hybridfree/eevblog-posts huggingface dataset:
JTAG iimplementation SW - for the Arduino Nano v3.0 mini board ? - Page 1
Forum section: electronics / projects

author: roli_bark
author_rank: Regular Contributor
timestamp: January 10, 2014, 08:36:44 am
content: Is there a recommended SW (firmware) for the Arduino Nano v3.0 (ATMega328 based) mini board - that implements JTAG ?Thanks

author: bingo600
author_rank: Super Contributor
timestamp: January 10, 2014, 08:50:01 am
content: Do you want to debug the chip , or make the chip a jtag dongle ?This chip can not be debugged via jtag/Bingo

author: roli_bark
author_rank: Regular Contributor
timestamp: January 10, 2014, 12:10:26 pm
content: Yes - I know it can't be debugged via JTAG.So, the latter - making the Nano v3.0 a JTAG device.Thanks

author: clifford
author_rank: Regular Contributor
timestamp: January 10, 2014, 03:37:18 pm
content: Depends on what you are trying to do with JTAG. If you want to use it as JTAG programmer that can play SVF/XSVF files you can use my libxsvf library (http://www.clifford.at/libxsvf/) to implement something based on the xsvftool-gpio.c example.If you just want to have a low-level jtag interface you might be interested in the following blog post by pesco:http://www.khjk.org/log/2013/aug/jtagbang.html

author: roli_bark
author_rank: Regular Contributor
timestamp: January 11, 2014, 05:59:48 am
content: Thanks for the 2 links. Useful.
JTAG TDI TDO and UART Connections for FPGA - Page 1
Forum section: electronics / projects

author: HasanSyr
author_rank: Contributor
timestamp: March 30, 2025, 07:38:49 pm
content: I'm creating my own FPGA development board. I'm trying to use both USB and header pins for JTAG/UART debugging/programming.Im confused on this part, though, does TDO connect to TDI and vice versa? The FT2232 datasheet labels ADBUS1 as "TDI/DO" "Output" and ADBUS2 as "TDO/DI" "Input", all FPGA board schematics have a net label of "TDI" on ADBUS1 and "TDO" on ADBUS2. I'm guessing the actual pins on FT2232 are TDO and TDI respectively and they are connected to TDI and TDO respectively but at the same time the net labels on the Pynq-Z2 label ADBUS1 as "FT2232_TDI"?Finally I want to ask if I have connected the labels in my schematic in the correct order in parallel, or does it even matter if they are in parallel? Note: the JTAG header pins are supposed to be compatible with the Xilinx Cable, again does TDI connect to TDO here? What should I label the UART pins on the PCB?

author: HasanSyr
author_rank: Contributor
timestamp: April 01, 2025, 10:55:31 am
content: On a Xilinx board schematic the TDO and TDI are switched on the FTDI ADBUS1 and 2 pins! But others have TDI and TDO?
Judging the output of a filter - FFT - Page 1
Forum section: electronics / projects

author: atferrari
author_rank: Frequent Contributor
timestamp: January 28, 2015, 08:03:38 pm
content: A square signal (variously pre-filtered / buffered), enters the same type of filter trying to get the best approach to a sinewave of3960Hz.CorrectedFor four different topologies, LTSpice gives the attached FFT. My questions:Which one is the best in terms of purity no matter if that "best" is still a poor one? Could anyone tell briefly what are the main points to know which one is?How do you judge the height of the harmonics against the height of the fundamental? Or is it the wrong way to see this?Additional comments appreciated.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: January 28, 2015, 08:19:44 pm
content: With a square wave, the problem is harmonics (especially the odd ones). You should quantify the amplitude of all (or at least the first few) versus the fundamental for each filter. eg:Filter 1:2nd harmonic: -15 dB3rd harmonic: -10 dB4th harmonic: -20 dBFilter 2:2nd: -16 dB3rd: -8 dB4th: -22 dBetc.Which one is "best" depends on what you're going to be doing with the signal, and which harmonics are more/less detrimental in your application.And you do know that none of those are anywhere near 1980 Hz, yes?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 29, 2015, 05:29:33 am
content: Step response isn't a good way to test a filter. Use an AC Analysis.Step response is for when you want to test the time-domain characteristics: how flat is the step response, overshoot/ringing, rise time, those things. These are directly at odds with the frequency response (a sharper frequency response necessarily has more ringing in the time domain, while a faster risetime with no overshoot has a very soft frequency response).Tim
Jump starting the DW01 - Page 1
Forum section: electronics / projects

author: Peabody
author_rank: Super Contributor
timestamp: July 30, 2022, 05:36:35 pm
content: The DW01 is a lithium battery protection chip. The typical application circuit is attached below. When a battery is first connected, the protection mosfets may come up in the off state. One version of the datasheet has this notation:Note: When a battery is connected toDW01 for the first time, it may not enterthe normal condition (discharge maynot be enabled). In this case, short the CSand VSS pins or connect to a charger torestore to the normal condition.Some refer to this as "shipping mode". I participated in a thread on this subject:https://www.eevblog.com/forum/projects/pain-and-suffering-getting-the-dw01-and-8205a-protection-circuit-work-right/msg1838381/#msg1838381which didn't really come to a conclusion about how to deal with this "feature". I think it could be a problem when changing batteries in the field, and would like to find a way to make the chip come up in normal mode (discharge enabled) when the battery is first connected. So I wondered if anyone else has dealt with this, and if so, how.Experimenting with the typical TP4056 charger modules which have protection included, I find that they will come up in normal mode if there is no load (other than my meter leads), but with 100R across the output, I have to plug in the charger before it will come up. After that it runs fine with or without the charger - so long as the battery stays connected.In the thread referenced above, one participant said he got it to work by reducing C1 from 100nF to 80nF. But I don't know if he tested various load conditions, and I have no idea how or why this would work. Another suggestion was to install a capacitor from CS to GND (pin 2 to pin 6), presumably to temporarily ground CS, which the Note suggests might work. I don't know if anyone has tried this (I haven't).Anyway, I just wondered if anyone is aware of anything definitive on this - a way to make sure it comes up enabled, or for that matter to make sure it doesn't. I have one circuit using the typical circuit for this chip that does come up enabled, even with a load, but I don't know why because a second copy doesn't.
Jumper for 125MHz - Page 1
Forum section: electronics / projects

