hybridfree/eevblog-posts huggingface dataset:
Multimeter for electronics - Page 1
Forum section: electronics / testgear

author: hellzakk
author_rank: Contributor
timestamp: April 27, 2016, 09:36:50 am
content: Hi all, i've searched the forum but i dont have found the answer so im here to ask what multimeter would you suggest to a newbie for arduino-like developmentFollow your review and opinion im following the bm867s... im going in the right direction?

author: Fungus
author_rank: Super Contributor
timestamp: April 27, 2016, 09:49:52 am
content: Quote from: hellzakk on April 27, 2016, 09:36:50 amThat's what they all say...Quote from: hellzakk on April 27, 2016, 09:36:50 amBrymen is a good choice.You can get a blue one with EEVBLOG logo (in the store - if there's any left)

author: hellzakk
author_rank: Contributor
timestamp: April 27, 2016, 09:56:18 am
content: yes, i dont really need a industrial multimeter with super-specific options like many of the high-end multimeter... ad like to know from you expert a good multimeter with the options needed for what i can need in the future

author: Fungus
author_rank: Super Contributor
timestamp: April 27, 2016, 10:43:59 am
content: Quote from: hellzakk on April 27, 2016, 09:56:18 amI'm not sure it's possible to ever buy a future-proof thing.A good bit of advice is to get two meters. One expensive one (eg. a Brymen) and one cheap one. Whenever you get a weird reading you can use the other meter to verify it. If both meters agree then you can be fairly sure it isn't the meter.Also: Sometimes you just need two meters - to look at two different values simultaneously (eg. volts and amps)The "cheap one" can be one of those $5 multimeters you see around the place. They're disposable if you break them and they measure quite well. Just use them for volts/ohms/low currents and don't connect them to mains power.A fun project is to build a box with reference values for resistance/voltage/etc. to confidence-test your meters every now and again.Measurements are all aboutconfidenceand that's difficult to achieve with a single meter no matter how much you paid for it. Getting a second opinion when things don't make sense isalwaysgood, even if it's from a $5 meter.

author: hellzakk
author_rank: Contributor
timestamp: April 27, 2016, 11:19:10 am
content: Quote from: Fungus on April 27, 2016, 10:43:59 amaha sure, i mean future-proof for my abilitybut it's clear, i've just ordered the brymen bm867s
Keithley/Tektronix DMM 7510 & SMU 2450|2460 Display Delamination Issue - Page 1
Forum section: electronics / testgear

author: matthewpang
author_rank: Contributor
timestamp: April 26, 2016, 03:18:34 am
content: Hey All,I've noticed some display delaminationissues with our Keithley instruments and wanted to see if anybody else is experiencing a similar problem. We've had this issue with several Keithley instruments now and we have sent a SMU 2450 back under warranty as it was *really* bad (very large bubbles in the screen).See attached pictures / videos - it is difficult to capture on camera but in the photos but you can see it as the region of discoloration/distortion in the display and in the videos you can see the discoloration/distortion change as I press down on it (indicating that the a layer of the display has separated from the layer under it). This is much more obvious in person when using the instrument.As I mentioned, our previous SMU 2450 worsened to the point of extremely large and noticeable air bubbles (almost like an *extremely* badly applied screen protector - except *in* the display ) and it was returned to Keithley under warranty (alas at that point I didn't think to take pictures of the problem). We received the replacement SMU 2450 back today and I noticed a similar (but less major) issue on the new unit's screen and checked our DMM 7510 and noticed the same.Are you folks seeing similar issues in your units? ( I would also be interested to know if other Keithley instruments that share the same platform face the same issue)SMU 2450 ImageDMM 7510 ImageSMU2450 Videohttps://www.dropbox.com/s/89xaiwgqsb6p6kk/IMG_5699.MOV?dl=0DMM 7510 Videohttps://www.dropbox.com/s/g1qu6jk7va7d6cn/IMG_5696.MOV?dl=0Cheers,Matt

author: HighVoltage
author_rank: Super Contributor
timestamp: April 26, 2016, 03:00:00 pm
content: My 2450 shows the same when turned off but I do not see it, when it is turned on.I think it has to do with the touch screen, probably two screens are very close to each other.It does not bother me and I don't think it is defect.

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 26, 2016, 03:36:53 pm
content: These displays often consist of several foils, like Polarisator, color filter, reflex filters, and so on.These are glued tightly together, in most cases, so that neither air nor humidity can cause such color fringes (optical interference between thin layers) .. That's no delamination, and no real defect, I think.If the additional touch pad foil (resistive or capacitive) is separately attached to the display, (due to yield and production reasons), it is not glued to the display.Maybe in this case it's sitting on a separate plastic protection cover, and there's an air gap between display and cover.Or the touch foil is simply stretched over the displays front cover..That may not disturb you, when the display is lit and viewed from a perpendicular angle.Anyhow, this is not the highest quality of realization for a touch display, it's more a cheap solution, and no great expertise at Keithley how to do this correctly.Frank
Siglent SDG1025 doesn't remember last setting as you would think it should - Page 1
Forum section: electronics / testgear

author: v8dave
author_rank: Regular Contributor
timestamp: April 25, 2016, 12:33:30 am
content: It would seem that the PowerOn last setting does not just load the last used setting it only loads the one you currently have if you go into the utility menu and change this from default to last before you switch off the device. Now if you power up, it uses these settings. I was expecting it to use this setting to simply load the last used settings. It took me a bit of time to figure out what was happening with this setting.

