hybridfree/eevblog-posts huggingface dataset:
Electric Skateboard Remote - Schematic Review - Page 1
Forum section: electronics / beginners

author: cmkluza
author_rank: Newbie
timestamp: January 02, 2020, 03:39:26 am
content: Hey all,I'm making a PCB for an electric skateboard remote. On the back of lots of mistakes with my first PCB project, I'm hoping you guys might spot any silly mistakes I'm making with this one.It's going to be using an nRF82540 for BLE communication to the skateboard. It'll be powered by a single 3.7V li-ion cell, charged through micro-USB. In terms of I/O, I'm taking inspiration from e.g. how SolidGeek did their nRF24-Esk8-Remote (https://github.com/SolidGeek/nRF24-Esk8-Remote) and how Boosted does their remote - a thumbwheel that moves a magnet detected by an analog hall sensor and some buttons. There's a buzzer for audible feedback and an LCD for visible feedback (I'll probably add some LEDs too).Stylistically I see I've got some inconsistent designator/info placement, and also lots of empty space to spread things out into once I'm more settled on the schematic.Functionally, the only thing I'm thinking of right now is maybe going back through and adding more test points wherever I think it might help firmware development. I've also heard that ESD protection on the USB lines isn't very necessary - maybe I should just DNP those for now? This certainly isn't going to be a consumer product.As an aside, I'm new to the forum, so not sure the best format to give the schematic - I've attached the Altium "smart" PDF as well as some PNGs of it.Looking forward to any feedback, tips, advice, etc!- Cameron
Electric Trike Build - Page 1
Forum section: electronics / beginners

author: StrayCitizen
author_rank: Newbie
timestamp: November 26, 2015, 02:03:08 pm
content: Hi Guys Im Wondering If You Can Help Me With Some Simple Circuit Design1. I Need A Charge Controller For My Deep Cycle Battery 35ah for 10hrs2. I Need A Filter Circuit For 2KW 50v 60A For My MotorI Would Use A Cap Bank But Im Not Sure It Filters Current, Im Familiar With Electronics But Not With Advanced CircuitsThanks For Your Help
electrical "creepage" of spray paint ? - Page 1
Forum section: electronics / beginners

author: 3roomlab
author_rank: Frequent Contributor
timestamp: June 12, 2014, 06:55:47 am
content: i was wondering, if anybody had any experience, if you were to just spray normal paint can spray on dense populated electronics like motherboards, wont you be changing on a "large scale" the parasitic capacitances ? (and some resistances?)the reason i asked or seek some feedback is because, ASUStek released a concept mobo (http://yournewsticker.com/wp-content/uploads/2014/06/Asus-TUF-Sabranco-Z97-and-TUF-Sabertooth-Z97-MK2-1.jpg)it adds a kind of shell, it looks ... different from generic naked mobos, but it does seem to help "protect" the delicate exposed mobo somehow (nasty roaches attacking?)then i saw this pix from a german forum, this guy repainted his mobo directly (http://extreme.pcgameshardware.de/news-kommentare-zu-mainboards-und-ram/336698-weisses-asus-tuf-sabranco-und-sabertooth-z97-mark-2-gesichtet-2.html)i have not really heard that spray paint gets in the way of circuits much, but high frequency digital logics?or is there an electrically inert spray paint so to speak? maybe not a spray, a brush applied inert paint even?

author: nihilism
author_rank: Regular Contributor
timestamp: June 12, 2014, 02:08:37 pm
content: http://www.dowcorning.com/content/etronics/etronicscoat/etronics_cc_tutorial.asp?DCWS=Electronics
Electrical Connector Maker Question - By Logo - Page 1
Forum section: electronics / beginners

author: PMK145
author_rank: Newbie
timestamp: July 30, 2025, 05:55:59 pm
content: HiA newbie here with a question about an Amscope microscope LED light connector. Does anybody recognise this logo please? 'Lechen' maybe but that produces no Google hits?The light's base unit has 2-off 4-pin sockets to accommodate two LEDs mounted on goosenecks. I'm trying to fir an extension cable because the base unit won't fit on my tiny workbench/desk with the soldering matCheersPete

author: PMK145
author_rank: Newbie
timestamp: July 30, 2025, 08:01:01 pm
content: Aha! It's 'Kechen' which I had searched with Google but the results were hidden by its assumption that I meant 'kitchen'.A manufacturer in China whose wares apparently aren't freely available here in the UK.
Electrical Estimates for a 1602 LCD Display/3V3/I2C/Blue? - Page 1
Forum section: electronics / beginners