author: luky315
author_rank: Regular Contributor
timestamp: November 23, 2023, 08:42:30 pm
content: I need something to manually select between 2 clocks, one of them is 50MHz and the other one 125MHz. I have never used a classic 3 Pin header with a jumper for this frequency range, but I am expecting problems. So what would be a simple, mechanical alternative which performs better?

author: tooki
author_rank: Super Contributor
timestamp: November 23, 2023, 09:08:37 pm
content: I doubt it’ll be a problem, 125MHz isn’t all that fast.Alternatives/variations:-headers and jumpers smaller than 2.54mm pitch-small SMD DIP switch-small SMD SPDT slide switch-solder jumper-simple circuit using jumpers to control some logic gates to select the clock electrically

author: PCB.Wiz
author_rank: Super Contributor
timestamp: November 23, 2023, 09:09:07 pm
content: Quote from: luky315 on November 23, 2023, 08:42:30 pmWhy do you expect a 3 pin header to be a problem ? It's not 125GHz.You could always pay a little bit more, and go for a 2mm jumper, which has a smaller footprint. You can even buy 1.27mm shunts/jumpers.

author: moffy
author_rank: Super Contributor
timestamp: November 24, 2023, 11:09:37 pm
content: If using a jumper, which should be fine, you might want to surround the header with ground plane, to reduce emissions. The 125MHz is not that high but the edges are pretty fast if we are talking square wave/logic signals.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 24, 2023, 11:18:35 pm
content: It shouldn't be a problem unless the jumper itself is really loose.One problem I see with that though, if you're using TH jumpers, is the antenna effect of the pin header. Outputting a clock on a pin header can ruin EMC. Done and tested.So I would favor a solder jumper.

author: Terry Bites
author_rank: Super Contributor
timestamp: November 26, 2023, 02:20:39 pm
content: CK make a nice little switch TDD01H0SB1R, will you feel the benefit. Probalby not.
jumper or shorting link help - Page 1
Forum section: electronics / projects

author: Thorn1979
author_rank: Newbie
timestamp: December 14, 2021, 12:45:13 pm
content: I can't be looking for something *that* unusual but perhaps someone can point me in the right direction.I need to link out two terminals on a connector. Because this is on a product that will be sold, it needs to be tidy - so I don't want to use a bit of wire to do the job. I'm looking at doing 20 to 50 of these at a time so I was hoping there's be a jumper or link that'd do it, but I have searched high and low. I think maybe it's a nomenclature thing - this really is not my background, sorry.I need to join terminals 1 and 4 (in a row of 11), missing out 2 and 3. Pitch is 5.08mm. I can find things that will link two adjacent terminals, but nothing that will miss terminals out.Does what I want just... not exist? I looked at using pin header and cutting off the 2 middle pins, then bridging the other two, but that's more fabrication work that I am trying to avoid.Any suggestions?! Thanks!!Alison

author: ajb
author_rank: Super Contributor
timestamp: December 14, 2021, 04:16:34 pm
content: Any particular connector?I doubt you'll find something like that off-the-shelf, such things exist for larger systems like DIN mount terminal blocks, but general connector systems are another story.I don't think a wire jumper is that untidy, it's not unusual at all to see that sort of thing. I just repaired my dishwasher and it had exactly that on one of the control PCB connectors, and I recently finished a project at work where an optional interface needs to be jumpered when not in use, so we're just shipping it with some wire jumpers pre-fitted to the terminal block plug, and 90%+ of customers will leave it that way. Of course the dishwasher control PCB is completely enclosed in the appliance, and our product is rack mount equipment, so the connectors are well protected. If your product is handheld or something, then yeah, a wire loop could be an issue.If there's a PCB mount version of the connector you need, then you could just make a simple PCB that does the jumpering. I also did that in the same work project, since the main PCB supports varying combinations of IO boards. If there's an SMT connector that works for you it may even be possible to do a nice silkscreen label on the backside that says what it is. For a PTH connector you might want a bit of epoxy or something to encapsulate the pins on the back side or something.

author: Terry Bites
author_rank: Super Contributor
timestamp: December 14, 2021, 05:19:05 pm
content: Insertion Bridge. Phoenix contact and others.https://uk.farnell.com/search?st=insertion%20bridge
Jumper selection - Page 1
Forum section: electronics / projects

author: jpwack
author_rank: Contributor
timestamp: October 04, 2010, 07:08:33 pm
content: Good morning everyone:Recently I've seen some designs jumping fromye olde0.1'' jumper to solder jumpers (which look like a SMD resistor pad, with a tiny wire in between to be cut or resoldered).The benefits I can see are:- Cost 0- Only one side of the PCB is usedThe drawback is:- No easy manipulation (or impossible w/o knife and soldering gun)Anyway, which is better for general use? Temporally I'm sticking with the classics, but for the "almost always default" scenario I'm having doubts.Cheers!

