hybridfree/eevblog-posts huggingface dataset:
FNG checking in... - Page 1
Forum section: electronics / beginners

author: terabyte
author_rank: Contributor
timestamp: August 24, 2010, 02:16:17 am
content: So I messed with simple electronics and R\C stuff as a kid, then computers took over and I made a career out of it. (Network Engineer\Administrator)On the hobby front I was into cars as a younger adult and then that was replaced by racing motorcycles.Well the spine has a few bulged discs and I am trying to take it a little easier. So I'm going back to an old passion.So far I have been following advise on here and I've got;Fluke 87 III for less than $100 on eBay.Tek 50MHZ for about $120 o"Custom" bench\stationMastech PSUfew more things...Here is the beginnings of this FNGs setup. I will post some more pics as I progress...and the other passionhere is the "other" lab;

author: DJPhil
author_rank: Frequent Contributor
timestamp: August 24, 2010, 07:32:47 am
content: Quote from: terabyte on August 24, 2010, 02:16:17 amLooks like you're off to a great start! I wish I still had that much storage space, it fills up so quickly.We were all FNGs at some point, no worries.Nice windscreen sticker on that bike.Love the garage too, wish I had a welder sometimes. You've got an oven in the garage too! For baking headers?

author: orbiter
author_rank: Frequent Contributor
timestamp: August 24, 2010, 02:06:59 pm
content: Beginnings of a great lab you got there mate. I recognise that book on the side there too.. 'Make Electronics?' I just got that myselfIt's a great book.I'm a bike fan also. Used to race a few years back but injury has caught up with me now. My brother went one stage further than the track and moved on to to do the Isle of Man TT race for 7 years, and is in fact going over to the Isle of Man again tomorrow for the Manx GPHere's a pic of his latest road toy... In fact it's not his latest as he's just bought a new Anniversary BMW R1200 GS Adventure tooAs you can tell by the chicken strips on the rear tyre, it's not run-in yetOnly 30 miles on the clock.RegardsJohn

author: djsb
author_rank: Super Contributor
timestamp: August 24, 2010, 04:10:13 pm
content: Another biker here. I own two German MZ's, an RT125 and a Skorpion travellerhttp://t1.gstatic.com/images?q=tbn:ANd9GcRLa8GP_WapTJfdxByhjdDX9Rhg8EmZvm5p5vCViSygS-e4wqQ&t=1&usg=__zhGmODK_gI7h2lxUf0YJkjA_MZM=Don't have a workshop so I do all my work outside my window.Used to live in Salford, near Manchester and I miss my rides out to the lovely north Wales countryside. Too far now I live in London.David.
FNIRSI USB tester - A budget 5-digit BT voltmeter? - Page 1
Forum section: electronics / beginners

author: Cliff Matthews
author_rank: Unknown
timestamp: February 16, 2023, 01:59:27 pm
content: Could this new productreallyhave such a high-resolution ADC as its 6-digit display would seem to indicate? I suppose if the BT protocol was hacked and it was powered externally by a variable 5 to 15 volt reference, one could double its functionality as a quasi 10,000 count voltmeter and portable logging device (without ever opening it...)DiodeGoneWild opened one at about the 9 minute mark (maybe the ADC is the SSOIC-10 above the current shunt?)

author: ledtester
author_rank: Super Contributor
timestamp: February 16, 2023, 03:39:23 pm
content: TheHWCave did a video on using a USB tester (a TC66) that employs an TI INA226 as a 5.5 digit DC meter:Using the TC66 USB tester as a $30 5½ digit precision multi-meter -- TheHWCavehttps://youtu.be/iZ5JjA6DoZgAnd his teardown/review of the TC66:Ruideng TC66 / TC66C USB Type-C Tester - Way too good for just USB!https://youtu.be/rOlhibDUJgs

author: Gyro
author_rank: Super Contributor
timestamp: February 16, 2023, 07:30:33 pm
content: That really does seem like an excessive number of decimal places for a simple USB tester. I think I would have gone for a faster update rate instead.Edit: It does look like it might have potential for other uses though.

author: Cliff Matthews
author_rank: Unknown
timestamp: February 16, 2023, 10:39:48 pm
content: Quote from: ledtester on February 16, 2023, 03:39:23 pmThanks! That TC66C seems like it would also work, but I overlooked negative voltages (it would take some work!)TheHWCave provided a good reference:https://sigrok.org/wiki/RDTech_TC66CI think it would require an isolated outboard front-end with a stable 15v reference, along with a summing amp capable of a linear 20v swing. A basic BT app would offset displayed readings as -10.0v=5.0v, 0.0v=15.0v, and +10.0v=25.0v together with a 10x and 100x decimal shift for good measure, pardon the humourI'd bet Joe Smith could make this look easy, like a Sunday walk in the park with his dog.

author: thm_w
author_rank: Super Contributor
timestamp: February 17, 2023, 12:04:19 am
content: 24V / 0.0001V = 240,000. So it would seem to be an 18-bit+ ADC.Could be MAX11212, or some China clone equivalent. Or they are oversampling on a 12/14-bit converter.Look at the internal reference spec for these, they are OK, but not great compared to an external reference.

