hybridfree/eevblog-posts huggingface dataset:
Bed of nails type testers - Page 1
Forum section: electronics / projects

author: Jester
author_rank: Frequent Contributor
timestamp: January 14, 2017, 06:08:10 pm
content: I have developed numerous bed of nails style testers in the past, all of them based on a generic test fixture kit something like this:http://www.robat.ltd.uk/siteimages/bedofnailspageheader.jpgI would then have the base plate drilled to match the desired points on the PCB gerber and then develop the hardware and software required for the test.The company that was provided these kits recently closed that division of the business so I'm looking for alternatives. Insomecases I could have worked with something less elaborate.Any suggestions for a source of good quality reasonably priced fixtures?

author: Krampmeier
author_rank: Regular Contributor
timestamp: January 16, 2017, 08:27:59 pm
content: I don't know in which part of the world you are living and where you want to source the test fixtures from, but I can recommend ATX (http://www.atx-hardware.de/). They have always come up with cost effective and top quality fixtures for PCBAs and other DUTs of all sizes. They can also do extras like sequential contacting from several sides, contacting of connectors, etc.Ingun (http://www.ingun.com/en) is another german supplier. We don't have a lot of experience with them, but what we have looks good and the prices are appropriate. We always use their test probes though, and they have a wide range of those an never disappointed.We have also got a fixture from EquipTest. It is big and heavy, build like a tank, for a decent price. Nothing to complain about the precision or quality, just the ladies in the production area can't lift it...All of these companies can attach a range of standard interfaces to the fixtures, such as Virginia Panel or Pylon.If you can't source from Germany, maybe the websites at least help to find the right keywords to search for suppliers in your location.

author: spudboy488
author_rank: Regular Contributor
timestamp: January 16, 2017, 08:59:40 pm
content: I use these guyshttp://hwtestproducts.com/
Been doing hobby electronics for 4 years.  For the first time I need a grommet. - Page 1
Forum section: electronics / projects

author: JoeN
author_rank: Frequent Contributor
timestamp: September 13, 2015, 01:24:43 am
content: Guess I am going to get a kit from eBay. As soon as I think I have basically everything, I find yet something else that I need to make my project work well and look professional. I could probably steal one off some old piece of equipment but I see some nice kits for about 8 bucks so why not, another kit to put on top of my kit of springs and below my kit of machine screws, I guess. I also have a kit of shrink tubing that I have used only once so far. Probably there are other little hardware kits I have forgotten and will need someday.No point. Just wanted to vent.

author: sarepairman2
author_rank: Frequent Contributor
timestamp: September 13, 2015, 06:16:36 am
content: I used a spacer kit that was sitting around for a long time. I lost a screw for my hp8904 function generator.. the spacer was not the right internal diameter but I managed to wedge it off center under the screw head to make a robust mechanical connectioni like to think of it as "hey, at least you did not blow your paycheck on a eight ball of cocaine and std tests for short lived memories"gromets are not professional unless they are inside of the chassis though.. you need nice connectors that are modular not ugly cables that come out of equipment (with exceptions).things without IEC connectors severely annoy me. I just spent 10 minutes wrangling an old power supply out of my test bench because I could not disconnect a standard cord....its a special pain in the ass if you like to ziptie things and arrange your cordsjust bought a grommet kit btw lol
Beer can SMD stencils, lets develop this technology - Page 1
Forum section: electronics / projects

author: hlavac
author_rank: Frequent Contributor
timestamp: September 06, 2013, 01:42:08 pm
content: I really like the idea of making solder paste stencils out of beer/soda cans. It is cheap and has the right thickness.However the problematic part in this is getting the protective layer off the aluminium sheet.It is so resistant that the only way to remove it that really works reliably is sandpaper and lots of work.And then you need to re-apply the etching mask again. And it takes off the thickness of the thin sheet.I am looking into alternative ways to do this cheaply and easily. I want to actually use the protective layer.I have found that I can leave the protective layer as is and scratch out the outlines of the holes with a needle and then etch it.The inner parts will fall out nicely, however would probably have to do it from both sides otherwise the protective layer on the other side remains and holds it in place.I think I will attempt to create a tiny little XY plotter device with a needle to try this.I want this to have really high resolution (0.05mm or less). I think its too small to mill out.Maybe an oscillating needle? I don't need to actually pierce the aluminium, just damaging the protective layer so that the etchant can get thru would be good enough...Do you have any other ideas how to pierce the protective layer in any other ways? How about some sparks?I could make some sparks with an inductor, but how do I prevent the high voltage from frying the switching element?

author: dr.diesel
author_rank: Super Contributor
timestamp: September 06, 2013, 01:44:06 pm
content: Who drinks beer out of a can?
before the FAX analog picture transmitter via phone or radio - Page 1
Forum section: electronics / projects

author: oz2cpu
author_rank: Frequent Contributor
timestamp: August 23, 2025, 03:08:09 pm
content: sometimes i score some more odd or rare units,this one is a picture transmitter using analog tones for phone or radio links,it is from about 1983model : muirhead beckenham k-570-bit uses really interesting optical solution, fiber, photo multiplierjust to mention a little bit of the main components,again i made a little video so show and share all my findings :https://youtu.be/KDDvCbUzIZc