author: Simon
author_rank: Unknown
timestamp: October 04, 2010, 07:38:15 pm
content: well it really depends n your use of the jumper, if you want it as a user selectable thing it has to be a real jumper, if it's a case of your doing a mass produced thing and want to alter the functioning just before shipping go for the solder jumper, for example you have to have real jumpers on a motherboard or they would be a waste of time

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 04, 2010, 07:38:58 pm
content: On my TAP-28 board, which is aimed more towards dedicated applications as opposed to a traditional development board, I used solder jumpers to connect LEDs, switches and pullup resistors into the circuit. There were two considerations:The jumpers were not likely to require changes once configuredThe cost of traditional pin jumpers is not insignificantA side benefit is that solder jumpers don't take up much space on the board.If the application may require changes during its life, especially if used by people who may not have a soldering iron handy, then the traditional jumpers are the best answer. If the jumpers will be fixed after programming, solder jumpers are a good alternative.TAP-28 PIC Applications Board

author: TheDirty
author_rank: Frequent Contributor
timestamp: October 05, 2010, 01:44:20 pm
content: It seems pretty straightforward. Solder bridges are useful for configuration items that hardly ever change. Sparkfun seems to do a lot of these since they have generic modules that solder bridges can be used to manage the functionality.

author: Neilm
author_rank: Super Contributor
timestamp: October 05, 2010, 05:57:53 pm
content: I have seen these used on boards that were laid out with star pointed ground system. It allowed the designer to use the PCB layout software to route the differing 0Vs and keep dedicate where the grounds joined. Now most boards with any significant logic are using ground planes with a common 0V throughout the board this practice is dying out.Neil

author: Jon Chandler
author_rank: Frequent Contributor
timestamp: October 05, 2010, 06:33:18 pm
content: Those 0.1" jumpers are surprisingly costly too. At Digikey, they are between 10 - 50 cents each and more. That starts to add up on a board with many jumpers.Another consideration if the jumpers never need to be changed by the end-user: it's something that somebody who is poking around may change, creating problems.
Junction Temperature - Page 1
Forum section: electronics / projects

author: sanwal209
author_rank: Regular Contributor
timestamp: July 21, 2017, 03:09:13 pm
content: Hi,I have been trying to calculate the junction temperature of some automotive high side switches by infineon and i couldn't find any theta (?j) in the Datasheet.Following are Part Numbers:1. BTS6163DAUMA12. BTS740S2XUMA13. BTT62004EMAXUMA1Is there any other way to calculate the junction temperature and heat resistance ?Thanks

author: georges80
author_rank: Frequent Contributor
timestamp: July 21, 2017, 03:27:38 pm
content: Well, your first part has the info, I assume the rest do too (in the datasheet)cheers,george.
Just an interesting paper from TI - Page 1
Forum section: electronics / projects

author: Terry Bites
author_rank: Super Contributor
timestamp: October 13, 2022, 04:49:46 pm
content: https://www.ti.com/lit/SLYY200Some noteworthy stuff for those of us that like a quite psu.

author: niconiconi
author_rank: Frequent Contributor
timestamp: October 13, 2022, 06:34:24 pm
content: QuoteAnalog Devices also has a product line called Silent Switcher 2, which also uses an improved packaging technique like TI's. In addition to low inductance footprint, ADI's packages also use embedded capacitors for low-ESL bypassing.These certainly are great innovations, but on the flip side (no pun intended), the use of low-ESL, high density QFN and BGA packages makes an otherwise routine repair of a power supply rail become a tricky and challenging task.But I guess any technology comes at its own cost.

author: ogden
author_rank: Super Contributor
timestamp: October 13, 2022, 07:03:39 pm
content: Quote from: niconiconi on October 13, 2022, 06:34:24 pmDo not blame manufacturers but consumers who do not care how repairable devices are and how long they last - at the time of the purchase. Manufacturers just offer what is demanded by market.
Just Another Buck Boost Bench Power Supply Project - Page 1
Forum section: electronics / projects

author: jonovid
author_rank: Super Contributor
timestamp: January 19, 2021, 08:36:22 pm
content: using buck boost converter module &50 watt halogen desk lamp transformerbench power supply projectthis case design without a cooling fan is good for 2ampsbuck boost converter module can work up to 4 amps with a fan.usesbicballpoint pen case as part of push button switch
Just another LM317 Power Supply - Page 1
Forum section: electronics / projects

author: Madsaaby
author_rank: Regular Contributor
timestamp: December 22, 2012, 03:18:40 am
content: Hi GuysJust recently did a new case for my old home-build power supply, and thought i would do a biginners guide on how to build a very simple supply.Here is a link if anybody is interested:http://ec-projects.com/index.php?side_id=13If you do actually read all this, please let me know if you get any value out of it.- Mads

author: mianchen
author_rank: Regular Contributor
timestamp: December 22, 2012, 01:05:18 pm
content: I think it's quite wordy, not many people have the attention span to read this much nowadays, more pictures would be better, or just do a video. However, more wordy is better for google search, at least it's true up until now. You could keep the words but do an video on top...just my personal opinion...

author: JoannaK
author_rank: Frequent Contributor
timestamp: December 22, 2012, 01:11:12 pm
content: Yep. Well known design, it works and is easy to build. That 7-segment Led-display looks nice.

author: Harvs
author_rank: Super Contributor
timestamp: December 22, 2012, 01:14:04 pm
content: Might want to check that reference to a TO-2 package. Maybe I'm wrong, but pretty sure you're talking about the good old TO-3.