author: Vovk_Z
author_rank: Super Contributor
timestamp: February 17, 2023, 08:33:01 pm
content: In theory it may have 16-bit or less ADC and a good wiring design and fast averaging.
Foldback Current Limiting - an example - Page 1
Forum section: electronics / beginners

author: iMo
author_rank: Super Contributor
timestamp: June 01, 2019, 04:07:37 pm
content: Here is a small simulation with calculation of the resistors for a Foldback Current Limiting.Normally the current limiting with LM723 (or any other PSU with same current limiting wiring) works such the current flowing through the shorted output is aprox.I_limit = 0.7V/R_shuntWith the Foldback Current Limiting the current during short is much lower, call it I_short.Thus we have I_limit and I_short. After the output current approaches I_limit, it starts to drop down to I_short.In the below example the I_short is aprox. 5x smaller than the I_limit.Below is, as an example, a simulation with an LM723 and the calculation.To find the right values is not straightforward, however.The Rshunt is a much higher value as you would expect, and the both currents depend on the Rshunt value and R4/R5 ratio as well.Excel sheet with the goal seeker is something which may help.The simulation shows the calculation fits pretty well, with larger deviations when k < 0.8 ..Code:I_limit I_shortCalc: 41mA 8.5mASim: 39mA 8.7mAMore on how it works here:http://www.eeeguide.com/foldback-current-limiting/

author: ledtester
author_rank: Super Contributor
timestamp: June 01, 2019, 10:08:39 pm
content: FWIW, this lecture on the topic might also be helpful:
Fontaine MC4020c schematic - Page 1
Forum section: electronics / beginners

author: shobo
author_rank: Regular Contributor
timestamp: January 28, 2018, 01:03:52 am
content: Does anyone nave a schematic for a FONTAINE MC4020C power supply?i could only fond IT on a ham radio forum crom france where the guys shared IT via email and the registration question is in french and i dont understand IT.Link to the forum page:http://www.retro-forum.com/viewtopic.phpPic of the supply(not the one in the pictur? but identical)Sent from my VFD 1100 using Tapatalk

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 28, 2018, 04:26:03 am
content: I have the same PSU, that is on my shelf, waiting for repair.The schematics would certainly be useful. I will see what I can do with the french site, but although the post is old.

author: shobo
author_rank: Regular Contributor
timestamp: January 28, 2018, 11:33:18 am
content: Quote from: JacquesBBB on January 28, 2018, 04:26:03 amI managed to register on the forum and posted there and even searched one of the emails on facebook and contacted the dude.hopefully i'll get a response.

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 28, 2018, 02:29:57 pm
content: I checked mine. Its exactly the same outfit, but model MC1050 should be 10V 5 A.If you get the schematics of the MC4020, I will be interested.

author: shobo
author_rank: Regular Contributor
timestamp: January 29, 2018, 12:46:55 pm
content: made contact with one of the guy from that forum and is gonna send me the manual on Friday (he said it's a big file so manual is my best bet),so...FUCK YEAH!

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 29, 2018, 04:36:48 pm
content: Fine,I checked my MC1050. The voltage is fine but the current limit is erratic unless it has heated fo a while. So I will have to do some repair.A the case is exactly the same as yours, I imagine the inside will be very close.

author: shobo
author_rank: Regular Contributor
timestamp: January 29, 2018, 07:15:33 pm
content: Jacques bere IT is!http://cloud.tapatalk.com/s/5a6f72aee8ff0/Fontaine_MC4020_alim-labo.pdfSent from my VFD 1100 using Tapatalk

author: JacquesBBB
author_rank: Frequent Contributor
timestamp: January 29, 2018, 11:22:43 pm
content: Thanks.This will push me to restore my MC1050 to its full state. It impressive to see that this 50 yr old device is still working. I checked some electrolytic. They were all fine.

author: shobo
author_rank: Regular Contributor
timestamp: January 30, 2018, 10:39:55 am
content: My multimeter doesn't have capacitance to check them but it seems like it's in good working order.i guess that since it doesnt look swolen or leaky or fizzes it's ok.
Footprint without datasheet - Page 1
Forum section: electronics / beginners

author: hitech95
author_rank: Regular Contributor
timestamp: June 02, 2019, 08:44:41 pm
content: Hi,I have to create the footprint of a USB connctor.https://it.aliexpress.com/item/1pcs-USB-3-0-jack-fit-for-Acer-Chromebook-C720-C720-2848-CB5-571-C9DH-ZRF/32785466540.html?spm=a2g0s.8937460.0.0.398b2e0exsoqftUnfortunatly the supplier don't have the Datasheet and it's a custom part made for Acer by someone.I have the photos and a PCB with the same connector installed.How can I create a footprint for it?Does you have any suggestions?Have a nice day,hitech95

author: MarkF
author_rank: Super Contributor
timestamp: June 03, 2019, 12:26:28 am
content: You have the actual part.Measure it.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 03, 2019, 12:30:21 am
content: Got a micrometer or at least vernier calipers? Or an optical measuring table, but those are probably too special..I would suggest copying what's on the existing board. Desolder and clean the footprint, then measure it with whatever instruments and gauges are appropriate.That may be more difficult to do than expected. Perhaps you should consider a new, reputable brand connector that comes with datasheet? Since you're building new anyway (so it seems), there doesn't seem to be any point at all in using an exact match to the original.Tim

author: wraper
author_rank: Unknown
timestamp: June 03, 2019, 12:35:20 am
content: Why would you need a footprint for this particular part? As said before, measure it. However it would be much smarter to choose part which has the same dimensions as a part which has a proper drawing available. Even if you want to use some cheap crap from Aliexpress anyway.