author: Terry Bites
author_rank: Super Contributor
timestamp: August 23, 2025, 06:51:36 pm
content: Mr Muirhead invented the fax. The facsimile transmitter was a big deal for the newspaper business. Putting a picture "on the wire" changed the face of newspapers forever.They had a factory in Elmers End very near to Beckenham, London. I used to walk by it every day on my way to school. It was an impressive piece of architecture and a local landmark. Sadly, it was demolished in the 1990s to make way for a sh*te hotel.They had a reputation for quality and precision. It great to see one of their professional fax machines working. Put it back together and test it with HylaFAX.The company morphed into an avionics outfit. They make black boxes and whatnot.www.muirheadavionics.com

author: madires
author_rank: Super Contributor
timestamp: August 23, 2025, 07:21:08 pm
content: https://en.wikipedia.org/wiki/Faxtells a different story about the developement of the fax. BTW, there's also SSTV (Slow Scan TV).

author: oz2cpu
author_rank: Frequent Contributor
timestamp: August 23, 2025, 08:43:40 pm
content: i just heard my machine was used for reporters in the field,who will take develop and then transmit pictures within a few hrs in total,amazing tech in 1983
Before there was EEV there was EEB (old magazine archives) - Page 1
Forum section: electronics / projects

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: February 26, 2015, 10:23:11 am
content: The Australian EEB magazine that is.Ten years' worth of a quirky experimental electronics magazine published by a Hobart university professor can be found at:http://www.rochester-engineering.com/EEB/Numerous projects, theory articles, circuit ideas and more. Sort of like Talking Electronics but covers a wider field and pitched at more experienced readers.Its articles were frequently quoted in bigger electronics and radio publications of the time (but, rarely, if ever, in Electronics Australia, etc).(The publisher later moved to Melbourne and very recently passed away)

author: EEVblog
author_rank: Unknown
timestamp: February 26, 2015, 10:40:00 am
content: Never heard of that one! thanks for pointing it out.

author: vk3yedotcom
author_rank: Frequent Contributor
timestamp: February 26, 2015, 11:18:36 am
content: One of the many topics covered was modulated light beam transmission. It is referred to athttp://www.bluehaze.com.au/modlight/LongArticle1Jan79.htmThe funeral notice of the publisher was athttp://tributes.theage.com.au/obituaries/theage-au/obituary.aspx?n=elaine-mary-foster&pid=173401427Two longer obituaries appeared in Amateur Radio magazine, March 2015.

author: nixxon
author_rank: Frequent Contributor
timestamp: February 26, 2015, 12:13:36 pm
content: Quote from: vk3yedotcom on February 26, 2015, 11:18:36 am"Elaine Mary Foster (AKA Ralph Leo Gunther Silent Key)"
Behaviour of transient response when PM and cross-over frequency changes - Page 1
Forum section: electronics / projects

author: Patrick66
author_rank: Regular Contributor
timestamp: April 17, 2024, 09:06:13 am
content: Hello everyone, I'm currently building an LED driver using type one compensation and I simulated the output current with different phase margins and cross-over frequencies to study the response of the system. The result that I got is when the phase margin decreases the cross-over frequency increases and the percentage of overshoot as well as the time to reach transient decreases but the damping increases. Wanted to ask whether this situation is normal? If the result is correct, if possible can you explain why is this situation like this. Thank you in advance and sorry for my ignorance.
Belden 4855R termination with Neutrik NBNC75BDD6X - Page 1
Forum section: electronics / projects

author: ryanwp
author_rank: Newbie
timestamp: September 09, 2021, 02:15:46 pm
content: Hi,Im trying to terminate belden 4855R cable with Neutrik NBNC75BDD6X. However the bonded foil is causing me intermittent faults when testing. Has anyone ever terminated these? Any help would be greatly appreciated.
BEMF measurement for sensorless BLDC control - Page 1
Forum section: electronics / projects

author: anvoice
author_rank: Frequent Contributor
timestamp: March 26, 2018, 06:35:03 am
content: Trying to decide how I'll be implementing the commutation sequence on my BLDC motor controller. So far I'm leaning towards sensorless motors, so I'll need to measure the back emf at the floating coil to figure out when to switch the PWM signals. Information is fairly scant, but I found several sources that describe techniques for BEMF measurement. The sources are:https://www.digikey.com/en/articles/techzone/2013/jun/controlling-sensorless-bldc-motors-via-back-emfand an application note by Microchip (AN1160).The application note in particular discusses an algorithm for measuring a virtual neutral point of the BEMF to figure out the zero crossing, and using the ADC on the MCU to measure the attenuated BEMF at each coil. A second approach to figuring out the zero crossing is to use comparators and a virtual neutral point set up through a resistor network, but the ADC approach seems to offer some advantages in terms of noise isolation.My main question is: how would I go about estimating the values of the voltage divider to measure the BEMF, if I don't yet know what that BEMF will be? Is measuring it my only option?A secondary question is: are there alternative methods for BEMF measurement that could be better, or perhaps advantages to the comparator approach?Thanks for reading.
BEMF sense - Page 1
Forum section: electronics / projects

author: amirkargar110
author_rank: Contributor
timestamp: June 15, 2017, 12:36:07 pm
content: helloI want to design a brushless sensorless BLDC speed controller.I put a voltage divider and a low pass filter for sensing BEMF Zero cross sense. and then I connect its output to 3 channels of ADC.do you think that is enough and effective?my micro is STM32F030K6T6 and it does not have analoge comprator.do you think adc speed is enough for this work or I put a zero cross circuit like the figure and connect it to a timer input?

