.At least that is what all halfway serious battery checkers do. As has been pointed out already, just measuring the short circuit current of a battery is a bad idea, it may damage the battery or the measurement equipment. For demonstration purposes put a big wrench or similar across the terminals of a fully charged car lead battery and watch what happens. On second thought: don't, it's dangerous, these things put out hundreds of amperes.

author: mikerj
author_rank: Super Contributor
timestamp: April 21, 2015, 10:44:28 pm
content: Quote from: Matje on April 21, 2015, 10:25:08 pmAn AA alkaline cell and a 12v car lead acid battery are hardly comparable in terms of discharge current.

author: Shirley Marquez
author_rank: Newbie
timestamp: April 22, 2015, 02:33:08 am
content: Don't try it with an NiCd or NiMh battery. They can source a lot more current than an alkaline AA can.
Shout out to another youtube video blogger - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: July 22, 2015, 07:47:32 pm
content: I just stumbled across another excellent youtube video blogger (actually, youtube "recommended" it) named Scullcom Hobby Electronics. He's a Brit (sorry, don't know his name but he kind of resembles Michael Caine, the actor). If your a beginner like me, I can highly recommend his videos. I've only watched his constant current source video and his latest videos on building a function generator but the content and delivery I found to be excellent. I'm only plugging this because I enjoyed his videos so much. And no, I have no association with his channel. Check it out.Ps. He draws the neatest whiteboard schematics I've ever seen.*corrected name of channel

author: retiredcaps
author_rank: Super Contributor
timestamp: July 22, 2015, 08:16:36 pm
content: Quote from: steverino on July 22, 2015, 07:47:32 pmCorrecting, only so when people do a search, they land at the right place.It is Scullcom, not Skullcom. His channel is athttps://www.youtube.com/channel/UCDqryeq1kMDSEQwltWqASrA/videoswhich I mentioned before.https://www.eevblog.com/forum/testgear/scullcom-youtube-channel-reviewteardown-of-older-dmm/

author: Unknown
author_rank: Unknown
timestamp: July 22, 2015, 11:10:24 pm
content: Thanks for the correction. I revised my original post to reflect the correct name.
Show Ascii for I2C on Keysight DSOX1204G - Page 1
Forum section: electronics / beginners

author: manuel42
author_rank: Contributor
timestamp: April 15, 2021, 11:51:23 am
content: I try to check the I2C output on a Keysight DSOX1204G OscilloscopeIt shows the data and it even lists it in a table.Does this Oscilloscope support showing ascii instead of hex?If so, how can this be configured?

author: ElizatronicWarfare
author_rank: Contributor
timestamp: April 15, 2021, 12:21:01 pm
content: X-series keysight scopes absolutely can decode digital data into ASCII, it's an advertised feature on all the datasheets. The bus must be configured for at least seven bits, then go to Serial > Settings > Base > ASCII. The exact menu path for the dinky little 1000G's might be slightly different to what I know, but it should be there unless the function was removed in the economy models (unlikely).

author: manuel42
author_rank: Contributor
timestamp: April 15, 2021, 01:28:36 pm
content: This is what i've thought, but i can't find this setting.I've attached screenshots of the configuration, but can't find the settings menu.

author: manuel42
author_rank: Contributor
timestamp: April 15, 2021, 02:03:57 pm
content: My bad i guess.It seems it just depends on the protocol and when i check serial (UART), i get the the selection for hex, binary and ascii.I think ascii just doesn't make sense for I2C
Show output from a vU meter on a 10 Segment Led Bargraph - Page 1
Forum section: electronics / beginners

author: grant1842
author_rank: Newbie
timestamp: May 30, 2019, 12:31:53 am
content: I am using this simple 555 timer circuit to measure ESR. Please see schematic attachments.It does a great job and shows great on the small vU meter.I would like to use a 10 Segment Led Bargraphhttps://tinyurl.com/y44sduddto show the measurement.I would like to use and Arduino to look at the current/voltage and drive the Leds with it based on the current/voltage measurements.I know there is small current at the Meter. I all son know i will need to drive the LEDS with 3v> <5.I am not sure about an op amp or something to boost the signal or a different solution.Thanks for your help and guidance.