author: tautech
author_rank: Super Contributor
timestamp: April 25, 2016, 01:10:48 am
content: IIRC this was fixed in FW some time ago and "power on = Last" certainly works with FW 37R3.Just checked.http://siglentamerica.com/download/software/SDG1000-V100R001B01D01P37R3.rar

author: v8dave
author_rank: Regular Contributor
timestamp: April 25, 2016, 01:15:35 am
content: Quote from: tautech on April 25, 2016, 01:10:48 amI am running that version. If I power up, change the frequency and then power off and back on, it powers up at the frequency it was previously powered up to not the changed one. The only way to get it to remember this is to go into the utility setting and change to LAST and then select DONE before I power off.

author: tautech
author_rank: Super Contributor
timestamp: April 25, 2016, 01:42:34 am
content: Quote from: v8dave on April 25, 2016, 01:15:35 amCorrect.If you wish for these AWG's to power on using the last used setting, what you describe is the appropriate configuration. After which any power on should return last used settings, it does on mine.QuoteHowever I can't replicate this ^^^and suggest you return the AWG to a default state and then apply the power on = last setting. Sorry, I don't know what else to suggest.Be aware until you get used to these units the UI can be a little confusing as one must toggle between channel screens for setups and the left BNC is for Ch1 while the GUI (yellow) is on the right of the display. Counterintuitive IMO. Wonder why Siglent haven't fixed that.

author: v8dave
author_rank: Regular Contributor
timestamp: April 25, 2016, 01:50:06 am
content: Quote from: tautech on April 25, 2016, 01:42:34 amNow that I am aware that this is the way it should work I can live with it.The UI is a little confusing at first and I have hit the wrong button a few times but as I only bought this a couple of days ago I am still playing around with it. For the price I can't complain too much and it has allowed 2 existing projects to be almost completed in double quick time so money well spent.

author: tautech
author_rank: Super Contributor
timestamp: April 25, 2016, 02:02:38 am
content: Great, glad to hear it's been useful for you.Anymore problems just yell.
Brüel & Kjær Band Pass Filter Type 1617 - Page 1
Forum section: electronics / testgear

author: downwind27
author_rank: Newbie
timestamp: April 25, 2016, 04:28:38 pm
content: Found this lovely unit recently, looks like it is a switchable band pass filter covering the audio range. Anyone any idea what it would have been used for? It looks like it can be controlled remotely and will drive some sort of recorder. Maybe for testing amplifiers in R&D or production?

author: woodchips
author_rank: Frequent Contributor
timestamp: April 25, 2016, 05:29:58 pm
content: Yes, wonderful, unfortunately like all B&K stuff it is pretty useless.No manuals.Signal connections unlike anything you have ever found anywhere else.Miserable design so you can't even get inside to tap onto the signals and use a different connector.After buying a pile of audio B&K equipment most ended up on the scrap pile, simply not worth the effort of trying to use or fix. Possibly someone at B&K might read this and put the manuals on line, but I doubt it, they seem to be the sort of company to hold everything to themselves.You can guess I am not impressed!
New Pico 2000 Series Scopes - Page 1
Forum section: electronics / testgear

author: rickv14623
author_rank: Frequent Contributor
timestamp: April 25, 2016, 07:25:31 pm
content: Launch day today. Opinions?

author: Gyro
author_rank: Super Contributor
timestamp: April 25, 2016, 09:09:10 pm
content: I briefly got excited when I got their Test and Measurement news this morning, but they look a pricey option for the decent spec ones.

author: rstofer
author_rank: Super Contributor
timestamp: April 25, 2016, 09:37:30 pm
content: It seems to me that the 2205A (2 analog, 16 digital, waveform generator) doesn't overwhelm the Digilent Analog Discovery and it's a couple of hundred dollars more expensive. Right off the bat, the Analog Discovery has a 14 bit ADC versus 8 bit for the 2205A. Does it matter? Well, maybe when you have a display with a whole bunch of pixels.The 2205A has BNC connectors for the scope channels whereas the AD needs an extra adapter board to gain that funcionality. The 2205 certainly has better, albeit bigger, packaging.

author: pascal_sweden
author_rank: Super Contributor
timestamp: April 26, 2016, 05:14:26 pm
content: They do carry a warranty of 5 years though, which is worth noting!
HP 33120a square wave output versus Sync output at higher MHz frequencies? - Page 1
Forum section: electronics / testgear

author: Dekatron
author_rank: Newbie
timestamp: April 23, 2016, 09:12:30 am
content: Hi All,I am quite new to using the 33120a that I bought recently. I have checked this forum and other sources but can't find an answer to my question.I have hooked it up to two different scopes, one at a time, one being an old HP 1740A (still in very good order) and also to my Lecroy Waveace 2004. Both scopes show a quite nice (some ringing) signal on the sync-output up to 15 MHz, but the main output shows more of a sine wave signal on both scopes the higher the frequency gets.I have used an RG-58 cable with a T-connector at the scope end with a 50 Ohm terminator (also tested the 50 Ohm input on the 1740A but got same results, without the terminator then) when making these measurements.Am I making something wrong or what could be the cause for the square wave output looking like a sine wave when it gets above 5-7 MHz (approximately)?Best regards,Martin

author: tggzzz
author_rank: Super Contributor
timestamp: April 23, 2016, 09:25:31 am
content: Quote from: Dekatron on April 23, 2016, 09:12:30 amFirst understand how a square wave is composed from sine waves - the Fourier series.7MHz fundamental => 21MHz 3rd harmonic (no second harmonic, of course).33120 square rise/falltime <20ns. 20ns => bandwidth of 18MHz (rule of thumb BW=0.35/tr).21MHz > 18MHz, so the 20MHz will be attenuated.