author: Madsaaby
author_rank: Regular Contributor
timestamp: December 22, 2012, 04:44:04 pm
content: Quote from: Harvs on December 22, 2012, 01:14:04 pmThanks Harvs, Dont know where TO-2 came from :S It is ofcause the TO-3 as you mentioned. I will correct that

author: Madsaaby
author_rank: Regular Contributor
timestamp: December 22, 2012, 04:52:20 pm
content: Quote from: mianchen on December 22, 2012, 01:05:18 pmThanks for the feedback. I am planing to do a video of it, and I want to change the hand drawn images with proper ones, but ran outatimeI do have a few photos I can add, so I'll do thatI was also afraid it would be too much talk and too less action, so I'm thankful for the feedback-Mads

author: Madsaaby
author_rank: Regular Contributor
timestamp: December 22, 2012, 04:57:42 pm
content: Quote from: JoannaK on December 22, 2012, 01:11:12 pmYes, it's almost the exact schematic from the datasheet..I build this a few years back, with very little electronic knowledge, and I've used it quit a lot. And yep, it just works. Thanks-Mads

author: jancumps
author_rank: Unknown
timestamp: December 22, 2012, 06:40:04 pm
content: Quote from: Madsaaby on December 22, 2012, 04:52:20 pmLeave the hand drawn please. Much more fun to look at.

author: Madsaaby
author_rank: Regular Contributor
timestamp: December 23, 2012, 04:03:54 am
content: Quote from: jancumps on December 22, 2012, 06:40:04 pmOkay, I could do that, but I still want to redraw the AC vs Rectified one. To be showing the correct voltagesThanks for the feedback !-Mads
Just copped this $20 touch screen thermostat on Aliexpress, thoughts?  - Page 1
Forum section: electronics / projects

author: patrikcarlsson
author_rank: Newbie
timestamp: November 15, 2016, 09:15:06 pm
content: What's up guys so I just received this $20 thermostat from a seller on Aliexpress (https://www.aliexpress.com/item/230V-underfloor-16a-LCD-programmable-touch-screeen-digital-heating-thermostat-room-temperature-controller-for-heating-systems/32605299002.html) to be used for my floor heating, and of course the first thing I did was to take it apartand I was actually really surprised how it looked just as well made, or possibly better than my previous thermostat that went bang a couple of weeks ago (cap had vented in it for some reason), and that exact model still costs about $80 here in Sweden.Here is an album of pictures of it:https://imgur.com/a/a7Ab0So do you guys have anything negative (or positive for that matter) to point out about this thing? Is the 1.5mm creepage between the incoming live and load enough? I just connected it to my floor heating and it seems to work great! Menu system is nice with a big clear display, the relay is quiet, lots of settingsHere in Sweden you have to pay about $150 for a similar one.

author: Messtechniker
author_rank: Frequent Contributor
timestamp: November 16, 2016, 06:12:34 am
content: Since it carries a VDE mark you might want to verify it here:https://vde4you.vde.com/DE/INSTITUT/ONLINE-SERVICE/VDE-GEPRUEFTEPRODUKTE/Seiten/Online-Suche.aspxCrepage (German: Kriechstrecken) details here:http://www.mikrocontroller.net/articles/Leiterbahnabst%C3%A4nde#Mindestkriechstrecken_bei_Leiterplatten

author: LukeW
author_rank: Frequent Contributor
timestamp: November 16, 2016, 06:17:31 am
content: That relay carries a VDE mark, but that's just that component that they've used - not the overall system.
Just help me get my head around filtering noise from this power stage - Page 1
Forum section: electronics / projects

author: Simon
author_rank: Unknown
timestamp: July 05, 2023, 08:21:46 am
content: I have a brushless motor driver. It generates some noise on the power line I assume. When I power a control circuit from the same power line at a certain point things start to jump all over the place and the control circuit becomes useless.My options seem to be:1) put a differential choke on the motor drive - big and expensive, takes lots of space and there is no need if it is not otherwise hindering EMC2) put a common mode choke on the control circuit. But I'm not sure how this helps, the problem will be the ground bouncing all over the place with the positive dipping in tune. Not a huge issue as we reduce 50V down to 5V but the ground jumping up and down is likely the issue as anything attached to the control circuit by a wire like sensors misread. This system is floating and the noise is not common mode to the control circuit supply that I can tell.3) use a differential choke on the power input to the control circuit, but this will not stop the ground jumping around.4) use a differential choke on the ground to put some separation between the powerful ground that is jumping about and the power ground of the control board5) put a differential choke on both ground and power, this to me seems sensible.Signals from the control system to the power system are galvanically isolated.

author: Jeroen3
author_rank: Super Contributor
timestamp: July 05, 2023, 08:29:15 am
content: Jumping around typically means position encoders report incorrectly. Are you using shielded cable from the driver to the motor?Or twisted pair for the encoders?Does you galvanic isolated circuit have y-capacitors to decouple any noise it picked up?

author: moffy
author_rank: Super Contributor
timestamp: July 05, 2023, 08:45:48 am
content: Normally I would say eliminate the noise at the source, the BLDC drive it usually proves to be the best course of action in the long run, especially if extra devices are added to that line. But if you want to go with 5, and it's relatively easy then just try it out. The bouncing ground, do you have the neutral bonded to earth as we do in the antipodes of Australia, I am unfamiliar with the ground in Britain?

author: Simon
author_rank: Unknown
timestamp: July 05, 2023, 11:46:32 am
content: The whole system is floating. The motor drive is perfectly happy, but the control board is not when sharing it's cower, when the control board is powered from a separate supply the whole thing works.
Just received free samples of Analog Devices ADCs - any experiences? - Page 1
Forum section: electronics / projects