author: hitech95
author_rank: Regular Contributor
timestamp: June 03, 2019, 11:32:54 am
content: Quote from: MarkF on June 03, 2019, 12:26:28 amI got a draft of the dimensions from the connector, I thought someone had a trick to be sure of the size and pads placing.The connector it's soldered to my notebook motherboard!Quote from: wraper on June 03, 2019, 12:35:20 amQuote from: T3sl4co1l on June 03, 2019, 12:30:21 amIt's not why it's cheaper but due to the fact that is aligned with my notebook chassi!I've looked for new parts but this connector is placed at the same height of the PCB and its perfectly aligned with the hole in the chassi. (The pcb is cutted and the connector fits inside the "hole")Quote from: T3sl4co1l on June 03, 2019, 12:30:21 amYup i've got the draft but I would to be sure of the actual dimension ... i'm also waiting for the part to arrive from china...Quote from: T3sl4co1l on June 03, 2019, 12:30:21 amPart of the problem is actually this, the connector is soldered to the motherboard of the PC I use each day and my desoldering skills are not that good. (Expecially with plastic connectors)BTW, I'm working on this:https://www.eevblog.com/forum/projects/adding-usb-type-c-with-pd-(tps65987d)-to-a-chromebook-advices-for-usb3-pcie/
footprints and dimensions  - Page 1
Forum section: electronics / beginners

author: manubali
author_rank: Contributor
timestamp: May 27, 2017, 03:45:13 am
content: hi, recently i started designing circuits and while creating footprints i have many doubts. i will list them here and maybe someone can help me.1: while checking lead diameter why there are dimensions like :3X 0.55 (.022)0.46 (.018)why there is 3x in front of them?what does M B A M stands for? (see image)2: how can i calculate hole size and pad diameter?3: where can i get 3d models?

author: mdszy
author_rank: Unknown
timestamp: May 27, 2017, 03:52:56 am
content: Your image is fubar, do you have a datasheet with pad dimensions you're working from?

author: manubali
author_rank: Contributor
timestamp: May 27, 2017, 03:57:54 am
content: Quote from: mdszy on May 27, 2017, 03:52:56 amyes i have datasheet for IRF540NPBF mOSFET

author: mdszy
author_rank: Unknown
timestamp: May 27, 2017, 04:06:39 am
content: Okay so, the datasheet says"Dimensions are shown in millimeters (inches)" which means the number in parentheses is inches, the number without parentheses is mm.3x means that there are 3 pins and the indicated dimension can be anywhere from 0.55mm to 0.46mm.I have no clue what the MBAM marker thing stands for, sorry.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: May 27, 2017, 04:26:41 am
content: MDSZY is right, and the M in the circle is a geometric tolerancing symbol. Here are some explanations.http://www.cobanengineering.com/GeometricDimensioningAndTolerancing/GeometricTolerancingAndSymbols.asp

author: manubali
author_rank: Contributor
timestamp: May 28, 2017, 01:57:26 am
content: Quote from: mdszy on May 27, 2017, 04:06:39 amThanks, can you also tell me how to calculate hole sizes and pad diameter?

author: Twoflower
author_rank: Frequent Contributor
timestamp: May 28, 2017, 10:40:46 am
content: Here's the package specification from Vishay for the TO-220AB:https://www.vishay.com/docs/71195/to220ab.pdfThe pins are build up a rectangle with the dimensions b x C = 1.73mm x 0.61mm. The hole diameter should be bigger than: d = sqrt(a^2 + b^2). But be careful. If you specify the drill diameter exact to that number you call for trouble. As the plating (double sided PCB) will reduce the effective diameter. See alsohttps://www.pcb-3d.com/knowledge-base/pth-dimensions/About the question for the 3D model: The IRF540NPBF uses a normal TO-220AB housing. I would say you'll find plenty of models out there (hint: look at the URL above)
For 802.11n, is it possible to have MIMO on single antenna? - Page 1
Forum section: electronics / beginners

author: sam1275
author_rank: Frequent Contributor
timestamp: May 08, 2017, 06:16:31 am
content: Hello.I'm traveling to Asia and using one of their fiber ISP, they give me a modem combo that have wireless router built in. It have a RTL8192ER chipset for wireless, which is 2x2 MIMO, but there's only one antenna on the PCB. I do get 300Mbps indication on some devices, however Wikipedia says it's not possible to have 2 streams on a single antenna:https://en.wikipedia.org/wiki/IEEE_802.11n-2009#Number_of_antennasSo is it only capable of 1x1:1, despite of the 300Mbps indicator on some wireless clients?Thanks.

author: Chalcogenide
author_rank: Regular Contributor
timestamp: May 08, 2017, 07:47:42 am
content: Can you provide a pic of the PCB? It may be possible that it has a PCB antenna and a chip antenna, which could be mistaken for a simple passive.

author: sam1275
author_rank: Frequent Contributor
timestamp: May 08, 2017, 02:50:40 pm
content: Photos here:I just noticed the PCB antenna which I missed before.Thank you.
for atteintion of alan W2AEW Fast pulse generator - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 04, 2013, 05:39:00 pm
content: Hi Alan finished the fast pulse generator, you can see it's ringing ok on the top of the trace and a small ringing on the bottom start edge, I'm going to build the other part tomorrow for inductance and capacitance, tried it on coax, but mine has a 4: 1 balun in it, so it reflected pretty much as this only larger, I'm running it at 3.5ish volts, which seems to be most happiest at, it's a brilliant edition to the ham shack. there is one thing I need to ask ,my scope measures in micro seconds , not nano, seconds, and I don't know the calculation difference between the twoThanksPaul

author: SeanB
author_rank: Super Contributor
timestamp: May 04, 2013, 05:52:05 pm
content: 1000nS is 1 microsecond.

author: Monkeh
author_rank: Super Contributor
timestamp: May 04, 2013, 06:31:11 pm
content: Quote from: SeanB on May 04, 2013, 05:52:05 pm1000 nanosiemens is 1 microsecond?

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 04, 2013, 06:35:18 pm
content: Thank you

author: w2aew
author_rank: Super Contributor
timestamp: May 04, 2013, 06:56:49 pm
content: Good job, Paul. Looks like you've got your answer. Multiply microseconds to get nanoseconds.