author: jpb
author_rank: Super Contributor
timestamp: April 23, 2016, 09:26:59 am
content: The sync output is only concerned with timing rather than wave shape so probably has a faster rise time but more ringing and no control over amplitude and duty cycle.From the data sheet the rise time on the 33120a is < 20nsecs so up to 20 nsecs. If we assume the fall time is the same and we have a 50% duty cycle then at 10MHz with a period of 100 nsecs, a half wave must happen in 50 nsecs and 20 nsecs rise plus 20 nsecs fall will take up 80% of this so it will be looking very rounded at 10MHz.At 15MHz the half wave length (or half period) will be 33 nsecs so there won't be time for a complete rise and fall so don't be surprised it looks very sine like.

author: Dekatron
author_rank: Newbie
timestamp: April 24, 2016, 07:19:32 am
content: Thank you tggzzz and jpb, that explains it!I didn't think about the rise time.I also found the schematic and saw that the Sync output is a simple logic output but the main output has a proper driving stage.

author: tggzzz
author_rank: Super Contributor
timestamp: April 24, 2016, 08:25:41 am
content: Quote from: Dekatron on April 24, 2016, 07:19:32 amWith any data sheet or legal contract, always look at all the Ts&Cs or parameters, understand why they are there, in what circumstances they are relevant, and what they aren't saying.
Maynuo electronic load calibration procedure (9711) - Page 1
Forum section: electronics / testgear

author: kt315
author_rank: Regular Contributor
timestamp: October 25, 2015, 06:33:33 am
content: Hi,I recently got a clone of Maynuo M9711 150W load. And, call me dumb, but I cannot find any details on the calibration process.I believe I've seen some anecdotal evidence on the forum that there were folks who successfully calibrated M9712.If someone could share some links/references/light in general on the topic, that would be highly appreciated.Cheers.

author: DuPe
author_rank: Regular Contributor
timestamp: April 21, 2016, 07:13:22 pm
content: late, but maybe still welcome

author: DuPe
author_rank: Regular Contributor
timestamp: April 21, 2016, 07:19:27 pm
content: Whow,really still seems to be welcome: 5 Downloads in some seconds.Is it also the voltage that seems out of cal as with mine?
Owon ODP3032 Power Supply OVP Issue? - Page 1
Forum section: electronics / testgear

author: charlieb83
author_rank: Contributor
timestamp: April 18, 2016, 02:36:39 am
content: Hello all,I just received an Owon ODP3032 power supply and I think I'm seeing an issue with the over voltage protection as well as the constant current setting. I must admit that I'm completely new to programmable power supply so I'm not sure if these are actual issues or just a part of normal operations.What happens is that when I set the over voltage protection to a certain value, say 12.5 volts, the unit allows me to go over this voltage for several seconds before shutting the output off. I can set the output to something like 22 volts and when the output is turned on, the voltage goes up to 22 volts, stays there for about 2 seconds, then the unit trips on the over voltage protection.I would think the purpose of the over voltage protect would be to protect anything attached to the output and not allow to go above the set point at all.Another issue seems to be with the constant current setting. When I set the current output to a certain value, with a load on the output, I raise the voltage and the current value will increase past the current set point and the unit will not switch into constant current mode until the current is about 25 milliamps above the setting for the current.Any thoughts would be greatly appreciated.-CharlieHere's an example video showing both of these situations:https://youtu.be/Uq3iZc89DOs

author: sotos
author_rank: Frequent Contributor
timestamp: April 18, 2016, 04:44:57 am
content: Sent it back for a replacement.It’s not working correctly.

author: charlieb83
author_rank: Contributor
timestamp: April 19, 2016, 03:16:08 pm
content: Thanks Sotos, I thought something didn't seem quite right to me.

author: Zbig
author_rank: Frequent Contributor
timestamp: April 19, 2016, 04:11:11 pm
content: Also to me, from the overall behavior of OV and CC modes you've shown, apart from the obvious faults, it looks like these modes are purely firmware-based. Almost as if instead of a proper analog comparator action happening there (and merely reporting to firmware after it does its thing), there was just some crude slow software loop checking for limit breach conditions once in a blue moon. Needless to say, that's not what you want from a lab supply and if my musings are substantiated, I wouldn't trust that design.
HP 7044B X-Y Recorder Manual - Page 1
Forum section: electronics / testgear

author: barry14
author_rank: Regular Contributor
timestamp: April 22, 2016, 08:39:44 pm
content: I just acquired an HP 7044B X-Y Recorder on Ebay. A google search for a copy of the manual has yielded several sites but each one only has the first 18 pages of the manual. Does anyone know where to obtain the full manual? The Agilent site has no manual at all. Thanks.
EVB ESR Meter kit - full experience - Page 1
Forum section: electronics / testgear

author: pixel63
author_rank: Contributor
timestamp: April 19, 2016, 12:17:48 pm
content: I've just received my new ESR Meter Kit from EVB (Portugal), based on Bob Parker K7214 MKII original project.I'll post my entire experience on the unboxing, assembling, testing, calibrating and using it on my repairs.Bye.Pixel63