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: February 11, 2021, 07:27:17 pm
content: I just received two free samples from Analog Devices of their LTC2357CLX-16#PBF:Analog to Digital Converters - ADC Buffered Quad, 16-Bit, 350ksps Differential +/-10.24V Input SoftSpan ADC with Wide Input Common Mode Rangehttps://www.digikey.com/en/products/detail/linear-technology-analog-devices/LTC2357CLX-16-PBF/7929469I was wondering if anyone has any experience with them. In particular, they are packaged to prevent moisture exposure and labeled with lots of warnings about temperatures, baking etc. For hand-soldering, what precautions are needed re. moisture? They are 48-LQFP.

author: thm_w
author_rank: Super Contributor
timestamp: February 12, 2021, 12:08:57 am
content: Hand soldering, no precaution needed.If you were reflowing, would make sense to leave the bag sealed until assembling the board (see "mounted within" statement on the label). But for hobbyist purposes, even that is not critical.

author: JohnnyMalaria
author_rank: Super Contributor
timestamp: February 12, 2021, 12:24:07 am
content: Quote from: thm_w on February 12, 2021, 12:08:57 amThank you - good to know

author: JoeyG
author_rank: Regular Contributor
timestamp: February 12, 2021, 12:49:54 am
content: It just means solder them on the PCB as soon as possible after they are exposed to air (humidity/moisture).If you leave them out of the bag for some time then it will be harder to solder the ic's pads,**The BAG says MSL 3 **Moisture_sensitivity_level is a rating on how long before you have to dry the ic when the bag is openhttps://en.wikipedia.org/wiki/Moisture_sensitivity_levelThis notificaion is aimed at production houses
Just some 0.4mm pitch BGA rework - Page 1
Forum section: electronics / projects

author: TommyGunn
author_rank: Contributor
timestamp: June 10, 2014, 11:04:28 pm
content: Just had to do some rework and i figured I would film it.

author: marshallh
author_rank: Unknown
timestamp: June 10, 2014, 11:22:52 pm
content: Pretty intense

author: TommyGunn
author_rank: Contributor
timestamp: June 10, 2014, 11:24:51 pm
content: It is. Can't drink coffee when I do this. But a beer always helps.
Just starting out really, my new hobby - Page 1
Forum section: electronics / projects

author: lordvader88
author_rank: Frequent Contributor
timestamp: December 28, 2016, 05:48:42 am
content: I've barely built built anything over the 2 past year of watching videos on this stuff. Once and a while I'd go back over some 1st year stuff like KCL, KCL, nodal and mesh analysis on paper. And learned a few new things from books and videos. Over the years I dabbled in Maxwell's Eq's, even into the tensor level and Clifford Algebra side of it all. I come from a physics background.Anyways last night I finally threw together a poorly designed buck converter driven by a 555 timer running at 155kHz. I only used 2 equations and in the end I dropped ~8.2V down to 7.6V. And I took it all apart. I was more surprised my Vici VC99 said parts of the 555 circuit were actually at ~155kHz.And I've barely used my Tektronix DSO, but yup I measured the frequency from that and calculated ~152kHz.Soon I'll build it back up and make it better.Over this past 1-2 years I bought lots of analog and logic chips that I've barely played, so lots of fun ahead, especially as I get more and more idea what I'm doing, and actually remember the stuff I learn for more than a day or 2 and then forget.Onwards and upwards, this is far more productive than playing video games.

author: jaromir
author_rank: Unknown
timestamp: December 28, 2016, 09:09:24 am
content: The fact you calculated the frequency to be 155kHz and it was indeed 155kHz is a bit of luck on your side, as addition to calculations. Coming from physics background it is natural to calculate first and then doing the experiment, but this can also lead to somehow sub-optimal results, when it comes do design efficiency, to say at least.I worked with physics guys a lot and often they struggled with buying 7,519kOhm resistor, because calculations told them so. It is the opposite side of "throw components on bench and tweak it until it works" approach, which is bad as well. The usual engineering approach is something in between and taking the right balance for the given task is skill that is honed for years.Good luck with your hobby; it can be very frustrating sometimes, though the physical result of hobby (=having device that blinks, beeps, walks or whatever) is something can give you more satisfaction than hobby in "virtual" world. Check out also the "beginners" subforum here.
JX10-0315RDNL ethernet jack with magnetics - Page 1
Forum section: electronics / projects

author: nuclearcat
author_rank: Unknown
timestamp: April 22, 2019, 07:36:06 pm
content: 12 pin, with yellow and green LED.Nothing on all datasheet engines i searched, google and etc.I found JX10-0045NL-ND и 0061, but they are quite different, so i expect 0315 to be different too.And searching compatible without the diagram how magnetics are connected i guess impossible.Any help on this?
K-12 student $20 scope circuit - Page 1
Forum section: electronics / projects

author: Mephitus
author_rank: Regular Contributor
timestamp: January 07, 2016, 06:06:45 pm
content: Original page:http://www.ece.utah.edu/~ecectools/_Outreach/_Outreach.htmPDF:http://www.ece.utah.edu/~ecectools/_Outreach/StephenSiebOscilloscope/SSieb20DollarOscRev2.pdfI was looking around the locally available free EE curriculum and found this rather nifty little circuit project for a PIC controlled andvery verybasic scope. Thought it would be worth posting for others to use or have as a starter educational project. There are other circuits and such available on the link above. Share and enjoy!

author: eugenenine
author_rank: Frequent Contributor
timestamp: January 08, 2016, 09:51:35 pm
content: Amni reading that correct that they are connecting the pic's ground to 5v?