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 04, 2013, 07:57:02 pm
content: Quote from: w2aew on May 04, 2013, 06:56:49 pmThanks Alan , I've made a start on the inductance capacitance part now , what's next, I'm enjoying the training, especially as I can use this equipment in the shack , perhaps a variable audio filter would be useful.Paul

author: w2aew
author_rank: Super Contributor
timestamp: May 05, 2013, 01:20:26 am
content: Quote from: M0BSW on May 04, 2013, 07:57:02 pmHave you checked out my D104 mic preamp / EQ video? It's a decent general purpose mic preamp and active bass/treble control circuit. Good for simple mic equalization for your rig.I've got a few more ideas for the fast-edge pulser, maybe I'll have something to share in a few weeks.

author: M0BSW
author_rank: Frequent Contributor
timestamp: May 05, 2013, 07:05:20 am
content: Hi Alan , I'm gathering the parts now for your audio amp EQ, that looks like a nice project, and looking forward to more instalments on the fast edge.Thanks for replying.Paul M0BSW
For Beginners And People Like Occasional Teardowns - Page 1
Forum section: electronics / beginners

author: PStevenson
author_rank: Regular Contributor
timestamp: March 01, 2013, 08:48:21 am
content: Please come and like my Facebook page - go onhttp://www.facebook.com/StripboardLayouts

author: FenderBender
author_rank: Super Contributor
timestamp: March 01, 2013, 10:58:52 pm
content: Interesting!! I'm not so sure if I like the facebook part of it though. Good for commenting, but might as well just post them here. Or link to a flickr album here or something.
For hobbyists, why buy 1N4001 diodes when you can buy a 1N4007? - Page 1
Forum section: electronics / beginners

author: jolshefsky
author_rank: Regular Contributor
timestamp: April 15, 2014, 05:11:41 pm
content: This is something that has puzzled me for a long time. Why would anyone these days buy a 1N4001 diode and not a 1N4007?Background information: the 1N400x series is a basic silicon diode useful for things like power rectification or input protection for up to 1A current. The 1N4001 has a breakdown voltage of 50 volts. 1N4002: 100V, 1N4003: 200V, 1N4004: 400V, 1N4005: 600V, 1N4006: 800V, and 1N4007: 1000V. The other electrical characteristics are the same.So if I were shopping for diodes, if I was doing some kind of low-voltage supply, I might pick the 1N4001. But then if you're a hobbyist, you might want to rectify mains voltage someday, so you'd want 600V. Or maybe you've got a use for a 1000V breakdown. If you're stocking your home supply, why not just buy 1N4007 and use them for everything?The only thing I can think of is the price. But looking at DigiKey, the price for a single Fairchild 1N4001 is US$0.18, and for 1,000, it's US$0.03646 each. The 1N4007: US$0.18 for 1, US$0.03646 for 1,000.I'm stumped!

author: Richard Crowley
author_rank: Super Contributor
timestamp: April 15, 2014, 05:22:11 pm
content: I had heard (but cannot find the reference now to confirm) that 1N4005 and up are made on a different (high-voltage) semiconductor fab process which has different HF and capacitance characteristics than the lower-voltage 1N400x series. Of course, if you are using these only for bog-simple, ordinary mains-frequency linear power supplies, it probably doesn't make any difference.

author: Zero999
author_rank: Super Contributor
timestamp: April 15, 2014, 06:48:12 pm
content: The 1N4005 and up have a lower capacitance.

author: David Hess
author_rank: Super Contributor
timestamp: April 15, 2014, 07:09:51 pm
content: Quote from: Richard Crowley on April 15, 2014, 05:22:11 pmHigh voltage rectifiers are often or always fabricated using a PIN structure which also makes them useful as voltage variable capacitance, PIN, and snap-off diodes but you would have to qualify them yourself and they tend to have high capacitance because of large junction size.The higher voltage diodes also have higher forward voltage drops and usually slower recovery times but those should not matter in the applications that the 1N400x series are used in.As to why the lower voltage ones even exist, sometimes a low and specified breakdown voltage is desired so they can do double duty preventing over-voltage but in this case, I suspect it is just because they can be sold and someone will buy them. I only keep 1N4004s or higher available for general repair work.
For testing spec OP AMP, can i use this circuit ? - Page 1
Forum section: electronics / beginners

author: ammjy
author_rank: Regular Contributor
timestamp: March 10, 2017, 08:26:38 am
content: Hello !i don't know about OP AMP well. but, for my project i buyed low noise op amp OP37G.but, i don't know it's fake or not fake. so i want check my op amp via input bias current.Please, see screenshot picture. can i use this circuit for checking spec OP37G ?i have EEVBlog ucurrent.in datasheet, input bias current is typical ±15 nA, Maximum ±80 nA.and checking via input bias current is good method ?i want check via offset voltage. but, my oscilloscope resolution is just 2mV with Bandwith limit. i don't have idea.\Please, let me know. Please, i need help.

author: Zero999
author_rank: Super Contributor
timestamp: March 10, 2017, 08:47:24 am
content: You should use higher resistor values than that to measure the bias current.Why are you using an oscilloscope to measure the offset current? It's the wrong tool for the job. You need a volt meter to measure DC voltages.

author: ammjy
author_rank: Regular Contributor
timestamp: March 10, 2017, 08:54:02 am
content: Thanks you.i mistake wrote, Sorry. i always in tension.....i will use my multimeter and ucurrent. but, multimeter can't measure nV range. ucurrent is for currunt measure.without any input, just with x1000 feedback circuit, can i measure offset voltage ? +/- 15~80 nV ?

author: danadak
author_rank: Super Contributor
timestamp: March 10, 2017, 12:40:05 pm
content: From one of the gurus of our time -https://www.ti.com/ww/en/bobpease/assets/www-national-com_rap.pdfPick the article "What's All This Femtoampere Stuff, Anyhow?" and "What's All This Teflon Stuff, Anyhow?"Regards, Dana.

author: b_force
author_rank: Super Contributor
timestamp: March 10, 2017, 02:41:23 pm
content: Quote from: Hero999 on March 10, 2017, 08:47:24 amThat really depends on the type of scope and multimeter.I know enough scopes that are much more accurate than some multimeters.