author: ali_asadzadeh
author_rank: Super Contributor
timestamp: June 15, 2017, 01:04:46 pm
content: Welcome to the forum,why do you need a zero cross circuit? besides that I think you should use a current sense circuit with X amplification and using a compactor, or you can use the ADC reading the Back-emf, there is a feature inside the MCU that's called analog watchdog! so you will set it's limit to the desired voltage and if the adc readings pass the certain window level it would generate an interrupt, but the problem with this approach is that there would be a lot of adc samples that you are in the zero crossing section, so maybe with some software trick you could disable the analog watch dog and re-enable it after the PWM pulse!these are just plain Ideas.-
Bench DVM Project for Home Construction? - Page 1
Forum section: electronics / projects

author: Chris56000
author_rank: Frequent Contributor
timestamp: February 22, 2018, 08:57:04 pm
content: Hi!I still feel there's a need for an easy–to–build mains–powered Bench DVM Project that's midway between the "el–cheapo" 3.5 digit designs and the Rigol's, Siglents, etc.Does anyone know of a more recent self–contaimed mains DVM for home construction than the one published by two Polish doctors in the April/May 1979 issues of Practical Electronics, such as a 4.5 digit one using the ICL7136 or a PIC?I ask because the medium–priced Keithley (175, 177, 195, 197, etc.,) dvms are starting to get very high priced as well as tatty now, with more and more of 'em sold for hefty postage feeds or from Israel with all the Customs penalties buying T & M from that country that entails!I'm thinking of a 4.5 digit 19,999 or 3¾ digit 3999 count design by the way!Are the modern multi–function surface mount dvm ICs suitable for adaption to LED displays?Chris Williams

author: jbb
author_rank: Super Contributor
timestamp: February 22, 2018, 09:37:03 pm
content: This could be fun.I’m not aware of any recent kit designs, but I am aware (courtesy of our host Dave) that there are several standard chipsets available, with application notes etc.I can say that the safety issues are non-trivial (unless you choose low ratings): think about input protection, choice of fuses, mechanical design of enclosure, shielding, power and data isolation.I suspect (not know, suspect) that kits can be EMC and safety rated provided that the instructions are good enough and the parts kit includes every single safety critical component (I.e. there must be every opportunity for the builder to do it right). This probably includes a machined / injection molded enclosure. I suspect that a print-your-own enclosure would not be acceptable.Also, a benchtop DMM would generally have a bunch of relays for range setting instead of a rotary dial. These will add a surprising amount of cost to the design. (Also they tend to have special requirements which make for complicated drivers.)

author: ogden
author_rank: Super Contributor
timestamp: February 22, 2018, 10:05:57 pm
content: Quote from: Chris56000 on February 22, 2018, 08:57:04 pmWhy do you want4.5 digitbench DVM? I believe that 4.5 digits is handheld territory. Just get EEVBlog 121GW or checkmultimeter spreadsheet.Circuit of complete DVM is too complicated to be attractive for DIY builders. Such build most likely will not save you any money. It have to be calibrated as well. I started 5.5 digits DIY voltmeter (50v/5v/500mV/50mV) thread, but it did not get much traction and dried out.

author: jbb
author_rank: Super Contributor
timestamp: February 23, 2018, 01:12:03 am
content: Quote from: ogden on February 22, 2018, 10:05:57 pmThis is a good point. There would be a lot of parts and complexity, and I wouldn’t be surprised to find that such a kit costs as much as a Rigol or Siglent unit.
Bench Power Supply - Page 1
Forum section: electronics / projects

author: jamessinghal
author_rank: Contributor
timestamp: February 28, 2018, 05:34:42 pm
content: Hey eevblog,I have been working on the design for my bench power supply, and need help finding a useful schematic for it. I have been basing it off of the LT1084, but the schematic on its data sheets contains 2 transformers without information about them. My main requirements are at least 0-30v and at least 0-5a. I mostly have the voltage control done, but the part that I can't figure out is the current limiting control. I don't want to use a potentiometer because of efficiency, and I want to use something similar to the circuit that a mainstream power supply (BK precision or Rigol) uses to accurately limit the current.Any help is welcomeThanks,James

author: jamessinghal
author_rank: Contributor
timestamp: February 28, 2018, 11:25:28 pm
content: I found the LT3080 but don't know how to effectively use it. Are there any other good schematics for lab power supplies?

author: CopperCone
author_rank: Super Contributor
timestamp: March 01, 2018, 05:26:02 pm
content: Dave jones had an entire seeries on his early usupply using lt3080

author: cellularmitosis
author_rank: Unknown
timestamp: March 02, 2018, 06:57:28 am
content: Didn't he run into a problem with the LT3080? Was he ever able to figure out a solution? Something like it became unstable under certain conditions? It seemed like it killed his uSupply project.
LT3080 output drop compensation - Page 1
Forum section: electronics / projects