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: April 20, 2016, 02:25:57 am
content: I bought one of these kits many years ago. The design still looks to be the same today.It works perfectly well for my purposes, and it has had a lot of use BUT:The on/off switch is absolutely an appalling design. It doesn't work reliably or repeatably and drove me nuts. It consists of a TAC switch on the PCB with a length of silicone tube pushed over the tang. This has to be JUST the correct length to kiss the back of the membrane on the front panel. The practical movement of the membrane is less than the movement of the switch between 'not touching' and 'operated' so the switch has to be under some amount of 'pre-load'. Finally I removed the offensive item and mounted a small push button in the front panel, with a home-machined guard to stop accidental operation.In addition the case is VERY tight for space and doesn't latch closed reliably because of this. In fact some brands of 'PP3' 9V battery are fractionally too wide to allow the case to click shut.Regards, BT

author: pixel63
author_rank: Contributor
timestamp: April 20, 2016, 10:06:52 pm
content: ROUND 1Unboxed, plenty of components, ohhh.Here the images of the content of the kit and of the PCB from both sides.I've soldered the resistors, the diodes and the sockets for ICs and displays (last image).
Discover the Power of the Mixed Signal Oscilloscope (MSO)   --  1 hour webcast - Page 1
Forum section: electronics / testgear

author: ez24
author_rank: Super Contributor
timestamp: April 18, 2016, 05:57:45 pm
content: when:April 21, 201610 a.m. PT / 1 p.m. ET (US times)where:https://event.on24.com/eventRegistration/EventLobbyServlet?target=registration.jsp&eventid=1090841&sessionid=1&key=CEFA73DBD892EC34F498EF62365A13A6&partnerref=Keysight&sourcepage=registerQuestion: Does Keysight announce these on this forum - in other words - is this a duplicate announcement ? IF so sorry.
coverting analog to digital meters on old test equipment - Page 1
Forum section: electronics / testgear

author: trog1058
author_rank: Newbie
timestamp: April 18, 2016, 02:57:16 am
content: Does anyone have a good link or information for converting analog to digital meters.

author: tggzzz
author_rank: Super Contributor
timestamp: April 18, 2016, 07:00:23 am
content: Without knowing what you are considering or why you are considering it, that is tough to answer.You might like to consider what lead the OP of that thread to his conclusion:https://www.eevblog.com/forum/testgear/analog-meter-advantages/msg912932/#msg912932
Beckman Circuitmate DM45 DMM Manual or Specs? - Page 1
Forum section: electronics / testgear

author: isobig
author_rank: Contributor
timestamp: April 15, 2016, 01:43:37 am
content: Hello everyone! While digging through some storage boxes I found an old DMM that is a Beckman Circuitmate DM45. I got it in the late 1980's (I think) and of course the manual is long gone. It still works and it got me wondering if a manual is available somewhere for it as I would like to see the specs on it. I know it's not anywhere close to a top of the line meter but just curious about it. I did a google search but it didn't provide me with anything for this model. I also checked ebay just to see if anyone was selling this model and again nothing. Also searched here and didn't find any mention of this model.I would appreciate any help in finding the specs on this old beast.Thanks!

author: radhaz
author_rank: Regular Contributor
timestamp: April 16, 2016, 04:35:40 pm
content: http://www.americanradiohistory.com/Archive-Radio-Electronics/80s/1984/Radio_Electronics_Dec_1984.pdfAn ad claims .5% VDC accuracy, whatever that means.

author: isobig
author_rank: Contributor
timestamp: April 17, 2016, 08:53:04 pm
content: Wow... that took some digging it seems. I would assume (yes I know what that means) that the 0.5% vdc accuracy means it should be accurate to within 0.5% of the actual voltage when measuring DC. So if the actual voltage is 100vdc then the meter should display a value in the range of 99.5 - 100.5 volts. Again assuming the accuracy implies +/- of the actual voltage. If someone has more knowledge of this, please post with the details.
Anyone with experience on these UNI-T UT511/12/13 - Page 1
Forum section: electronics / testgear

author: 4cx10000
author_rank: Regular Contributor
timestamp: April 15, 2016, 05:58:02 pm
content: Hi!I'm about to buy an UNI-T UT511, 512 or 513, but haven't seen, or read, any review from technicians that have used them in daily work. By any chance, are there anyone out there that could tell me if it is just crap or an good insulator tester?

author: rsjsouza
author_rank: Super Contributor
timestamp: April 15, 2016, 08:50:33 pm
content: I have a UT513 and highly recommend it if you cannot find the UT513A for a reasonable price (more on this below).Its construction feels moderately solid (may not survive a 3m drop, though), the cable shrouds are pretty deep, the length is pretty convenient and the wires have a good quality feel to them. The display shows the relevant information in a very clear way, as well as the lighted buttons in the main panel.In my projects I usually exercise it at moderate ranges (1~5G) and could evaluate its accuracy up to 200M - it is spot on. Its output voltage is also pretty close to its ratings and it is one of the cheapest units to go up to 5kV/1T.The only significant drawback of the UT513 is that it will lock/reboot itself if there is a voltage breakdown on the DUT - the UT513A is improved.To recover is pretty easy: there is a "unlock" button that acts more like a "reboot". According to the manual, this button is designed for scenarios where the unit locks up but still leaves its output engaged. I like this especially because this unit does not have any "clunking/mechanical" switches that disengage the supply - all buttons are "soft buttons".The power supply feels something to be desired but I like the fact it is a real transformer and not a switching converter (better insulation in case anything goes wrong). One thing I dislike a bit is the use of C-batteries.IMHO you can't go wrong with this unit for hobby/lab purposes. If you are looking for robustness, shrouding it in a rubber sleeve may be mandatory.