author: t1d
author_rank: Super Contributor
timestamp: February 02, 2022, 01:58:55 pm
content: I have ordered this display to play with:https://www.amazon.com/gp/product/B0821CM134/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1Of course, there is not a data sheet for it. Google was no help.I need to make sure that my power supply will support the requirements of the entire project. I am using a wall wart and their amps are always overstated, meaning that, when they are loaded to their rated amperage, their output falls below their rated voltage = voltage droop... Even past acceptable tolerances...I want to do some load tests on the wart using equivalent resistors, or my DIY E-Load, before assembling the project. I have the data sheets for the other components. I just need to know the total current draw for the entire LCD Module Assembly (including the I2C Converter) and the bare minimum voltage required to run it reliably. Then, I can finish the calculations. (Of course, I can wait for the units to arrive and test them, myself. I just wanted to try to get ahead...)So, what might be the typical electrical specifications that I might expect to encounter? Thank you for your help.PS - No need to point out that I should not buy cheap stuff that does not have a data sheet. I am aware of that and I have my (personal) reasons to have done so. But, I appreciate your wisdom and concern.

author: Ian.M
author_rank: Super Contributor
timestamp: February 02, 2022, 02:12:27 pm
content: Blue LED backlight + 3.3V supply implies the backlight current will be highly dependent on the exact supply voltage as the Vf of a blue LED is typically approx 3V so the series current limiting resistor is going to be small and minimally effective.TLDR: you are going to have to wait to 'suck it & see'!

author: Renate
author_rank: Super Contributor
timestamp: February 02, 2022, 07:01:33 pm
content: Blue LEDs suck.I reengineered a consumer product that used 4 x AAA batteries just so they could do blue LEDs.It now uses yellow LEDs and 2 x AAA batteries and has storage room for a spare pair of batteries.Darn that Planck's constant!

author: rstofer
author_rank: Super Contributor
timestamp: February 02, 2022, 07:12:32 pm
content: That display looks a lot like the one in the various FreeNove Starter Kits - maybe download their manual and see how it turns out:https://www.manualslib.com/brand/freenove/https://www.amazon.com/dp/B06W54L7B5https://www.amazon.com/Freenove-Ultimate-Compatible-Solderless-Breadboard/dp/B08B4D5MV5The ELEGOO version of the Starter Kit is one day deliveryhttps://www.amazon.com/ELEGOO-Project-Tutorial-Controller-Projects/dp/B01D8KOZF4/

author: rstofer
author_rank: Super Contributor
timestamp: February 02, 2022, 11:03:17 pm
content: I have that exact display in my Freenove Raspberry Pi Starter Kit. The tutorial says to run it at 5.0 V and I get 22.3 mARaspberry Pi logic levels are 3.3V and the pull-up resistors are on the Pi.
Electrical load for R&R study on safty and function tester - Page 1
Forum section: electronics / beginners

author: DanielP
author_rank: Newbie
timestamp: February 27, 2019, 09:31:16 am
content: Hy,I am newbie in this forum, looking for a few hints related my new project.I found the introduction of those forum really cool, that is why i writing my question here:I am going to do Gage R&R study on universal safety- & function testersDuring the studies, I would like to check the tester these 3 functions:- ground bond resistance measuring - 2.0 Ohm at 30A- insulation resistance measuring - 2.0 Ohm at 500V DC- funkcion test, current measuring,1.0 sec./ measuring 30 ok and 30 nok measuring per funkcion for the R&RFor this my plan to build a constant load simulating a LED luminaire, with datas:- nominal voltage: 230V- power: 34.0 W- Apparent power: 35.6 W- Cos phi (power factor): 0.96- constant resistances for ground bond resistance and insulation resistance measuringCan someone help me, where can I found infromations, examples or advices about using long term stabil loads for calibration or R&R?in the ranges mentioned above?Tester: Schleich GLP2 (https://www.schleich.com/en/produkt.php?ProduktID=185)Thanks a lot for the help, br: Dani.
Electrical Symbol - Page 1
Forum section: electronics / beginners

author: bitman
author_rank: Unknown
timestamp: September 02, 2017, 06:02:58 pm
content: In the diagram below there's something that looks like a thermistor but has an extra line on it. What kind of component is that? Thermistor doesn't really make sense in the diagram as far as I can see, but I wonder if it's related since the symbol is pretty close to one.