author: MarkSvrc
author_rank: Newbie
timestamp: December 11, 2020, 09:29:27 pm
content: Hey guys, I am new here at the forum.I am currently building a linear bench power supply whose main part, the voltage regulator, is the well-known lt3080 that e.g. Dave Jones used in his own design. I am running into a bit of trouble now as when i was testing the lt3080, the regulation seemed to be quite poor. While I have made sure to measure the voltage directly across the regulator tap and the COM of the circuit, i might have very well still miss something.But whatever the cause of the voltage drop may be, I have decided that just relying on the regulator to maintain the stabilized voltage and on the internal connections not to drop much of it is not the proper way to do it. So i was thinking and came up with the idea of providing the op amp follower with a voltage feedback for the inverting input directly from the OUTPUT regulator rail instead of the SET pin like you can see in the picture below.As i am using pots to set voltage and the arduino to read the output terminal voltage ONLY, compensating for the voltage drop with it the digital way is not an option for me.What i want to ask you guys is, do you think that this confuration could really work and that the lt3080 would now provide better load regulation? I don't really need that much of a clean ramp up but don't want the output to overshoot significantly before the opamp stabilizes itself. [ Specified attachment is not available ]edit#1: For anyone having a similar issue with the regulation of LT3080 - I badly underestimated the importance of adding low ESR output Capacitance. Problem solved!

author: Benta
author_rank: Super Contributor
timestamp: December 11, 2020, 09:43:16 pm
content: Quite frankly, I question your use of a breadboard here.At least set up your circuit on a perfboard, anything less is complete rubbish.Breadboards are for playing with a transistor, an LED and a couple of resistors, nothing else.
Bench power supply project - Page 1
Forum section: electronics / projects

author: cncmoose
author_rank: Newbie
timestamp: October 26, 2012, 07:40:12 pm
content: Has the bench power supply project ever been completed? Is there a single location for the information to build it?Thanks,Leland

author: Michaelo
author_rank: Newbie
timestamp: December 15, 2015, 01:37:09 am
content: I know it's been some time but was wondering if anyone has any info on the bench power supply... even a schematic for rev b or c?Failing that, if anyone could point me towards a design for a good bench supply (0-20 volts @ 2 amps)... Many thanks...Mike

author: AustinEngy
author_rank: Regular Contributor
timestamp: December 15, 2015, 01:56:02 pm
content: He has posted the schematics for Rev B and C. There's no PCB file available that I'm aware of, so you're out of luck on that front, I believe.Rev B:http://www.eevblog.com/files/uSupplyBenchRevB.pdfRev C:http://www.eevblog.com/files/uSupplyBenchRevC.pdf

author: dom0
author_rank: Super Contributor
timestamp: December 15, 2015, 02:32:15 pm
content: It might be a starting point for the precise requirements he wanted to fulfill (mainly running of single supply batteries and very small size = low power dissipation), but for a general purpose, mains powered bench supply the design is unsuited.
bench PSU 0-->15V 0-->3A - Page 1
Forum section: electronics / projects

author: Ahmed_MK
author_rank: Newbie
timestamp: June 26, 2024, 04:45:03 pm
content: I watched a couple of videos on lab power supplies by Dave and I tried to attempt to make my own.*check attached imageI am a beginner and It is my first electronics project.I have not finalized it.However, I have a couple of questions on OP-AMPS and On the way I attempted to get negative voltage.1. In the data sheet for the op-amps it says "All voltage values, except differential voltages, are with respect to the midpoint between VCC + and VCC −"and it says Vcc =( + or - ) 18V.does that mean I could put +28.6V volts and -1.4V such that the range is less than 36V?*I would do that since the opamps used are not rail to rail2. Also, Proteus fails to simulate this circuit, it says too many iterations.Furthermore, I would appreciate any advice you can give me?Appreciated

author: mikerj
author_rank: Super Contributor
timestamp: June 26, 2024, 06:30:46 pm
content: Quote from: Ahmed_MK on June 26, 2024, 04:45:03 pmYes, the supply rails do not have to be balanced. Having a small negative voltage rail is reasonably common to allow the output of the op-amp to swing down to a true 0v.I have no idea about Proteus though I've never used it, sorry.

author: Benta
author_rank: Super Contributor
timestamp: June 26, 2024, 11:05:56 pm
content: Why not just use a TI LM350K?You'll need a negative bias voltage to get it down to 0 V output, but that's a nice little exercise.To generate a negative supply voltage, this little circuit is great. You just need to make sure that the main (positive) supply line pulls more current than the negative.
Bench PSU from ATX PSU Question - Page 1
Forum section: electronics / projects

author: Ohmzilla
author_rank: Contributor
timestamp: December 19, 2016, 12:12:37 am
content: First I want to thank you to all the experts around here and Dave for inspiring me to start doing my own small electronics projects.My question is the PSU I am converting to use on the bench has a standard 115v ---> 230v selection switch. Inside the supply, two wires run from the switch to the PCB of the unit. I would like to minimize the clutter inside the unit as much as possible. I have no intention of ever using the higher voltage setting, would the supply function as intended if I simply removed the leads from the board?Thanks!!

author: IanB
author_rank: Super Contributor
timestamp: December 19, 2016, 12:18:37 am
content: It depends whether the switch is open or closed when in 115 V mode.If the switch is closed in the 115 V setting and you remove the wires from the board you will effectively open the switch and put it in 230 V mode. So you should figure out what the switch does before deciding to disconnect it.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: December 19, 2016, 12:23:13 am
content: Hate to be there bearer of bad tydings, but the way these things are configured, if you remove the switch the supply will be permanently set to 220v.Sorry.