author: SPRX
author_rank: Regular Contributor
timestamp: January 08, 2016, 11:22:33 pm
content: eugenenine, it is correct. PIC Gnd should be connected to +5v to achieve specified input of -4.5 to +4.0 V. In the schematic, input Gnd id is also connected to +5v

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: January 08, 2016, 11:53:34 pm
content: Hi,Don't trust somebody who wires the protection diodes like this:Jay_Diddy_B

author: LukeW
author_rank: Frequent Contributor
timestamp: January 09, 2016, 12:01:16 am
content: Quote from: eugenenine on January 08, 2016, 09:51:35 pmIt might be easier to get your head around it if you "rename" the +5V rail to ground, the ground to -5V and the +9V rail to +4V.Still looks like a very dodgy design though.

author: Andy Watson
author_rank: Super Contributor
timestamp: January 09, 2016, 12:24:34 am
content: Quote from: Jay_Diddy_B on January 08, 2016, 11:53:34 pmLooks like whoever drafted the schematic was having a bit of an "off" day. The button/switch inputs apparently sense the "+5V" ground.I'm sensing undergrad group-project write-up !
K-Type Thermocouple Spice Model - Page 1
Forum section: electronics / projects

author: veryevil
author_rank: Unknown
timestamp: February 09, 2019, 11:25:40 am
content: Hi, I'm looking for a spice model (LTspice preferably) for a K-type thermocouple.Anyone have one or clever enough to make one from NIST tables?Cheers

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 09, 2019, 10:59:10 pm
content: How would you want that, with a TEMP input pin? Otherwise you have to specify device temp which is really only usable with parameter sweeps I think...Have you looked around for one? Wouldn't surprise me if it's out there for free, it's easy enough.I could write one but it'd be a few hours work writing and testing... maybe someone else here has the spare time to?Tim

author: veryevil
author_rank: Unknown
timestamp: February 10, 2019, 03:15:35 am
content: Hi, the only one I could find was a J type. I managed to modify it with the correct polynomial for a k-type and it's working.I was going to post it on here but forum was out most of yesterday.When I get back to my computer I'll post it.Thanks

author: veryevil
author_rank: Unknown
timestamp: February 11, 2019, 08:12:17 am
content: Code:* K-Type thermocouple subcircuit for LTSpice* Using reference function on ITS-90 (International Temperature Scale of 1990)* Temperature range: -270.000 to 0.000 degC* 0.000 to 1372.000 degC** Tjunc = Input voltage representing the thermocouple junction temperature* | Tref = Input voltage representing the cold-junction temperature* | | Vtc+ =* | | | Vtc- =* | | | |.SUBCKT TC_K 1 2 3 4*E_TJ 5 0 VALUE = { IF(V(1) <= 0,+ 0.000000000000E+00 ++ 0.394501280250E-01*V(1) ++ 0.236223735980E-04*V(1)**2 ++ -0.328589067840E-06*V(1)**3 ++ -0.499048287770E-08*V(1)**4 ++ -0.675090591730E-10*V(1)**5 ++ -0.574103274280E-12*V(1)**6 ++ -0.310888728940E-14*V(1)**7 ++ -0.104516093650E-16*V(1)**8 ++ -0.198892668780E-19*V(1)**9 ++ -0.163226974860E-22*V(1)**10 ,+ -0.176004136860E-01 ++ 0.389212049750E-01*V(1) ++ 0.185587700320E-04*V(1)**2 ++ -0.994575928740E-07*V(1)**3 ++ 0.318409457190E-09*V(1)**4 ++ -0.560728448890E-12*V(1)**5 ++ 0.560750590590E-15*V(1)**6 ++ -0.320207200030E-18*V(1)**7 ++ 0.971511471520E-22*V(1)**8 ++ -0.121047212750E-25*V(1)**9 ++ 0.118597600000E+00*EXP(-0.118343200000E-03*(V(1)-0.126968600000E+03)**2) ) }*E_TR 6 0 VALUE = { IF(V(2) <= 0,+ 0.000000000000E+00 ++ 0.394501280250E-01*V(2) ++ 0.236223735980E-04*V(2)**2 ++ -0.328589067840E-06*V(2)**3 ++ -0.499048287770E-08*V(2)**4 ++ -0.675090591730E-10*V(2)**5 ++ -0.574103274280E-12*V(2)**6 ++ -0.310888728940E-14*V(2)**7 ++ -0.104516093650E-16*V(2)**8 ++ -0.198892668780E-19*V(2)**9 ++ -0.163226974860E-22*V(2)**10 ,+ -0.176004136860E-01 ++ 0.389212049750E-01*V(2) ++ 0.185587700320E-04*V(2)**2 ++ -0.994575928740E-07*V(2)**3 ++ 0.318409457190E-09*V(2)**4 ++ -0.560728448890E-12*V(2)**5 ++ 0.560750590590E-15*V(2)**6 ++ -0.320207200030E-18*V(2)**7 ++ 0.971511471520E-22*V(2)**8 ++ -0.121047212750E-25*V(2)**9 ++ 0.118597600000E+00*EXP(-0.118343200000E-03*(V(2)-0.126968600000E+03)**2) ) }*E_TC 3 4 VALUE = { (V(5)-V(6))/1000 }*.ENDS
K40 Laser Power supply "Power Adjust" in. - Page 1
Forum section: electronics / projects

author: Detzi
author_rank: Regular Contributor
timestamp: April 11, 2019, 03:05:18 pm
content: Hi there,the supply of my K40 Laser crapped out so i wanted to take the opportunity and upgrade the electronics.The original configuration uses a potentiometer connected between +5V and GND and the wiper is connected to the "IN" labeled pin on the PWR-Supply. Since the "Datasheet" of the supply states that also a PWM could control this input i did hook up a PWM-Out to this pin.Now i could notice that this "IN" puts out 5V. Confused as i am i took the thing apart and here i am even more confused asking if someone can explain what is happening here: please have a look at "sch.png" in the attachements.The Chip used is a TL494CN which error amplifiers are used and hooked up to this Input. It's Datashet shows no internal connection to "3" the output, nor can i find a connection elswere on the board made to "3". Which input could possibly be on "1" that this makes sense? I do have to miss a connection internally or externally right?Thanks for having looked in hereand thanks in advance for your help.