author: MarkF
author_rank: Super Contributor
timestamp: May 30, 2019, 12:49:46 am
content: Here, I will let you pick your flavor.Couldn't be bothered to check the input voltage levels required.

author: Brumby
author_rank: Unknown
timestamp: May 30, 2019, 01:36:21 am
content: What MarkF said.

author: grant1842
author_rank: Newbie
timestamp: May 30, 2019, 01:57:43 am
content: Thanks for the info. I will look at those chips
Shunt Resistor with a LM339 - Page 1
Forum section: electronics / beginners

author: eev_carl
author_rank: Regular Contributor
timestamp: August 22, 2018, 01:57:30 pm
content: Hi,I made a simple series resistive circuit to test out a shunt resistor. The circuit is shown in the schematic below. 1V DC is sent through a pair of resistors: 0.7ohm and 10kOhm. The 0.7ohm is a value I measured directly on my MM of 3 "1.5ohm" resistors in parallel.I'm using an LM339 to amplify the difference between the 1V supply and the junction of the 0.7 and 10k resistors. I got a current value of 2.23mA which is much higher than the value I measured directly with my MM (187uA). These are my calculationsA = 1 + 10/1 = 11Vdiff = 17.6mV / 11 = 1.6mVI = 1.6*10-3 / 0.7 = 2.23mA17.6mV is the value I measured on the output of the LM339. The supply to the LM339 is 9V. I don't have any other 3 op amp son the LM339 connected.Feel free to suggest another measuring technique if I'm off base with the comparator.Thanks,Carl

author: glarsson
author_rank: Frequent Contributor
timestamp: August 22, 2018, 02:12:50 pm
content: LM339 is a comparator, not an op-amp. The feedback from the output should go to the negative input to create a differential amplifier (and replacing the LM339 as well). The top connection of the sense resistor has the higher voltage and the bottom connection has the lower voltage. You wired it the other way.

author: eev_carl
author_rank: Regular Contributor
timestamp: August 22, 2018, 02:45:42 pm
content: Should I run the comparator without feedback into an amplifier? Is the comparator of any use or should I just use an op amp.Thanks

author: glarsson
author_rank: Frequent Contributor
timestamp: August 22, 2018, 03:00:53 pm
content: First, the 339 has an open collector output. This means that it can't output a voltage, only pull down a voltage provided by a pull up resistor or similar. The 339 flips the output based on which input has the higher voltage. It doesn't act as an amplifier. If you want to amplify the voltage over the sense resistor you need an op amp. Also, the op amp must be able to handle signals close to the power supply. In your application the signals are within 1V of the negative power supply of the op amp, ground in this case. Not all op amps can do this.

author: eev_carl
author_rank: Regular Contributor
timestamp: August 22, 2018, 03:52:46 pm
content: Thanks. LM339 is the wrong IC for what I'm trying to do

author: David Hess
author_rank: Super Contributor
timestamp: August 22, 2018, 04:46:56 pm
content: It is possible to externally compensate the LM339 comparator to operate as an operational amplifier but the circuit as shown would not work anyway.
Shutdown enable circuit for LM3478? - Page 1
Forum section: electronics / beginners

author: makebit
author_rank: Unknown
timestamp: October 06, 2025, 11:40:59 am
content: Hi,On page 15 of the LM3478 datasheet it offers a shutdown/enable circuit for theLM3478.Do you think our circuit attached will suffice to shutdown/enable it?LM3478https://www.ti.com/lit/ds/symlink/lm3478.pdf?ts=1759672423581

author: mikerj
author_rank: Super Contributor
timestamp: October 06, 2025, 09:23:48 pm
content: Seems you have forgotten to attach anything.