author: jeroen79
author_rank: Frequent Contributor
timestamp: December 19, 2016, 12:31:31 pm
content: You could figure out what is opened and what is closed in the 115V position and then replicate that with a few wires soldered close to the board.

author: Fungus
author_rank: Super Contributor
timestamp: December 19, 2016, 12:49:11 pm
content: Quote from: joseph nicholas on December 19, 2016, 12:23:13 amIf the switch needs to be closed you can replace it with a piece of wire.

author: madires
author_rank: Super Contributor
timestamp: December 19, 2016, 01:39:48 pm
content: Usually the switch connects the link between the two filter caps in series to L, just in front of the bridge rectifier. If closed this creates a voltage doubler, i.e. 115V input. The switch for voltage selection also implies that there's no active PFC.
Bench supplies in 2015... - Page 1
Forum section: electronics / projects

author: 6sigma
author_rank: Newbie
timestamp: February 11, 2015, 12:39:55 am
content: Back in 2011 Dave talked about bench power supplies in his video #168 - How to set up an electronics lab. He gave some features for his ideal power supply, but didn't specifically name a design, kit or manufactured supply as a favorite.Considering his thoughts about multi-turn pots, dual tracking, mains isolated, adjustable current, 15V - 1A, load switch, etc., did or does a favorite bench power supply emerge as the "go to" supply for hobbyists?I've searched and read lots of threads here, but haven't found the "Hakko FX888D" of power supplies.Is there one in 2015? [Thanks for any help you can provide.]

author: nowlan
author_rank: Frequent Contributor
timestamp: February 11, 2015, 01:20:54 am
content: Used agilent or power designs since you're in America.E3610Afor example.Otherwise, its still the Chinese Korad style if your buying new, or possibly the Rigol 832 if you need the features.Keep in mind what you need the power supply for. If its microcontrollers, you wont need big power/voltage/current necessarily.You may not need dual tracking for amplifier/opamps.Most just need current control, and possibly output toggle switch.

author: 6sigma
author_rank: Newbie
timestamp: February 11, 2015, 01:53:31 am
content: Thanks for the info...nowlan. With cellphones & computer accessories changing every ten minutes, I'd assumed bench power supplies might have changed a bit over several years. Your advice helps.
Bench Testing AC Transducer - Page 1
Forum section: electronics / projects

author: am1
author_rank: Contributor
timestamp: April 01, 2024, 04:35:04 pm
content: Hi all,I have a AC current transducer that I want to bench test to ensure I am getting a 4-20mA output. I am using a AE001 unit. It is very simple, with only an M12 cable that I have wired the following way: L+ on 24V supply of PLC (brown wire) , L- on GND of PLC (blue wire) , and IO-Link output of PLC (black wire). I am using an X20DS4387 IO-link module. When I wire and power my PLC, I get no output when live monitoring my PLC. I am unsure how to externally bench test this as there are no terminals on this CT like other transducers I have worked with.(https://autosen.com/en/Condition-Monitoring/AC-current-sensors/Current-sensor-with-IO-Link-AE001)For context I previously used an ACT050-42L-F with an IFM DP2200 wired the same way to my PLC that worked well. With no load, I see an output of 4.0 mA. My goal is two eliminate these two components with this one sensor. I am new to instrumentation so all advice is appreciated. Thanks!I do not have a lot of testing/measuring instruments aside from a basic MM, basic signal generator, and a variable PS. See below:https://www.amazon.com/Adjustable-Generator-Simulator-Controller-Calibration/dp/B0991ZSBHJ/https://www.amazon.com/SHNITPWR-Universal-Adjustable-Switching-100V-240V/dp/B08N4R48LJ/

author: jwet
author_rank: Frequent Contributor
timestamp: April 01, 2024, 06:01:11 pm
content: I looked at Manual, black wire is the IO-Link out (Out 1). 4-20 mA is on out 2, the white wire.

author: am1
author_rank: Contributor
timestamp: April 01, 2024, 06:35:02 pm
content: Ah, I was was under the impression that the IO-link output would take take of the signal conversion of 4-20 to a IO signal. Unfortunately the only analog input module I have is for +/-10V signals (X20AI4222). I have this IO-Link module (X20DS4387) that can operate as IO-link or standard input/outputs, so I wanted to see if it would be possible to get my output while eliminating the converter. But I guess a convertor is needed if I am using this hardware?

author: jwet
author_rank: Frequent Contributor
timestamp: April 01, 2024, 07:07:22 pm
content: A work around could be a 500 ohm precision resistor across your input.
Bench - Page 1
Forum section: electronics / projects

author: Electronics Engineer
author_rank: Newbie
timestamp: August 07, 2017, 07:24:51 am
content: General Chat on electronics lab benches.

author: Electronics Engineer
author_rank: Newbie
timestamp: August 07, 2017, 07:26:14 am
content: what is a good height, width, depth, material for a good electronics bench

author: CM800
author_rank: Frequent Contributor
timestamp: August 07, 2017, 03:24:09 pm
content: Quote from: Electronics Engineer on August 07, 2017, 07:26:14 amDo you plan on sitting or standing?Do you plan on putting heavy things on it?Do you want a shelf or not to put your equipment on?