author: IanB
author_rank: Super Contributor
timestamp: September 02, 2017, 06:05:01 pm
content: MOV - metal oxide varistor?https://en.wikipedia.org/wiki/Varistor

author: TimFox
author_rank: Super Contributor
timestamp: September 02, 2017, 07:02:04 pm
content: "NTC" is a negative temperature co-efficient thermistor."MOV" is a metal-oxide varistor (similar to back-to-back zeners).
Electrically Opened, Manually Resetable, Relay/Breaker/Switch?  - Page 1
Forum section: electronics / beginners

author: psteichen
author_rank: Contributor
timestamp: April 26, 2014, 04:36:54 pm
content: I have a heater with an overheat cutout switch. Unfortunately the manufacturer designed it with a switch that resets itself when it has cooled a bit. Sounds like a good thing, but it's not. When the filter clogs up triggering an overheat cutout, it results in a never-ending cycle of overheating/resetting. This results in the overheat sensor burning out after a week or so if we don't notice.I'd like to modify the circuit so that if the circuit is broken by the overheat sensor it stays broken until I manually reset it. The circuit is 24VAC. My thoughts are to create a circuit that will monitor the situation, and if the overheat sensor cuts the circuit while it is live a manually resetable switch will be opened in the overheat sensor circuit thus keeping it open.I will also make it so that my backup heating source is triggered, and a small buzzer will be activated to remind us to change the filter.But my problem is I've never used a manually resetable switch that can be electrically opened. I don't even know what to call such a thing. I considered using a circuit breaker and simply grounding out the circuit to force a trip upon the overheat sensor resetting itself, but this would probably cause the fuse that runs the whole system to blow as well and is certainly not ideal even if it worked.Any advice would be appreciated.

author: Pillager
author_rank: Unknown
timestamp: April 26, 2014, 05:03:30 pm
content: Why not just build a simple latch circuit with a relay?Use the cutout switch to reset the circuit and a simple push button to set it.Then use the relay to switch the heater and whatever else comes to mind.Of course, you will have to push the button to start the heater, when you had it unplugged, but let's call it a feature

author: Pillager
author_rank: Unknown
timestamp: April 26, 2014, 05:25:26 pm
content: See circuit:When you press S1, the relay switches and latches via the contact next to S1.When T1 (your cutout switch) opens, the relay returns to its original state and won't switch again, until you press S1.Then you can use the other relay contact to switch your heater (make sure the relay can handle the load!). If you need more contacts to switch stuff, just get a relay with 4 or more contacts...

author: SeanB
author_rank: Super Contributor
timestamp: April 26, 2014, 05:50:33 pm
content: Just buy a thermal cutout with a manual reset option. Klixon makes them in assorted temperature values and they are the same as the existing switch. You just have to make an insulated rod to reach in and press the reset button, or just have it behind a cover that has a disconnect safety switch and needs tools to open for safety.
Electric/Electronic online stores - Page 1
Forum section: electronics / beginners

author: jabalv
author_rank: Contributor
timestamp: February 18, 2019, 07:57:48 pm
content: Where you guys are buying electronic/electric parts etc.?1) Is there any good website with detailed specifications - technical, dimensions etc.2) Online stores that contain widest choice of parts like - electrical cables, electric isolation, electronic components, switches etc.3) Delivery in EuropePlease share your online stores.I'm currently searching for specific parts (industrial strength cables, auto/truck switches with 24V 8A/16A ), but in general would be nice to know any good online stores which match my criteries.Searching in aliexpress, but most of that stuff lacks real technical documentation and it is limited with choice, website filters are terrible - not detailed at all.

author: alanb
author_rank: Frequent Contributor
timestamp: February 19, 2019, 03:11:48 pm
content: RS Components, Farnell and Digi-key all have wide ranges of parts and technical info. They all as far as I am aware deliver in Europe.

author: FrankE
author_rank: Regular Contributor
timestamp: February 19, 2019, 05:05:19 pm
content: RS, Farnell mainly and DigikeyI used TME once but I'd rather stick to UK suppliers.

author: timgiles
author_rank: Regular Contributor
timestamp: February 19, 2019, 06:14:00 pm
content: Mouser - delivery to sweden is free, no import duties (imported to France first which seems to get round the cost), reasonable prices, huge selection and fantastically fast.TME - reasonable however sometimes it is hard to understand when orders will be shipped and they can be split up, postage costs, .....I can order and receive it in exactly 7 days. I can order from companies within Sweden, who have stock, and I have to pay for postage and it usually takes longer to arrive..... Highly impressed.

author: lpaseen
author_rank: Contributor
timestamp: February 19, 2019, 06:25:06 pm
content: When looking for components and component sources I many times usehttps://octopart.com/besides finding the component it lists several places to get it and you can even make some of them your favorite so the show up first.