author: texaspyro
author_rank: Super Contributor
timestamp: April 12, 2019, 04:01:40 am
content: Did you connect your foot to the machine chassis? Was your foot bare or wearing socks and/or shoes?

author: radix
author_rank: Contributor
timestamp: April 13, 2019, 11:30:18 am
content: Have a look at page 10 of the datasheet.http://www.ti.com/lit/ds/symlink/tl494.pdfThe amplifier outputs are connected to the PWM comparator.As for pin 1, I would expect it to be connected to some kind of a feedback network. This would be compared to your reference input (the PWM or DC voltage).

author: Detzi
author_rank: Regular Contributor
timestamp: August 15, 2019, 01:02:53 pm
content: Just for the sake of completeness.If someone ever wants to know more, have a look here:https://www.digikey.com/schemeit/project/k40-lps-7S9UFV0201F0/@radix:Thank you! Somehow i did not notice your post untill now. If i had, it would have helped me a lot, and it is the solution!
KA3525/SG3525 - Capacitor Softstart - Page 1
Forum section: electronics / projects

author: aless2056
author_rank: Contributor
timestamp: April 21, 2022, 06:25:49 pm
content: Guys, if I don't use pin 8 of the SG3525 (softstart function) should I leave it open or grounded?

author: strawberry
author_rank: Super Contributor
timestamp: April 21, 2022, 06:55:04 pm
content: floatinggrounded will shutdown (0 PWM)https://www.onsemi.com/pdf/datasheet/sg3525a-d.pdf

author: aless2056
author_rank: Contributor
timestamp: April 22, 2022, 01:05:55 am
content: I once saw a circuit in which there was a resistor with a value of 10K between pin 8 (softstart) and pin 16 (Vref). I spent weeks wondering why the use of this resistor, I could never understand. Does anyone have the idea why they put such a resistor?

author: strawberry
author_rank: Super Contributor
timestamp: April 22, 2022, 04:07:19 am
content: internal pull up current source might not be enough in some case for noise immunity
KAA12580625H ic - where can I find the datasheet? - Page 1
Forum section: electronics / projects

author: avitsur
author_rank: Contributor
timestamp: January 21, 2024, 02:32:22 pm
content: This KAA12580625H ic is in an atx power supply. googling it yield two results from Russian sites, but unfortunately no datasheet found, that led me to believe that it is a Russian product even though the psu is Chinese. any idea where I can find it's datasheet?

author: wraper
author_rank: Unknown
timestamp: January 21, 2024, 02:45:53 pm
content: Are you sure you're searching a correct part number? Isn't it actually 2005Z?

author: avitsur
author_rank: Contributor
timestamp: January 21, 2024, 03:20:03 pm
content: Yes, it is. my fault, I just found out that the correct part no. is 2005z.Any idea if it's possible to increase the output voltage to 19V and if so how?

author: amyk
author_rank: Super Contributor
timestamp: January 21, 2024, 08:54:07 pm
content: You could just disconnect the V12 input, but if you want to keep the overvoltage protection you'll need a voltage divider that gives 12V to it at your desired output voltage. Beware of 16v capacitors on the 12v rail, and other components that might not withstand 19v.

author: avitsur
author_rank: Contributor
timestamp: January 22, 2024, 01:47:35 pm
content: Quote from: amyk on January 21, 2024, 08:54:07 pmI'm trying to understand - I have to put a voltage divider from the former +12V (which is now supposed to be 19V) line to the gnd so that the V12 input will still be 12V, but what determines that the output will be +19V?
Keeping a usb connection alive with the Device removed - Page 1
Forum section: electronics / projects

author: johnplagis
author_rank: Newbie
timestamp: June 17, 2018, 06:12:20 am
content: Ok, this is a bit complicated. After reading the USB Specification Datasheet and searching for hours I found that in order to keep a USB Device alive you have to use Pull up resistors (either on D+ if it is highspeed or D- if is a low speed device). What I want to accompish is fake the host that my device is in Suspend mode, while basically switching device. (Let's say I have two identical devices and I want to switch them without the host understanding that this happened). Has anyone used anything similar?Thank you for your time

author: ataradov
author_rank: Super Contributor
timestamp: June 17, 2018, 07:11:46 am
content: It is practically impossible. You would have to transfer complete state of the device being unplugged to the other device. At the very least you will need to know the address that was assigned to the original device, since suspended device will go into the addressed state on wake-up.
Keeping specs of 18-bit DAC - Page 1
Forum section: electronics / projects

author: ezalys
author_rank: Frequent Contributor
timestamp: July 06, 2020, 01:11:35 am
content: Hey all,I'm interested in laying out a board with an 18-bit DAC on it. Besides careful power distribution, layout, grounding, and thermals, what other considerations should I make for preventing switching noise or other things from ruining the performance of the output? This thing will be in the same chassis (eurorack) as a raspberry pi-- so I'm very concerned about radiated EMI making its way into the output signal. I was thinking of using a board-level shield over the converter, and then running the output signal through the inside of the board up to the SMA connector. Is this a winning strategy?Best wishes,E