author: Nuno_pt
author_rank: Frequent Contributor
timestamp: August 07, 2017, 05:03:35 pm
content: Dave has some great videos on how to do a bench, we talks about height and the sitting vs stand up.https://youtu.be/vuUSIt3rbyUhttps://youtu.be/GMRvEA8rgJsI'm renewing my bench and will follow some of Dave advices, the bench will be 3.60m long, 1.20m deep and 0.90m height.The 0.90m (90cm) height will work for both working will standing up or when sitting down on a stool like Dave uses.

author: smithnerd
author_rank: Regular Contributor
timestamp: August 08, 2017, 12:19:39 am
content: This is what I usually make. I build rigid sets of leg pairs (front and back legs) of a suitable size to support whatever material I want to use for the top. If I build those like tanks, then I only have to worry about ensuring that the bench can't rack over. I like to use 1/2" mortice and tenon joints, pulled up tight with a suitable coach screw.This is a rough working drawing for one I'm building at the moment, out of recycled timber.

author: smithnerd
author_rank: Regular Contributor
timestamp: August 08, 2017, 01:30:22 am
content: A metalworking bench which I made a while ago, slightly beefier.The extra supports under the worktop were unnecessary. It has 3/4" plywood shelves sitting over the bottom part, which are not shown. I calculated the height based on the top of my bench vice coming to just below my elbow in a standing position.If you build a standing bench, make sure you get a stool with height adjustment.
benchtop gap (electro) magnet - Page 1
Forum section: electronics / projects

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 20, 2020, 07:43:00 pm
content: Hi all!I'm currently constructing a ~3500 Gauss magnet for some physics shennanigans, and I'd like some pointers.General topology should be similar to this:So a yoke holding 2 pole pieces, and either coils or permanent magnets. Field strenght should be ~3500 G (0.35T), over at least a 5 mm^2 area. Preferably 10 mm^2. The gap between the poles must accomodate a section of WR-90 waveguide (narrow side).Here's the most important design criterion: It CAN NOT be a hulking monster that draws 3 kW, needs water cooling and weighs tonnes.I can't decide whether to go with electromagnets or permanent NdFeB magnets, in the latter case, a tune coil is also needed to be able to move the field strenght slightly.Either way, multiple sets of smaller coils for field modulation will be introduced lastly, possibly epoxied to the pole pieces.There's a brilliant software package called FEMM to simulate magnetic fields, that could be used to rough in dimensions.I'd also like to have the yoke be fabricatable without needing to get a machine shop involved.What do you think? Electro or electro tuned permanent?Thanks in advance.

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 20, 2020, 09:47:01 pm
content: I've salvaged a large 3.5 cm thick toroidal transformer core, unfortunately it is one long piece of steel band - I'd thought about either drilling through it to hold it together or put some radial welds down each side. Would this provide a viable yoke, or should I scrap that idea?

author: ChristofferB
author_rank: Frequent Contributor
timestamp: August 20, 2020, 09:59:53 pm
content: Alternatively something like this:The slight gap beneath each magnet could of course be filled somehow.
Benchtop Step Up / Down XFMR w/ Outlets - Page 1
Forum section: electronics / projects

author: klr5205
author_rank: Regular Contributor
timestamp: February 27, 2017, 02:13:29 pm
content: I'm surprised to be having difficulty with this...My company has several step up transformers similar to this onehttps://www.amazon.com/Simran-AC-3000-Voltage-Converter-Transformer/dp/B004MPR44E/ref=sr_1_10?ie=UTF8&qid=1488204219&sr=8-10&keywords=simran%2Bvoltage%2Bconverter&th=1... and I have been less than impressed with the quality. I'd like to research an alternative, but for some reason I've been having trouble finding anything that isn't a blatant rip off of this exact design. Aside from generic google searches I've looked at companies like Staco and BK Precision to see if they had any offerings with no luck so far, so I figured I'd ask the hive mind. The primary useage is to run European equipment in the US. (There is no voltage switch on the back and it doesn't use a removeable IEC plug)So how about it? Has anyone heard of a decent step up / down transformer like the one in the link? Our current units are 5000W rated but less may be adequate.

author: IanB
author_rank: Super Contributor
timestamp: February 27, 2017, 02:22:41 pm
content: Fry's sells them in all different sizes in the Philmore brand. I can't say the quality will be anything other than "generic mass market" though.

author: helius
author_rank: Super Contributor
timestamp: February 27, 2017, 02:58:24 pm
content: I would recommend buying a 4-winding transformer (the "Universal transformer") and hooking it up yourself to the correct rated cords and outlets. The commercially available small converters are autotransformers, so are not isolating, and who knows whether they use the cheapest available sockets.

author: klr5205
author_rank: Regular Contributor
timestamp: February 27, 2017, 05:50:26 pm
content: Quote from: helius on February 27, 2017, 02:58:24 pmIn the longer term that's exactly what I plan on doing, however I was hoping to purchase something off the shelf to get us through the spring outage season. I will be traveling quite a bit over the next couple months and won't have time to properly design and document something until I return.I've opened Simran converter linked in the original post. It does have a proper transformer in it, but that's about all it has going for it. To your point the outlets are cheap and sometimes intermittent and the soldering is bad to the point that we inspect every new one we purchase for broken wires / poor solder joints. Those quality issues and the fact that a GFCI breaker would be more appropriate or us are what have me looking around for a replacement.
Benefits of Interleaved SMPS? - Page 1
Forum section: electronics / projects

author: ShaunAndFRED
author_rank: Contributor
timestamp: February 27, 2013, 11:13:21 pm
content: Hey EEVForumers,I'm currently designing a relatively high power (~1.5kW) SMPS for a weekend project. I was wondering if anyone had input on the benefits of interleaving 'n' converters. I'm assuming one of the major benefits is the distribution of heat through multiple inductors and MOSFETS, and a more sable output voltage, but I can't seem to find too much material on the subject. Any wisdom or pitfalls to avoid would be much appreciated!