author: Moriambar
author_rank: Unknown
timestamp: February 19, 2019, 07:58:36 pm
content: I use rs, digikey, mouser, farnell mainly (all deliver in europe). I also use lcsc, but only when ordering a pcb also. Never had problems with any of those.

author: Km
author_rank: Newbie
timestamp: February 21, 2019, 10:51:40 am
content: i use aliexpress and rs online

author: jackthomson41
author_rank: Regular Contributor
timestamp: February 21, 2019, 12:48:14 pm
content: Rs components is best among all, they also have technical team for help. I once boughtULN2003&ULN2803from them.

author: Nitrousoxide
author_rank: Regular Contributor
timestamp: February 22, 2019, 05:22:16 am
content: I personally use Arrrow. Good stock and they have free shipping, even to Australia! It arrives in good time (no more than 3-5 days).
Electrnics market/shop in Guangzhou - Page 1
Forum section: electronics / beginners

author: nimaina
author_rank: Newbie
timestamp: March 17, 2014, 11:41:08 am
content: Hi folks,I'll be in Guangzhou, China for a few months and wondering if there's any electronics market/shop there?I mean a real physical shop not the online ones. Please recommend..

author: kizzap
author_rank: Unknown
timestamp: March 17, 2014, 12:01:56 pm
content: are you serious? Shenzhen is literally an hour and a half away.train/bus/drive down. Never leave.

author: EEVPiobee
author_rank: Contributor
timestamp: March 18, 2014, 08:39:55 am
content: --nevermind, misread--
Electrolux Washing machine motor driver - Repair? - Page 1
Forum section: electronics / beginners

author: Formula400
author_rank: Newbie
timestamp: June 06, 2022, 03:03:00 pm
content: Just replaced a motor driver for a industrial size washing machine at work. I work as a janitor and had telephonic support from a service technician to identify the problem with this washer. Replacing the motor driver unit solved the problem with the machine. Btw - The washer initially displayed an error message indicating motor driver malfunction.Just out of curiosity i have now had a closer look at the motor driver. Only obvious sign of damage is a heat damaged diode. See picI believe this is a Philips BZD142W based on the identifier number 12 on the SOD87. This is also supporter by the fact that thehttp://www.ic72.com/pdf_file/b/154774.pdf]ZenBlock application note http://www.ic72.com/pdf_file/b/154774.pdf mention this:QuoteThe TNY254GN next to the damaged diode is in fact a PWM controller.Any thoughts on the failure mode and is it possible to find parts to repair this? Should i just give this up or can a guy like me with just basic electronics and soldering skills fix this?

author: m k
author_rank: Super Contributor
timestamp: June 13, 2022, 07:53:11 pm
content: I don't like what I'm seeing.Heat around the diode is not the issue but pin 5 of the chip is also colored and zener voltage can be 200V.My estimation for your success is low.

author: wraper
author_rank: Unknown
timestamp: June 13, 2022, 07:57:13 pm
content: IMHO high voltage zener diode is used in snubber circuit. If it became shorted, TNY254 likely failed as well and blew a fuse. Seems like an easy repair.

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 13, 2022, 08:33:24 pm
content: Seems to be a typical appliance failure now, those little "SMPS on a chip" ICs failing, to a point I've seen parts kits offered for more common consumer stuff.

author: Formula400
author_rank: Newbie
timestamp: June 26, 2022, 08:55:12 pm
content: Quote from: wraper on June 13, 2022, 07:57:13 pmQuote from: BrokenYugo on June 13, 2022, 08:33:24 pmThank you all for taking your time helping me!What failed first we will never know i guess. I was already thinking about replacing both components. Great! I was hoping this would be an easy fix! If the parts are easy to find online i will make an attempt to repair this. The board have diagnostic LED's so i assume i can power it up on the workbench and verify it is happy in standby modeThe Phillips zener diode worries me a bit. Can't find any supplier for this. Any suggestion to a substitute zener? Or even better How can i locate this myself?

author: wraper
author_rank: Unknown
timestamp: June 26, 2022, 09:21:01 pm
content: If it's really BZD142W, then you need to know its suffix as they come with different working voltage. Also it's not necessarily bad, probably it is not. Sure it was stressed as hell as darkened PCB shows but it could survive too.