author: Zero999
author_rank: Super Contributor
timestamp: March 10, 2017, 03:00:17 pm
content: Quote from: ammjy on March 10, 2017, 08:54:02 amIt depends on the accuracy of the multimeter. You may need to increase the gain further.Quote from: b_force on March 10, 2017, 02:41:23 pmThey must be pretty poor multimeterss.

author: ammjy
author_rank: Regular Contributor
timestamp: March 10, 2017, 04:13:51 pm
content: Quote from: danadak on March 10, 2017, 12:40:05 pmThanks you teach me.I'll not forgot your help. Thanks !

author: ammjy
author_rank: Regular Contributor
timestamp: March 10, 2017, 04:15:52 pm
content: Quote from: Hero999 on March 10, 2017, 03:00:17 pmThanks you, your advice.i'll not forgot your help ! ill try !

author: ammjy
author_rank: Regular Contributor
timestamp: March 10, 2017, 04:17:33 pm
content: Quote from: b_force on March 10, 2017, 02:41:23 pmThanks you comment !today, i studied via you.
For the life of me I cant find Eyelet solder tags, am I using the wrong name? - Page 1
Forum section: electronics / beginners

author: peps1
author_rank: Regular Contributor
timestamp: March 24, 2022, 04:21:21 am
content: I have spent at least 6 hours now looking for what I would call Eyelet solder tags here in the UK or on Aliextrpess (as I need about 1000 of the blighters).But for some reason the only ones I have come across have been on two Swiss sitesI'm starting to think I'm looking for the wrong thing, is there another name for these guys?https://www.vogtshop.ch/index.cfm?content=productData&Language=1&TreeID=9F6BEEE5-85EF-483B-BE0C-658BC6F0A78E&sId=2B189379-7445-4C16-892C-0EE38F5B6DB4For the sake of my diminishing sanity from hours scrolling through the usual suspects like Mouser, Digikey Farnell, AliExpress and smaller electronics stores in the UK. It's time to throw myself at the mercy of this forum and beg for help!Please tell me I'm just using the wrong search term, and what I really need to be looking for is the ubiquitous "M2.5 PCB mount ferrule grounding terminal"

author: golden_labels
author_rank: Super Contributor
timestamp: March 24, 2022, 05:25:42 am
content: On DigiKey:Terminals → Solder Lug Connectors. Is that what you’re seeking?

author: peps1
author_rank: Regular Contributor
timestamp: March 24, 2022, 06:19:59 am
content: Unfortnetlyt not, I need that, but with the eyelet that goes into the board....but very near!

author: jpanhalt
author_rank: Super Contributor
timestamp: March 24, 2022, 09:19:08 am
content: Does this work for you:https://www.keyelco.com/category.cfm/Terminals-Lug-Lockwasher/Solder-Terminal-Lugs/p/509/id/514/c_id/770(#1204)? The search term is swage mount solder lug.The eyelet appears to be square. There is also the #680 , which has a tab that can go into a plated through hole.

author: tooki
author_rank: Super Contributor
timestamp: March 24, 2022, 12:20:36 pm
content: Try searching for “rivet solder terminal” and “rivet solder lug”, too, since many vendors don’t use the term “swage”.I bet these were far easier to find many decades ago, when terminal strips were common. These days one rarely sees those, so it’s not surprising the terminals for them aren’t made as commonly, either.peps1, what’s the intended application? Maybe there’s a better solution overall.

author: PA0PBZ
author_rank: Super Contributor
timestamp: March 24, 2022, 02:54:17 pm
content: Not sure how many you need but I found this where you can cut off one end:https://www.ebay.com/itm/133664896463

author: peps1
author_rank: Regular Contributor
timestamp: March 24, 2022, 05:43:59 pm
content: Quote from: tooki on March 24, 2022, 12:20:36 pmUnfortunately, it's for vintage equipment restoration and recreation, so limited on how much wiggle room have to deviate.Though, I do wonder why the Swiss seem to still make ;Dl

author: tooki
author_rank: Super Contributor
timestamp: March 25, 2022, 12:43:32 pm
content: Quote from: peps1 on March 24, 2022, 05:43:59 pmWell, there clearlyisstill a small market for them, as you’re evidence of!FWIW, Vogt products are of excellent quality.
For the love of god, someone show me officially how a USB 1.1 device is wired. - Page 1
Forum section: electronics / beginners

author: K3mHtH
author_rank: Regular Contributor
timestamp: November 05, 2024, 02:02:28 am
content: Looking for an official document or datasheet that shows exactly how USB 1.1 wants a DEVICE connector to be wired internally. I've read at least 5 different answers online:1: Leave Shield Disconnected, it's already grounded at the host.2: Connect Shield to Ground.3. Connect Shield to Ground via 1M and 4.7nF RC.4. Connect Shield to Ground via inductor/ferrite.5. Connect Shield to Ground via 1M and many capacitors.I've only found this document (http://esd.cs.ucr.edu/webres/usb11.pdf) and the only thing it says is:Quote

author: ataradov
author_rank: Super Contributor
timestamp: November 05, 2024, 03:46:12 am
content: There is no "official" method. The spec is a copout that says nothing useful. The easiest thing you can do is not overthink it and just connect everything to the ground.You may argue for not connecting it on the device side, but all the resistors and capacitors are pure voodoo nonsense.

author: ArdWar
author_rank: Frequent Contributor
timestamp: November 05, 2024, 04:04:17 am
content: There may be a case to not connect the shield if your device may be powered by class I PSU separate from its host, but most devices don't do that and you shouldn't design yours that way either.