author: temperance
author_rank: Super Contributor
timestamp: October 06, 2025, 10:46:16 pm
content: There are only a few requirements:Thou shalt not supply this pin with more than 7 V.Thou shalt lift the SD/FA pin higher than 1.35 V to shut down the device.Thou shalt not load the pin down with the shut down circuit, such that the Frequency set forth by the Resistor is rendered wrang.The verra weel kent hook up curcuit is depicted in Figure 26 o’ the dookment.https://www.ti.com/lit/ds/symlink/lm3478.pdf?ts=1759672423581Just an open drain circuit pulling the pin low to switch the machine.But thou shalt describe us the couplings, that its graith might be understood by all who look upon it.
Si4732 + BK1080 on same communication lines? Is this real or a joke? - Page 1
Forum section: electronics / beginners

author: u666sa
author_rank: Frequent Contributor
timestamp: November 09, 2024, 09:28:47 pm
content: You are looking at photo of Quansheng UV-k5 board with Si4732 dauther board modification of unknown (yet unknown) version. On top, you have the stock BK1080 fm chip. Question is this. Could this be a joke photo someone made for funs? Or, perhaps this is a possibility? Two chips at the same time?Usually we remove Bk1080 and install daugher board in its place...There is only one firmware that lets you select between different radio, r3b0rn by fagci, but it's either one or the other. Mod where you keep two chips is unknown. Something tells me this is a joke.как залить файл на файлообменник

author: ftg
author_rank: Frequent Contributor
timestamp: November 11, 2024, 09:12:33 am
content: Not considering the RF side, the communications line is just I2C.As long as the BK1080 and Si4732 don't have the same address, it should be fine.
Side Question -- Why do button lights flicker on when power goes off? - Page 1
Forum section: electronics / beginners

author: outsidequery
author_rank: Newbie
timestamp: January 12, 2021, 02:47:28 am
content: I have a LED lamp with some lighting buttons that glow when pressed (that control the actual light). I noticed that if I have this plugged in to a power bar and turn off the power to the plugin, the buttons glow for a second (supposing they were previously dark.) (This is the case for Furman PST-8D and for an old Tripp-Lite surge protector.)What might this mean? Is it likely something the lamp does simply when the power goes off, or does something else happen at the powerbar outlets when I switch off the power bars? Not that I can get any definitive answer here.The LED looks vaguely like thishttps://www.amazon.com/TaoTronics-Charging-Lighting-Brightness-Licensing/dp/B00APAQSP6/ref=sr_1_21?dchild=1&keywords=led+lamp&qid=1610419107&sr=8-21but it is not the same model; perhaps it is an older version. The light-buttons are on the base.

author: helius
author_rank: Super Contributor
timestamp: January 12, 2021, 03:23:59 am
content: This is an effect of sloppy power sequencing. The power to light the LEDs comes from capacitors that hold a charge for a while after power is removed. The actual LEDs themselves would be turned on and off using a transistor as a switch, with the base (or gate) controlled by a MCU. When power is removed, the MCU should go into shutdown mode and turn off its outputs. If it doesn't do this in the correct way, the transistors can be left in the ON state instead of the OFF state as desired.

author: Brumby
author_rank: Unknown
timestamp: January 12, 2021, 04:22:23 am
content: There doesn't have to be an MCU involved. Ordinary logic gates or even linear circuits can result in the same thing... capacitors hold power which can illuminate the lights and the signals controlling the lights drop into "indefinite" states. Depending on the specific nature of these states, the lights can be switched on for a moment.Normally, such behaviour is completely ignored as it does not represent a valid condition of such circuitry (You know ... it's just been turned off!)There is the situation where such light flickering (of lights or whatever) IS an issue. In those cases, special design considerations are made to ensure the circuit behaves as required in all circumstances.In a number of situations, power sequencing - both powering up and powering down - is vitally important. Some lab supplies have such functionality.