author: 4cx10000
author_rank: Regular Contributor
timestamp: April 16, 2016, 12:08:04 pm
content: rsjsouzaThanks so much for taking your time to write and share your experience, indeed that was all I wanted to know. I had a look at the 513A and prices are slightly higher than 511 and 512, but that is not a concern. The most important is that I can rely, which you kindly told me about, on the tester and that it not cracks and goes into 1000 pieces in normal use. Of course it would be fine if it could stand a 3 meter drop.What caught my eyes when I first saw these testers was the display and truly, that gets even better when I read about its accuracy - spot on. I like the size of the instrument, it doesn't necessarily have to be like an normal-DMM-size.For sure there is times when more than 2,5kV is needed, so therefore I will go for, as you recommended, the 513A. I have a few projects running that might need higher voltages, but first out will be a insulation integrity test in our house.Thanks again rsjsouza for taking your time to write a detailed feedback including your experience with the UT513
Agilent I2C decode on MSO6 and 7k series scopes - Page 1
Forum section: electronics / testgear

author: wreeve
author_rank: Unknown
timestamp: April 16, 2016, 10:58:00 am
content: I’ve a MSO7054B which does sterling service usually…. however I can’t seem to get I2C decode working! Here is what I get on a valid I2C exchange. The decode doesn’t work! UART and SPI decode work fine. Must be something simple? All you have to do (I think!) is set up the SDA and SCL channels and the number of bits in the address (7).It is triggering on the “START” by the way so it notices the start condition as a trigger! This is a valid exchange btw; works fine.Any ideas?

author: nctnico
author_rank: Super Contributor
timestamp: April 16, 2016, 11:41:55 am
content: Did you set the threshold levels? Settings these is a bit tricky on this scope! You have to go into the signal setting menu and press the button for the signal. Doing that allows to set the threshold for the signal with the trigger level knob.

author: Howardlong
author_rank: Super Contributor
timestamp: April 16, 2016, 11:45:48 am
content: Following on from nctnico's advice, are you sure clock and data are the right way around? It looks like it may be continually seeing start states as the bus decode is switching mid-byte.Edit: I am sure nctnico is right, your SCL trigger level on channel 1 is at ground for example: you adjust the thresholds by adjusting thr trigger level when using analogue channels for I2C decode when selecting the channel for SCL, and then the same when you select the SDA channel.

author: wreeve
author_rank: Unknown
timestamp: April 16, 2016, 01:39:26 pm
content: Thanks guys; pushing the level button a few times finally got it to set at 50% and as if by magic decode worked. I was confused as the waveform appeared to be triggering OK but the level wasn't acceptable to the I2C decoder! Thanks again.

author: Howardlong
author_rank: Super Contributor
timestamp: April 16, 2016, 11:25:43 pm
content: Bob's your uncle!

author: Smokey
author_rank: Super Contributor
timestamp: April 16, 2016, 11:53:51 pm
content: Quote from: Howardlong on April 16, 2016, 11:25:43 pmNot true... Not true at all. Lets stick to the facts!
Current Limit for Diode Testing - DMM - Page 1
Forum section: electronics / testgear

author: ultrasmurf
author_rank: Regular Contributor
timestamp: April 16, 2016, 03:09:57 am
content: Anyone has a schematic for Uni T 33B DMM ? I have this cheap DMM and would like to increase the maximum current supply when doing the diode test. I have bunch of optoisolator that I would like to do a quick test, and it seems the DMM hits the max current limit before the led side of the opto turns on. I have test few opto with a power supply/freq gen/oscilloscope and they are confirmed good, just that when I use the DMM to do a quick test, it is not able to turn on the led side..Thank you for your help.

author: ultrasmurf
author_rank: Regular Contributor
timestamp: April 17, 2016, 09:27:57 am
content: Thanks for the suggestion blueskull. I have that a jig done up in the lab setting with freq generator and oscilloscope that can test the optoisolator. I wanted to mod my dmm to be able to do the simple led side test because most of the time if I need to do a quick test in the field, I only have my dmm with me. So far, this test has helped me to troubleshoot optoisolator/photointerruptor issue almost 90% of the time. i.e. quick confirmation that an opto/photointerruptor is not working. The rest of 10% is where I need to dismantle the pcb, come back to lab, test the opto, and find out they are ok.... Trying to cut these down, if it cannot be done, then yes I will build another small jig just to test the opto.

author: digsys
author_rank: Unknown
timestamp: April 17, 2016, 11:57:13 am
content: Generally it's not just a c/current, but a MAX voltage as well. This is why there are many DMMs that can't turn on LEDS, and others that go to 3VI'd guess that there'd be a voltage clamp or CC/CV limiter, so it may NOT be able to be done, without triggering a fault. You are better off finding a DMM thatcan go to 3V, then you can do all sorts of LEDs.

author: ultrasmurf
author_rank: Regular Contributor
timestamp: April 17, 2016, 12:45:48 pm
content: multimeter_ut33d_sch.pdf_2byultrasmurf, on FlickrAm I reading this schematic correctly ? The resistor R18 is the one that will be limiting the current when the DMM is set as a diode/continuity testing ? Seems it will be limitting the current to about 16mA for 1.5-1.6V diode.BTW, my DMM is UT33D not B as initially described, didnt have the DMM with me when I post the question.