author: u666sa
author_rank: Frequent Contributor
timestamp: November 05, 2024, 07:09:05 am
content: Quote from: K3mHtH on November 05, 2024, 02:02:28 amSpecification calls for maximum of 5 meter length. As you know, often with long USB cables bad things happen. No connection. Intermitten connection. Decreased bandwidth. At the minimum you should connect shield to ground. Other methods could be useful as well. It depends how your cable acts with 3 to 5 meter length.
For what specific function the capacitors and inductors are used exactly? - Page 1
Forum section: electronics / beginners

author: electrowhiz
author_rank: Contributor
timestamp: May 16, 2018, 07:29:19 am
content: The three basic components are resistors,capacitors, inductors . Resistors are used to limit the current. Capacitors and inductors are used to store the energy in terms of electric and magnetic field. Where exactly these properties of capacitors and inductors are used?

author: BNElecEng
author_rank: Regular Contributor
timestamp: May 16, 2018, 07:37:40 am
content: Capacitors and inductors have many uses. It would be very difficult to list them all here. One example is as a filter on the output of a switch mode power supply. Another example is their use in opamp circuits to create a differentiator or integrator function.I recommend you look up these circuits and you will learn a lot.
Forced discharge tests for D batteries - Page 1
Forum section: electronics / beginners

author: nml
author_rank: Newbie
timestamp: June 25, 2014, 08:47:24 pm
content: I am currently on a project testing used D batteries and I need to gather data about their lifespan. I would like to run some forced discharge tests and record the data. I have a dc power supply available. Does it make sense to put a battery in series with the power supply with reversed polarity to pull a certain current from the batteries (attached figure)?Thanks!

author: katzohki
author_rank: Frequent Contributor
timestamp: June 25, 2014, 09:17:52 pm
content: Calculate the rate of discharge you want (or make it up). Use that to calculate the current and choose a resistor based off the voltage (1.5V) and current you have chosen. Use that to discharge it.Or just short the thing. That will discharge it "just fine".

author: AmmoJammo
author_rank: Frequent Contributor
timestamp: June 25, 2014, 09:59:15 pm
content: in for pics of when it catches on fire!

author: nml
author_rank: Newbie
timestamp: June 25, 2014, 10:06:05 pm
content: I'm trying to avoid fire...Any suggestions would be helpful!

author: denelec
author_rank: Regular Contributor
timestamp: June 25, 2014, 10:31:34 pm
content: The capacity of a battery will vary greatly with the discharge current.The greater the current, the lower the capacity in ampere-hour.See the datasheet of an Energizer D battery:http://data.energizer.com/PDFs/E95.pdfYou must test the batteries with the same current you will use them.I would use a resistance for the discharge test. Use a proper wattage resistor; P=V^2/R

author: vk6zgo
author_rank: Super Contributor
timestamp: June 26, 2014, 07:29:37 am
content: Quote from: nml on June 25, 2014, 08:47:24 pmDon't do this!The power supply will cook your battery & you won't get any sensible results.It might not be very good for your supply,either.I had a home made supply with every sort of protection except reverse polarity.I had used it to charge a 12v Lead acid battery many times,but this time I slipped up & reversed the battery connections.Bang!--very expensive regulator chip gone!The price of this chip went from $14 to $70 in the time between fitting the first one & needing to replace it.I'm a tightwad,so it was a matter of a quick re-design to use a cheap generic regulator.Not as much protection,but nearly as cheap as a fuse!
Form leads of TO-92 transistors to look like the cut-tape ones.. - Page 1
Forum section: electronics / beginners

author: belzrebuth
author_rank: Frequent Contributor
timestamp: August 20, 2018, 04:17:25 pm
content: Hi,I wonder if there is any tool or method to form the leads of bulk packaged transistors (straight) to look like those that are tape reel packaged (bent)..I can get somewhat close using flat nose pliers but it takes a bit of time..

author: darrellg
author_rank: Unknown
timestamp: August 20, 2018, 05:12:02 pm
content: Excelta 500-92-US Lead Forming Pliers
Formal package name for a QFN40 break out board ? - Page 1
Forum section: electronics / beginners

author: onesixright
author_rank: Frequent Contributor
timestamp: April 08, 2017, 09:53:32 pm
content: Hey Guys,Is there aformal(package) name for a adapter / breakout board with those half round holes on the sides when you can stick a (eg.) QFN40 on?I'm a designing a small PCB for a breakout (for a similar chip), but i have not a clue how to deal with this type of footprint.Is it 2.54mm pitch? I'm also not sure about the exact dimensionsI couldn't find anything in the datasheet - this case is a NXP JN5168-001-M00.I dont have the IC's yet (otherwise can i can measure it myself).Many thanks!

author: ataradov
author_rank: Super Contributor
timestamp: April 08, 2017, 10:39:39 pm
content: Half round holes are called castellated vias, and there is no standard size, you will have to get documentation for your specific device.

author: helius
author_rank: Super Contributor
timestamp: April 08, 2017, 10:40:47 pm
content: Those are called castellated pads. They are most commonly used for small radio or FPGA modules, where the user can either solder wires individually to each pad, or solder the whole module down to a larger PCB. The pad spacing is designed to be the same as protoboard/veroboard, typically 0.100". The idea that they are for mounting QFNs to is wrong.There is no JEDEC package name for it because it's not a package!

author: ataradov
author_rank: Super Contributor
timestamp: April 08, 2017, 10:45:11 pm
content: And the datasheet for the module has both drawings of the PCB landing pattern and module dimensions. Those things are spaced 1.27 mm apart.

author: onesixright
author_rank: Frequent Contributor
timestamp: April 09, 2017, 06:02:12 am
content: Thank you both!I checked the ds at the back of the document, where it often isApprently they detailed the outline drawing perfectly (page 10)For others have a look here:https://learn.sparkfun.com/tutorials/how-to-solder---castellated-mounting-holes
Formulae's - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 02, 2013, 06:43:16 pm
content: I've been trying to remember formulae's, I think I've forgotten one : V EA R P(w) T(s) I'm sure there's another popular one I've forgottenIf so can some one remind me of it, .Paul

author: Falcon69
author_rank: Super Contributor
timestamp: April 02, 2013, 06:44:15 pm
content: V=IR