author: rbola35618
author_rank: Frequent Contributor
timestamp: February 28, 2013, 03:11:42 am
content: There are two advantages that I can think of. If you interleace a SMPS and run then each at 100KHz, then your output filter does not have to be so large because at the output the frequency will double to 200 KHz.You get the same benefit at the input filter. The current spikes the you try to suppress and keep way from getting into the inout bus will be attenuated becuase they are at double the frequency. Therefore, you inout filter can be smaller.Robert

author: bfritz
author_rank: Regular Contributor
timestamp: February 28, 2013, 05:57:15 am
content: Believe it or not, this wikipedia article item on multiphase bucks captures the ideas well.http://en.wikipedia.org/wiki/Buck_converter#Multiphase_buck
Benefits of side plating for sensitive circuits - Page 1
Forum section: electronics / projects

author: johofz
author_rank: Contributor
timestamp: April 22, 2021, 09:41:17 am
content: Hello dear EEVblog-Community,I'm currently designing a prototype for a charge mode amplifier used to convert the charge coming from a piezoelectric force/torque sensor.Since charge mode amps are very sensitive, I thought about applying side plating to the PCB, but I'm not sure if it's worth the extra cost considering it's only a prototype. It would essentially cost almost 3x as much.I'm dealing with a sensitivity of 3.7pC / N and designed the amp to produce 1V at 10kN. Since it's the first charge mode amp I designed, I'm not 100% sure but It does not seem like a very critical situation in therms of SNR.One more thing that is typically suggested is to use guard-rings on the inputs of the opamp. Again I have no previous experience whether it is necessary or not in my case.Any advice would be greatly appreciated!Greetingsjohofz

author: T3sl4co1l
author_rank: Super Contributor
timestamp: April 22, 2021, 10:31:48 am
content: A ground plane and via stitching (with a via fence if you're feelingreallyparanoid) is more than adequate.Tim

author: RoGeorge
author_rank: Super Contributor
timestamp: April 22, 2021, 10:54:45 am
content: - Guard rings for op-amps, yes, preferably servo driven so the Vinput to Vring is always zero.- Side plating, IDK, probably not.- You'll need to shield the prototype board anyway, sometimes double shielding it, and sometimes magnetically shielding it, too, depending on the working environment.

author: johofz
author_rank: Contributor
timestamp: April 22, 2021, 11:25:57 am
content: I decided to use the via fence and a guadr ring around my critical input nodes. I connected the Ring to the reference voltage. is that correct?Also i read somewhere, that i have to place the guard on the bottem layer aswell if I have through hole components like the test points.Here is the 3D View of the layout:The other inputs of the opamp are for buffering and an preamp to an adc. Should I guard them too? I nevr did sofar and no problems occured. I'm just paranoid since i never dealt with charge amps before.

author: coppercone2
author_rank: Super Contributor
timestamp: April 23, 2021, 05:45:44 pm
content: if you have trouble you can try to dead bug solder it with through hole components where possible and compare your results to the PCB, it may come out cheaper then prototype iterationsI had great results with dead bug soldering a LMC6001 or whatever that electrometer op amp is, you only have R&C circuits so you are set, and even better if you can get a through hole version of the chipit should offer the maximum possible leakage performance, those datasheets for electrometer parts often like if you float things above the PCB if possible for you
Benefits of transformer output for lab. frequency reference? - Page 1
Forum section: electronics / projects

author: Illusionist
author_rank: Regular Contributor
timestamp: September 08, 2019, 06:46:09 pm
content: I'm designing the output stage for my 10MHz GPSDO. So far I've narrowed down the sine wave output op amps to either AD8052 or LM7171 (mostly because I have some of both).On some designs I've seen on the 'net, the output is transformer coupled for 'isolation' (that's all that was said about it). I have some Minicircuits transformers that would suit (T1-1T-KK81+), but I don't really understand what the benefits and drawbacks are. Other than DC isolation of course, with the drawback that I then have to somehow insulate the output sockets from the (grounded) metal panel of my enclosure. Is there anything else I should know? Is it really useful? I'll be using the GPSDO as a reference to the usual suspects in my home lab.Also, where would I put ESD protection (CM1213A I think)... on the primary or secondary side?

author: edpalmer42
author_rank: Super Contributor
timestamp: September 08, 2019, 10:45:14 pm
content: In addition to the DC isolation you mentioned, transformer outputs break low-frequency ground loops (typically mains frequency) which can mess up low level or high precision measurements.One thing to remember is that you should still have a parallel resistor/capacitor path between the shield and ground. The capacitor gives you high frequency coupling to ground so that the shield can still act as a shield. The resistor gives you a high value DC ground path to bleed off any charge on the shield. I don't know if there is any concensus on what the component values should be. One Rb standard that I know of (Efratom FRT) omitted the resistor and used 6n8 capacitors.If you use BNC connectors, it's really easy to find cheap isolated, panel mount, female connectors.Ed

author: Illusionist
author_rank: Regular Contributor
timestamp: September 09, 2019, 08:18:11 am
content: Thank you for that. I'll stick with the transformers.Yes, a quick search turned up some isolated BNC connectors. In fact I think I even have some, somewhere.
Beryllium copper vs. A2 stainless crinkle washer for connecting PCBs - Page 1
Forum section: electronics / projects