author: Wytnucls
author_rank: Super Contributor
timestamp: April 17, 2016, 01:35:08 pm
content: Max diode test current on the 33D is unlikely to be above 1.5mA.The best meter for diode testing is the Chauvin Arnoux MTX3293, which has a Zener mode (26V 10mA), but it is expensive.
Help identifying unknown mystery device - Page 1
Forum section: electronics / testgear

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 15, 2016, 01:48:57 pm
content: Hello everybody!In another forum someone asked if anybody knows what this is, it is the only picture he posted:https://i.reddituploads.com/ce1170fa0ba143d493b1f8913e71eefe?fit=max&h=1536&w=1536&s=589725836e4ac90f155c2e066b63fb1dMy best guess so far, thermocouple meter with calibration function/output.Maybe someone here knows what it really is.Greeting,Peter

author: PedroDaGr8
author_rank: Super Contributor
timestamp: April 15, 2016, 02:20:59 pm
content: According to the internet Foster Cambridge PP332 is a portable potentiometer 20/60mV. It looks more or less identical to this one. In this case, potentiometer I think is the British meaning which is a device which measures electrical potential (ie voltage). It looks to be a null voltage model. I guess the temperature aspect is to account for temperature driift.

author: DTJ
author_rank: Super Contributor
timestamp: April 15, 2016, 02:36:51 pm
content: Pedro beat me to it!https://www.google.com.au/search?q=thermocouple+bridge&safe=off&source=lnms&tbm=isch&sa=X&ved=0ahUKEwjqq62_7pDMAhUlhqYKHdswCJ8Q_AUIBygB&biw=1920&bih=939#safe=off&tbs=ic:color%2Citp:photo&tbm=isch&q=thermocouple+potentiometer+instrumentEdit - the note on the lid appears to suggest it was used in a plant that heat treated metals.

author: SeanB
author_rank: Super Contributor
timestamp: April 15, 2016, 04:43:02 pm
content: You use this to calibrate thermocouple indicators, giving an accurate voltage that corresponds to a set temperature less the cold junction voltage. Dual use as you can also use it to set the loop resistance for use with said meter, adjusting a variable resistor to set the resistance to a predetermined value with a cold thermocouple. While you could also use it to read the thermocouple using the null meter that was really just used as a test of the thermocouple. Only time you really used that was in the calibration or verification of the unit against a more precision reference voltage source.

author: uncle_bob
author_rank: Unknown
timestamp: April 16, 2016, 12:44:16 am
content: HiBack in the days that factories were full of temperature controls based on thermocouples, these boxes were *very* common. At least a couple of dozen companies made them. Keeping a machine so it ran at the right temperature might have involved multiple calibration passes each year. If shutting down the machine meant $$$ wasted ... you bought multiple calibrators and a crew of people did the calibration in a day rather than one guy doing in in a couple weeks.There are a lot quicker / better / easier / cheaper ways to do it today. You see a *lot* of those gizmos on the auction sites. Generally they are dirt cheap compared to what they once sold for.Bob

author: PeterFW
author_rank: Frequent Contributor
timestamp: April 16, 2016, 06:26:08 pm
content: Hello and thank you everybody,now i can sleep peacefully without beeing bothered not knowing what it is!Greetings,Peter
Looking for power supply with fast current limit regulation  - Page 1
Forum section: electronics / testgear

author: michaeliv
author_rank: Frequent Contributor
timestamp: March 12, 2016, 07:14:56 pm
content: Hello,Does anyone have any good suggestions for a power supply with fast current limit enforcement.Let's say 1-10 us to settle to +- 20% when limits are set to 10V/100mA and connecting a 10 Ohm load(output needs to drop from 10v to 1v).The supplies I've tested so far seem to all have a large output capacitor after the current regulator or just have slow regulation.Cheap China power supplies seem to have a super capacitor on the output and take hundreds of milliseconds to settle.An HP E3632A takes about 35ms and an Agilent 66319B takes 3.5ms.The only thing to do well is a Keithley 220 current source which settles to +-20% in under 1us, but it's not exactly a power supply.Is there any particular reason that it's hard to design current regulation without a capacitor following it ?Thanks!

author: PedroDaGr8
author_rank: Super Contributor
timestamp: March 12, 2016, 09:19:56 pm
content: Quote from: michaeliv on March 12, 2016, 07:14:56 pmNot quite your limits but the old HP 6114A nd 6115A takes a maximum 50us to settle to within 10mV of any voltage as long as the current change is within the abilities of the supply. At 10V it should be easily able to hit what you mention.

author: kwass
author_rank: Frequent Contributor
timestamp: March 13, 2016, 03:54:40 am
content: I'm interested in this too.Here's a quick read from Keysight on this issue:part 1:http://powersupply.blogs.keysight.com/2014/11/why-does-response-time-of-ocp-vary-on.htmlpart 2:http://powersupply.blogs.keysight.com/2014/12/why-does-response-time-of-ocp-vary-on.htmlTake a look at their new, low power, E36100 supplies. Overcurent protect is claimed to be less than 1.5ms response time and transient response less than 50us. My guess is that it's much faster than this in practice, I'd be very interested to read a review of one of these supplies.