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 02, 2013, 06:47:58 pm
content: Quote from: Falcon69 on April 02, 2013, 06:44:15 pmIsn't that the same as V=AR volts =Amps/resistance, where as I current and A amps are the same ,No thinking about it in electricity there all different if I remember correct.

author: 8086
author_rank: Super Contributor
timestamp: April 02, 2013, 07:00:58 pm
content: Don't use A for amps in equations, use I.Current (I) is measured in Amps (A).So yes, essentially the same. But better to use I rather than A.

author: Falcon69
author_rank: Super Contributor
timestamp: April 02, 2013, 07:03:18 pm
content: taken from my engineering book...V=W/Q (W is Work Done (Joules), Q=charge (columb))G=1/R (G is Conductance)R=pL/A (p=Resistivity of material (ohm/mm or ohm/in), A=Cross Sectional Area (m2or in2), L=Length (m or in))P=IV=I2R=V2/RI=Q/t (t=time (sec))There's LOTS more, but I think those are the basics.

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 02, 2013, 07:05:27 pm
content: Quote from: Falcon69 on April 02, 2013, 07:03:18 pmThanks Falcon, I'd clearly forgotten them computer are to easy, the older I get ,the more I want exercise the brain

author: Falcon69
author_rank: Super Contributor
timestamp: April 02, 2013, 07:06:19 pm
content: A simple search on google will give good ones also. This sitehttp://www.rapidtables.com/electric/Is a good source of basic ones.

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: April 02, 2013, 07:25:46 pm
content: P=IV is probably the one you felt like you were missing; it's the normal companion to V=IR.

author: Falcon69
author_rank: Super Contributor
timestamp: April 02, 2013, 07:30:35 pm
content: This is really handy to print off and keep around.

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 02, 2013, 07:45:56 pm
content: Quote from: Galaxyrise on April 02, 2013, 07:25:46 pm,Yes that's the one ,soon as I read your post I remembered , thank you

author: M0BSW
author_rank: Frequent Contributor
timestamp: April 02, 2013, 07:46:55 pm
content: Quote from: Falcon69 on April 02, 2013, 07:30:35 pmGreat I've run a copy off thank you

author: Galaxyrise
author_rank: Frequent Contributor
timestamp: April 02, 2013, 08:29:40 pm
content: Quote from: M0BSW on April 02, 2013, 06:47:58 pmV = IR means Voltage = Current TIMES Resistance. "Volts = Amps/Resistance" would mean Voltage = Current DIVIDED BY Resistance. Careful thereAlso, if you're sticking with units, it's Volts = Amps * Ohms.
forum problems when posting/editing - Page 1
Forum section: electronics / beginners

author: Anthocyanina
author_rank: Frequent Contributor
timestamp: May 07, 2021, 07:22:33 pm
content: Is anyone else having this issue? I haven't been able to consistently post/edit my posts lately. i get this error a lot. I've already tried on different computers and on different networks and i get this same error

author: RoGeorge
author_rank: Super Contributor
timestamp: May 07, 2021, 07:34:55 pm
content: Happened to me, too, a couple of times this week while trying to a add topic to ignore. Not yet while posting/editing. The error goes away after refresh and a second try.Better post the errors here, or else the admins might not notice the topic:https://www.eevblog.com/forum/chat/website-error-reports/

author: Anthocyanina
author_rank: Frequent Contributor
timestamp: May 07, 2021, 07:46:43 pm
content: Thank you! i didn't know about that topic, i'll post it there too
Forward Bias on a P-N Junction? - Page 1
Forum section: electronics / beginners

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: February 16, 2014, 08:06:52 pm
content: When one forward biases a p-n junction into conduction, does the applied voltage overcome the diffusion or electrical potential at the junction interface?

author: hamster_nz
author_rank: Super Contributor
timestamp: February 16, 2014, 08:12:52 pm
content: My ill-infomred understanding is that it reduces the thickness of the depletion region -http://en.wikipedia.org/wiki/Depletion_regionis most likely the Wikipedia page you are looking for.

author: free_electron
author_rank: Super Contributor
timestamp: February 16, 2014, 08:15:56 pm
content: potential. hardness or thickness of diffusion controls current

author: CaptnYellowShirt
author_rank: Frequent Contributor
timestamp: February 16, 2014, 08:59:57 pm
content: Quote from: free_electron on February 16, 2014, 08:15:56 pmOk. So, its overcoming the built-in bias and aiding diffusion.
Forward Converter topology confusion - Page 1
Forum section: electronics / beginners

author: khatus
author_rank: Regular Contributor
timestamp: September 06, 2021, 05:26:40 pm
content: Hello guys i have some confusion about forward converter Topology.Here What does it mean by catch action of diode ??I can not understand how does Dot end of Nr will be clamped at one diode below ground?? Can anybody explain with pictures??

author: iMo
author_rank: Super Contributor
timestamp: September 06, 2021, 05:34:11 pm
content: As they write - the Nr_dot goes negative (against GND), and the D1 gets conductive (as the anode=GND is positive against cathode). So it clamps Nr_dot (aka Vdk) at aprox -0.7V ..

author: khatus
author_rank: Regular Contributor
timestamp: September 06, 2021, 06:55:53 pm
content: Hello, Which software you have used for simulation?