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: June 13, 2018, 01:09:45 pm
content: Question for metallurgists:I'm fixing two (ENIG) PCBs together with nylon snap rivets for a mechanical +electrical joint.Using a crinkle washer between to maintain tension for a reliable contact against any long-term creep etc.I can buy A2 stainless or beryllium-copper crinkle washers - which would be best and why?

author: voltsandjolts
author_rank: Unknown
timestamp: June 13, 2018, 01:13:27 pm
content: Beryllium-copper is toxic in some forms. Don't file the washers!

author: hayatepilot
author_rank: Frequent Contributor
timestamp: June 13, 2018, 01:22:43 pm
content: It depends on how much current has to pass through the joint. Stainless has a pretty bad electrical conductivity.Even better are toothed lock washers (also known as serrated washer or star washer) like those used on grounding lugs.

author: free_electron
author_rank: Super Contributor
timestamp: June 13, 2018, 02:59:55 pm
content: If it really must be reliable : PEM nut. punch it in the board and done.i would not trust dissimilar metals. depending on environment and what is in the air ....

author: donmr
author_rank: Regular Contributor
timestamp: June 13, 2018, 03:31:23 pm
content: Are you passing current through this washer or just using it to hold the boards and some connectors together?

author: Unknown
author_rank: Unknown
timestamp: June 13, 2018, 06:39:33 pm
content: Interesting. I never heard of a PEM nut. Here's some info from a google search:https://www.pemnet.com/fastening_products/pdf/kdata.pdf

author: dmills
author_rank: Super Contributor
timestamp: June 13, 2018, 07:44:57 pm
content: Wurth do a version in 1mm height increments which can sometimes be convenient (IIRC PEM SMT ones are in 2mm height increments).Regards, Dan.

author: langwadt
author_rank: Super Contributor
timestamp: June 13, 2018, 08:06:06 pm
content: Quote from: hayatepilot on June 13, 2018, 01:22:43 pmstar washer on a pcb sounds like a really bad idea

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: June 13, 2018, 09:44:42 pm
content: Nylon is so stretchy that even a bellville washer would be unreliable over time. fix the boards together with standard steel or brass hardware and loctite, or use locknut.
Best 5V Boost Circuit from 4.2V Li-ion - Page 1
Forum section: electronics / projects

author: jamiec
author_rank: Contributor
timestamp: January 23, 2017, 12:27:20 pm
content: Hi,I have been struggling with getting 5V from a 4.2V lithium battery.I have designed a PCB circuit with a TPS61200DRCT 0.5A Boost Converter however I am having reliability issues.When the pcb is powered cycled very quickly the Regulator goes closed circuit at the input (Not good for a Li-ion battery) or the5V shorts out.I was going to re-design the circuit but was wondering if anyone has any schematics / layouts they would be willing to help with?There is so much variety in boost converters for things like usb battery bank that I am sure there must be a reliable method.The maximum current I need is 0.5A.Thank you

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 23, 2017, 02:25:55 pm
content: If it is for hobby use, just use an ebay module. Very cheap. Ok for 0.5 a.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 23, 2017, 04:53:07 pm
content: With a module like this one, for 0.36$, you can charge and discharge your lithium cell, with a charge and discharge protection.http://www.ebay.com/itm/10PCS-Micro-USB-5V-1A-18650-Lithium-Battery-Charger-Board-With-Protection-Module-/131747731497?hash=item1eacc6d829:g:1G4AAOSwvg9XdxhIYou certainly cannot build anything that will beat the price.

author: Codebird
author_rank: Regular Contributor
timestamp: January 23, 2017, 05:06:59 pm
content: How are you doing the power cycling? If it's a mechanical switch, perhaps the bounce is causing the converter to lock up.

author: Ian.M
author_rank: Super Contributor
timestamp: January 23, 2017, 05:09:52 pm
content: If you have MLCC decoupling capacitors at the input to a power conversion circuit or regulator, and the supply voltage is over half of the semiconductor's max rated input voltage, failures at power on due to excessive voltage caused by the decoupling capacitance ringing with the supply and ground leads self inductance are very common.The cure is to either add TVS clamping to keep the ringing under the max voltage rating, or to add inrush current limiting, or to add damping e.g. by adding a second decoupling cap with a 1R resistor in series with it.

author: jamiec
author_rank: Contributor
timestamp: January 25, 2017, 12:38:06 pm
content: Quote from: Ian.M on January 23, 2017, 05:09:52 pmSorry for the long reply, I didn't realise anyone had replied because I thought it would email me.I think this very much sounds like the issue I am having. The Voltage regulator is designed for maximum 5V input and I am driving from a 3.7V Li-ion (Max 4.2V). I will certainly look at TVS clamping or adding in a second decoupling capacitor.Thank you very much for the information.

author: jamiec
author_rank: Contributor
timestamp: January 25, 2017, 12:39:22 pm
content: Quote from: Codebird on January 23, 2017, 05:06:59 pmI am using a standard SPST switch to switch on the regulator,ThanksJamie