author: rodpp
author_rank: Frequent Contributor
timestamp: April 19, 2016, 01:36:53 am
content: Maybe the Keithley 2300 series can do that, it's main purpose is to simulate batteries. See below the specs of the 2304A model:TRANSIENT RESPONSE TO 1000% LOAD CHANGE:NORMAL MODE:Transient Recovery Time:<50µs to within 100mV of previous level.<100µs to within 20mV of previous level.ENHANCED MODE:Transient Recovery Time:<40µs to within 100mV of previous level.<80µs to within 20mV of previous level.Transient Voltage Drop:<100mV, typical.<200mV, typical.Enviado de meu SM-P905M usando Tapatalk

author: rodpp
author_rank: Frequent Contributor
timestamp: April 19, 2016, 02:16:31 am
content: And here is an application note talking about the load impedance effect in the PS output stability and techniques to avoid oscillations:http://www.tek.com/dl/_2870_Stabilizing_AN.pdfEnviado de meu SM-P905M usando Tapatalk

author: michaeliv
author_rank: Frequent Contributor
timestamp: April 19, 2016, 04:54:03 am
content: Quote from: rodpp on April 19, 2016, 02:16:31 amThanks, very interesting article.
Radio Shack 22-168A multimeter tear down - Page 1
Forum section: electronics / testgear

author: Rotareneg
author_rank: Newbie
timestamp: April 29, 2013, 03:54:49 pm
content: After seeing Dave tear down various multimeters I got curious as to what the guts of my old Radio Shack 22-168A meter (which is a rebadged Metex M-3650D) looks like. Please excuse the glass fuse, it did originally come with a ceramic one, but at some point I blew both it and the spare and replaced it with a glass fuse with the same rating without knowing any better.To view full size, click on the images to go the the Flickr page and then right click on the photo and choose original.]

author: david77
author_rank: Frequent Contributor
timestamp: April 29, 2013, 05:29:32 pm
content: Nice meter. I've got the Metex 3630 which has served me well for the last 13 years. I think Metex meters were quite good for the money but have nearly vanished completely in the last few years.They used to be big with the large electronics chains like RadioShack or Conrad here in Germany. Conrad has switched to rebaged Uni-T's and other Chinese cheapies.

author: Hydrawerk
author_rank: Super Contributor
timestamp: April 29, 2013, 05:54:58 pm
content: What's the purpose of the PTC1 thermistor? Well, I don't like that the white 20A fuse is hidden under the PCB. On the other hand, the PCB is not mounted to the case with screws as on my Unitrend UT70A, so it is still rather OK. Their website still exists, but it looks like frozen in time or what.http://www.metex.co.kr/According to the manual the M-3650D seems to be designed in year 1993. Somebody gave me this old machine, too. The capacitor meter is broken, but otherwise the instrument is OK.

author: free_electron
author_rank: Super Contributor
timestamp: April 29, 2013, 07:56:20 pm
content: what a funny design. they use a 7106 , which has its own display driver , tie it into a logic array and then extract bargraph and other stuff from it ...(the max130 is a pin compatible witht he 7106)

author: Hydrawerk
author_rank: Super Contributor
timestamp: April 14, 2016, 11:00:18 pm
content: Photos are unavailable.

author: Vgkid
author_rank: Super Contributor
timestamp: April 15, 2016, 07:31:08 am
content: Quote from: Hydrawerk on April 14, 2016, 11:00:18 pmwell it was uploaded 5 years ago, and op was on here 1 year ago.So
Whatisit? TDS794D on eBay - Page 1
Forum section: electronics / testgear

author: Jwalling
author_rank: Unknown
timestamp: April 14, 2016, 08:34:54 pm
content: This one is kind of interesting. I'm guessing it was one of the engineering prototypes of the TDS794D.Take a look at picture #8 with the weird serial # and the instrument name of "KILLER"Have to wonder if this one would even meet specification for a 794D...http://www.ebay.com/itm/351703008388203 views so far. I'm guessing there's some interest, but not by me.Jay

author: Jwalling
author_rank: Unknown
timestamp: April 14, 2016, 08:48:54 pm
content: Quote from: Jwalling on April 14, 2016, 08:34:54 pmAnd only 38 miles from it's original birthplace in Beaverton! That's about 2 miles per year travel rate. Carried by a fleet of slow-moving snails?Jay

author: Jwalling
author_rank: Unknown
timestamp: April 14, 2016, 08:55:39 pm
content: The more I look at this, the more I see that's weird. This scope (allegedly) has Instavue, where as the D series had DPO (yeah I know it's the same thing, basically) Didn't have time to re-do the front panel, I guess.Jay

author: AndyC_772
author_rank: Super Contributor
timestamp: April 14, 2016, 09:12:13 pm
content: I think they did... look closely and I think it says "InstaVue II" on the label, but DPO in the firmware. Guess they changed their minds about what to call it at some point during the development process.

author: nctnico
author_rank: Super Contributor
timestamp: April 14, 2016, 09:19:32 pm
content: This scope would make a very interesting teardown! One of the things which is completely unclear to me is the timeline of the TDS500 and TDS700 series. I have had a few in my hands and I have a feeling they have been making the A,B,C and D series at almost the same time.
New Home Lab Power Supply. Rigol DP832 vs BK 9130. - Page 1
Forum section: electronics / testgear

author: Lotek
author_rank: Newbie
timestamp: April 08, 2016, 11:51:24 pm
content: Hello, I am putting together my home lab and need a good triple output bench PSU. I have been steering toward the Rigol DP832 but I have a friend that will sell me a BK Precision 9130 brand new in the box for the same cost as the Rigol. I have read many reviews of the Rigol but I can't find any on the BK. Any opinions would be appreciated.Lotek

author: kendalll
author_rank: Contributor
timestamp: April 10, 2016, 07:11:45 am
content: If you're limited on bench real estate the BK unit might be preferable as it's smaller in every dimension, and almost 3 inches shorter in depth.