author: iMo
author_rank: Super Contributor
timestamp: September 06, 2021, 06:56:54 pm
content: https://www.analog.com/en/design-center/design-tools-and-calculators/ltspice-simulator.html

author: David Hess
author_rank: Super Contributor
timestamp: September 06, 2021, 08:30:24 pm
content: When the transistor is on, it charges the magnetizing inductance of the transformer. When the transistor turns off, the stored flux in the transformer reverses the voltage on all of the windings. This would increase the voltage across the transistor to an unacceptable level but instead the diode "catches" it when the voltage it sees tries to go below ground. At that point, the energy stored in the transformer is returned to the input.

author: iMo
author_rank: Super Contributor
timestamp: September 06, 2021, 09:33:58 pm
content: .
Found a -24v power supply. ?? - Page 1
Forum section: electronics / beginners

author: badjob
author_rank: Contributor
timestamp: January 14, 2019, 12:41:09 am
content: So I found a power supply with:+3.3, +5, +12 and -24vIf I want to use the -24v to power a device do I hook up PS ground to the positive and then -24v to the negative? Will this work as a normal +24v power supply would have? And then using -24v with +12 or +5 would create higher voltages like 36v and 29v? I've never used negative sources and some googling seemed to imply this.

author: jcw0752
author_rank: Contributor
timestamp: January 14, 2019, 02:39:45 am
content: What you say is correct but you may be limited by the current rating of the different supplies. For example if the -24 V is rated at one amp and the + 12 V is rated at 5 amps the using them in series would provide you with 36 volts but the current would be limited to the one amp of the -24 volt source.John

author: registereduser
author_rank: Contributor
timestamp: January 14, 2019, 02:58:59 am
content: I just found this recently.https://pcbsmoke.files.wordpress.com/2015/03/voltage-combinations-650.png

author: badjob
author_rank: Contributor
timestamp: January 14, 2019, 05:37:58 pm
content: I hooked it up and tested with dmm. +12 and -12 give 26v with no load. -24 gives 22ish volts with no load. There is no amp rating on the power supply but the model+ is 40-vp5120-PWD1X.Hope its at least 1 or 2 A. Any way to figure that out?

author: mikerj
author_rank: Super Contributor
timestamp: January 15, 2019, 07:36:32 pm
content: That PSU appears to be from an old Philips DVP3040 DVD player. The power consumption of that device is specified atless than 10 Watts total, so it's very unlikely you will be able to pull 1 Amp out of the 24v rail.
found a USB port on a machine.... - Page 1
Forum section: electronics / beginners

author: Swake
author_rank: Frequent Contributor
timestamp: March 30, 2018, 08:10:06 am
content: Hi,I have a machine and would like to 'interface' with it to read out the many sensors it has.There is a board with a micro USB connector on it. Is there any danger to break something if I connect a portable computer on that port?Obviously I can mess up the software/firmware/settings/whatever, my question is more about the physical interface and the electric side. USB is USB right?

author: DC1MC
author_rank: Super Contributor
timestamp: March 30, 2018, 08:22:59 am
content: IF (a big if) there is really an USB interface and not some bullshit thing that uses the same connector, I had an (expensive) Toshiba TV with an USB connector marked "Update Port", stick an USB stick into it and watch he whole TV die, because was some complete different interface.But most likely they won't do this anymore, hopefully.

author: Rerouter
author_rank: Super Contributor
timestamp: March 30, 2018, 08:26:27 am
content: Easy confirmation would be to make sure therr is 5v and ground on the correct pins. And nothing weird on the data pins.Next up from that would be hoping it enumerates as a standard device. Or array of devices with a windows findable driver.If not. Then fuzzing begins.

author: Twoflower
author_rank: Frequent Contributor
timestamp: March 30, 2018, 08:56:08 am
content: Probably a good idea is also to not connect it directly to your Computer. Use a USB-Hub in between. If something went wrong you might be lucky by just replacing the hub and not your computer.

author: ebastler
author_rank: Super Contributor
timestamp: March 30, 2018, 10:28:16 am
content: Would you mind telling us what "machine" that is?Do you have a manual, or have you looked for one?Seems like a good idea to look up the function of that connector before you start messing around with it...

author: johnkenyon
author_rank: Regular Contributor
timestamp: April 04, 2018, 01:43:24 pm
content: Quote from: DC1MC on March 30, 2018, 08:22:59 amI knew a piece of telecoms equipment which had a "local craft interface" connection (aka RS232 serial port) which presented a USB mini socket.This created the double hazard of (A) someone using a standard USB cable to connect a PC USB port to RS232, or (B) someone using the bodged DE9 to Mini USB cable to apply RS232 levels to $USB_DEVICE.For the want of £3 and a bit of PCB real estate they could have made it native USB...
Found This - Page 1
Forum section: electronics / beginners

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: May 05, 2013, 11:21:10 pm
content: I found this today and thought this would be good for newbies or anyone else ,so Check it outhttp://blog.makezine.com/projects/how-to-professional-perfboards/

author: Dave
author_rank: Super Contributor
timestamp: May 05, 2013, 11:46:04 pm
content: Professional perfboards, an oxymoron.Just learn how to make your own PCBs. The toner transfer method is really simple and reliable. I have had success with a fairly large (20cm x 10cm) double sided PCB with small vias (1mm diameter, 0.5mm hole).

author: TorqueRanger
author_rank: Frequent Contributor
timestamp: May 05, 2013, 11:52:46 pm
content: Quote from: Dave on May 05, 2013, 11:46:04 pmWith my kids I can't really etch boards and especially in a 2 bedroom apartment and the work space is the kitchen table ... But it just helps you with layout process and dresses it up a bit lol....

author: LEECH666
author_rank: Frequent Contributor
timestamp: May 06, 2013, 11:58:40 am
content: https://www.eevblog.com/forum/beginners/perfboard-prototyping/msg178067/#msg178067Sorry for the crosslink. I find this tool pretty good for laying out perfboard. Maybe you will find it useful as well.