author: mawyatt
author_rank: Super Contributor
timestamp: July 06, 2020, 02:30:09 pm
content: We used the TI ISO1541 to isolate the data lines for a 16 bit ADC and DAC operating with the RPi. This allows a separate power supply with separate grounds for the ADC and DAC.Best,

author: Micke
author_rank: Regular Contributor
timestamp: July 07, 2020, 06:21:41 am
content: I did some quite similar recently, built an accurate ACV/DCV voltage source...D/A was 20-bit AD5791, controlled via SPI @15MHz by a dsPIC33 @128MHzMight be some inspiration!https://www.eevblog.com/forum/metrology/diy-acvdcv-calibrator-with-ad5791/I used a 4-layer board, stackup:Top: Signals and available space Ground planes (Digital and Analog)Inner1: +15VInner2: -15VBottom: Ground planes (Digital and Analog)The only connection between Digital and Analog ground is made on Bottom side of PCB, under the D/A converter. I opened up a rectangular area in the solder mask to be able to solder a wire between the two ground planes.Used lots of filtering with ferrites and decoupling on the supples, isolated SPI interface and dedicated ground planes.Important is to not place components or traces in "wrong" place, digital and analog traces and components must not be placed in same zone (on any layer). Good luck with your project!
Keithley 2002 schematic - Page 1
Forum section: electronics / projects

author: Charles.C
author_rank: Newbie
timestamp: January 20, 2013, 10:32:43 am
content: Dear members,Does any of you have a Keithley 2002 schematic?I need to check the current source for ohm measurement ( test 304.2,306.1,306,2 failed).Keithley publish a repair manual, but it seems they have gone through great lengths to obfuscate the circuit as much as possible.In the manual is lot of typo, some of them can be identified easily.I made a list of affected compoents accordind to repar manual. Bellow is the resultsPosition Repair Manual BoardU219 LT21000A LTZ1000AU225 N/A LT1097U231 MAX326CSE AD706U232 LN35DM MAX326U233 N/A AD705U254 74HC165D OP177U255 74HC165D AD707I would very much appreciate this.

author: smoothVTer
author_rank: Regular Contributor
timestamp: September 16, 2016, 06:45:03 pm
content: Just found this, I understand it was several years ago.Were you ever able to find the complete Keithley 2002 schematic?

author: TiN
author_rank: Super Contributor
timestamp: September 16, 2016, 07:31:17 pm
content: Why you need it? Any issue with your unit?2002 are in lot of things common to well-studied 2001, and I had reversed some bits of 2002 which were interesting to me.

author: smoothVTer
author_rank: Regular Contributor
timestamp: September 20, 2016, 03:35:41 pm
content: QuoteIn TiN's K2002 restoration post, it was noted that the sponge under a JFET diff pair was probably there to equalize the thermal profile across the PCB ... these pair of JFETs are in close proximity to a DC/DC converter module which ( I verified this on my own K2002 ) gets rather hot. I want to trash this sponge because it leaks goo over guarded PCB areas.I am looking for K2002 schematic because: (1) K2001 does not have this DC/DC converter. I want to know why the K2002 needs this additional +/- 12V rail and what device(s) use this +/-12V (2) I'm trying to resolve the thermal issue ostensibly caused by this DC/DC converter by possibly moving this hot module to outside the black case. I know, I know: blasphemy! Bad hacker. Depending on what devices use this rail it may not affect overall K2002 performance if the module is moved to an alternate location ... or ever perhaps elevated above the PCB by a centimeter.
Keithley 230 schemtic explanation - Page 1
Forum section: electronics / projects

author: derZockerMP
author_rank: Regular Contributor
timestamp: December 04, 2024, 12:34:43 pm
content: Can someone explain this sentence to me in the Keithley 230 voltage source service manual? In my opinion this OP is intended to compensate for the different HFE of the output BJTsThen someone can explain to me, that would be very nice
Keithley 2302/3/4/6 inexpensive 8-pin terminal block - Page 1
Forum section: electronics / projects

author: rastro
author_rank: Frequent Contributor
timestamp: September 28, 2016, 10:26:27 pm
content: I found some inexpensive 8-pin terminal blocks for Keithley Power supply 2303/4 & Battery simulator 2306/2.They do not have the screw attachments but still fit snugly to the instrument and only cost $1.00I seems the Keithley connectors are little more expensive.I picked these up at tayda electronics.http://www.taydaelectronics.com/connectors-sockets/terminal-blocks/pluggable/8-pin-female-plug-in-type-vertical-terminal-block-5mm-5esdv.htmlIt looks like digikey has a similar connector with screws for ~$3.00. I have not verified the fit on these.https://www.digikey.com/product-detail/en/amphenol-fci/20020002-H081B01LF/609-4225-ND/2509295-rastro
Keithley Low Level Handbook - New 7th Edition - Page 1
Forum section: electronics / projects

author: quarks
author_rank: Frequent Contributor
timestamp: February 15, 2014, 02:09:25 pm
content: in case you do not already know, Keithley just released the 7th Edition of the great highly recommended Low Level Measurements Handbook (245 pages)

author: dr.diesel
author_rank: Super Contributor
timestamp: February 15, 2014, 02:12:35 pm
content: Appears to be digital only, couldn't find a hardcopy.

author: Fsck
author_rank: Super Contributor
timestamp: February 15, 2014, 11:06:28 pm
content: thanks!