author: Lotek
author_rank: Newbie
timestamp: April 12, 2016, 04:59:11 pm
content: Thank you for the reply. I went ahead and purchased the Rigol.Regards,Lotek
Probe head pinout for MSO versions of DS1xxxZ - Page 1
Forum section: electronics / testgear

author: tom66
author_rank: Super Contributor
timestamp: April 14, 2016, 08:24:57 pm
content: I am curious if anyone has reverse engineered the pinout for the Rigol DS1xxxZ scopes with MSO functions. This is for a Hackspace project so £s saved matter more than time spent.The probe head is £240, and we think we can do better. I believe the connector is a simple SCSI connector (looks like HD68), the signals are differential, and there is some limited communications or voltage level setting for the head. We are also looking to find out the type of signalling (differential: ECL, CMOS, ...?) Since the signals go directtly into the FPGA I suspect it is differential CMOS of some kind, probably low voltage levels, but I am not sure.
New R&S scope - RTO2000 - Page 1
Forum section: electronics / testgear

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: April 14, 2016, 12:39:00 pm
content: It seems there's another new high-end scope on the market, this time from Rohde & Schwarz.RTO2000Brochure:https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/RTO2000_fly_en_3607_2684_32_v0100.pdfDatasheet:https://cdn.rohde-schwarz.com/pws/dl_downloads/dl_common_library/dl_brochures_and_datasheets/pdf_1/RTO2000_dat-sw_en_3607-2684-22_v0300.pdfThe basic specs haven't changed much, the analog bandwidths go from 600MHz to 4GHz with 2 or 4 channels, sample rates up to 20Gsa/s (half-channel) or 10GSa/s (quad channel), and standard memory of 100M (2ch variants, 40M on the RTO1000) and 200M (4ch variants, 80M on the RTO100), upgradeable to 2G (the old RTO1000 could be upgraded to 800M). As its predecessor, it claims a waveform update rate of up to 1M wfms/s, and offers 16bit vertical resolution via an optional 'HD' mode (software-based).Most notably is the larger screen, 12.1" WXGA (1280x800) instead of the 10.4" XGA (1024x768) display in the predecessor. This will certainly a benefit as the RTO UI is very flexible and can display a lot of information, which on the smaller screen sometimes lead to overcrowding.The RTO is an interesting scope, especially since it's supported by the R&S Vector Signal Explorer (VSE), a vector analysis software similar to Keysight's 86000B VSA. VSE can run on a separate PC or directly on the scope.I haven't found any prices yet but I guess we're roughly at $18k for the basic 600Mhz 2ch variant.
Rigol scope capture to Rigol arb gen? - Page 1
Forum section: electronics / testgear

author: TomB19
author_rank: Contributor
timestamp: April 12, 2016, 08:44:27 pm
content: If I capture a sample with my DS1054Z, can that waveform be shuttled directly to something like a DG1032Z on USB stick without any computer translation?I recall reading the Rigol wants a binary file. I suspect a Siglent generator wants something like a CSV file so that would require conversion at the PC level before being played back.This isn't a huge requirement for me, I'm just curious. If I go with something like a Siglent SDG2042X, how much will I be giving up in terms of capture/playback convenience.Thanks in advance for any info.

author: tautech
author_rank: Super Contributor
timestamp: April 12, 2016, 11:09:15 pm
content: The Siglent DSO's have the feature to capture a waveform to USB stick and then directly replicate it in their AWG's, and I'd imagine all that was required to do the same from another DSO is to capture in the same file format however I've not tried it with other brands so couldn't be sure it would work.Other members no doubt have a solution, let's hope someone sees this and points you in the right direction.

author: Mechatrommer
author_rank: Super Contributor
timestamp: April 13, 2016, 03:32:41 am
content: Quote from: TomB19 on April 12, 2016, 08:44:27 pmon DS1000Z alone, afaik there are 2 csv format variant across few fw revelations. the third (1st) variant is from the older DS1000E series, so not sure if DG1000Z can support all of them. if not, you can make a simple csv convertor for your particular case in your favorite ide language. if you are not up for programming that and a windows user,visadsocan import all three variants and export to a variant choosen the best from among of them, if the visadso's csv output is still not compatible with your DG1032Z, its just a matter of few lines worth of codes to make a convertor from visadso's csv output to DG1032Z's csv input, just PM me the sample csv input file for the DG1032Z. the flow will be dso->fg or dso->visadso->fg. however if the DG1032Z cannot accept csv, ie the input file is in binary proprietary format, than rev eng it is complicatedyou will need its bundled sw. ie the flow will be dso->sw->fg or dso->visadso->sw->fg. ymmv.

author: H.O
author_rank: Frequent Contributor
timestamp: April 13, 2016, 03:39:32 am
content: I'm not sure about the DG1032 but with the higher end DGs you can directly connect the scope and the generator via USB and the scope will show up as a USB device (ie like a thumb drive) on the generators "file browser". I would believe that saving the data to an ACTUAL USB drive instead of the internal memory of the scope would look the same to the generator. There's anapp noteon how this is done with the DS1054Z and the DG4000 series generators. The same procedure works between my DS4000 scope and DG4000 generator but again, I don't know about the DG1032.

author: TomB19
author_rank: Contributor
timestamp: April 13, 2016, 12:45:20 pm
content: This was very helpful. Thank you.