author: m k
author_rank: Super Contributor
timestamp: June 28, 2022, 08:42:11 am
content: Changing components and repairing are two different things.Remove carbon also and restore connectivity.
Electrolytic broth - Page 1
Forum section: electronics / beginners

author: vodka
author_rank: Frequent Contributor
timestamp: September 03, 2016, 05:40:05 pm
content: Yesterday , i was searched a capacitor on a lunchbox where i keep all huge capacitor from old PCB scraping.I found almost all capacitor coated with a sticky liquid that i think that is electrolyticToday , i decided to clean and testing the capacitors and i found 7 suspects and 5 deads(without external evidence).Of the suspects, i have seen that practically there aren't nothing ,only i can see a few very small drops on the bottom capacitors that i don't know if is a leakage or a dry electrolytic.But the more strange is that the lunchbox was quite dirty of electrolytic.Where has it gone out so much electrolytic ,when i haven't found any hole or slice on the capacitors ?

author: bob1033
author_rank: Contributor
timestamp: September 05, 2016, 09:48:44 pm
content: The capacitors were most likely leaking from the bottom bung used to seal the bottom of the capacitors. I've seen this in a few bad power supplies I've repaired. Some of the cheaper capactors use a natural rubber rather than a synthetic one that can shrink over time and lose a good seal. The shrinkage of the rubber probably wouldn't be too obvious other than leaking electrolyteMy guess anyways
Electrolytic Cap in PCB - Page 1
Forum section: electronics / beginners

author: NMP
author_rank: Contributor
timestamp: October 18, 2016, 10:03:30 am
content: Hi all,I just made a project with a uP, check all the datashets, folow the decoupling rules and some evm of the components, made the firmware and It all was working well.with 3 or more boards connected to the same power supply, if i insert a new one, or disconnect and connect one of them, all the boards make a reset.If i put a Electrolytic cap on each one all works well.Does anyone know how can i prevent/read this?

author: tszaboo
author_rank: Super Contributor
timestamp: October 18, 2016, 10:14:06 am
content: Without knowing more about the setup, I would say, as a general rule:Include a "bulk" electrolytic capacitor on your PCB, if possible, one per rail. They have ESR, which helps dissipating transients, they provide current when it is needed, they reduce the current spikes, and intermittent voltage drops on cables.

author: danadak
author_rank: Super Contributor
timestamp: October 18, 2016, 10:14:35 am
content: Post schematic and identify the electrolytic you are adding.Regards, Dana.

author: NMP
author_rank: Contributor
timestamp: October 18, 2016, 11:02:43 am
content: Thank's!!One per Rail makes sense..I have it all in SMD, I see some tantalum, big yellow ones in a lot of projects, but there are some 0805 for instance 47uF, do you think it whould do the job?

author: Jeroen3
author_rank: Super Contributor
timestamp: October 18, 2016, 01:32:29 pm
content: Quote from: NMP on October 18, 2016, 11:02:43 amBeware, those are expensive and low voltage.

author: tszaboo
author_rank: Super Contributor
timestamp: October 18, 2016, 01:39:12 pm
content: Quote from: NMP on October 18, 2016, 11:02:43 amWell, the 0805 47uF will have 0.1 Ohm ESR, similar size tantalun will have 1 ish Ohm. Look up "snubber". Also, look up the voltage dependence of the ceramic capacitor and the electrolyte.

author: janekm
author_rank: Unknown
timestamp: October 18, 2016, 02:12:59 pm
content: Also you can get SMD versions of electrolytic caps.

author: mariush
author_rank: Super Contributor
timestamp: October 18, 2016, 02:22:02 pm
content: There's also surface mount polymer capacitors ..example polymer-aluminum :https://na.industrial.panasonic.com/products/capacitors/polymer-capacitors/sp-cap-polymer-aluminumor polymer-tantalum :https://na.industrial.panasonic.com/products/capacitors/polymer-capacitors/poscap-tantalum-polymer
Electrolytic capacitor ESR confusion  - Page 1
Forum section: electronics / beginners

author: valley001
author_rank: Frequent Contributor
timestamp: March 18, 2019, 12:56:52 am
content: I am in the process of recapping a Fluke 332D. Once cap has failed on it so far and I would rather not chase bad caps over the next 10 years so I have decided to simply replace as many of the electrolytic as I can (reasonable?)Three of the caps are 450v 8uf +50/-10%. I found KEMET PEG124YF2100QL1 450v 10uf however the quoted ESR is 5.7 ohms. Is this a normal ESR figure for this type of capacitor? My noob impression is that ESR should be less than an ohm. I just want to be sure I install a cap that will work properly. Thanks in advance for the education.

author: helius
author_rank: Super Contributor
timestamp: March 18, 2019, 01:12:48 am
content: High voltage, low capacitance devices have high ESR as a result of their physical construction. That is perfectly normal.I would probably not replace all capacitors at once because there is a risk of damage with any kind of rework.

author: valley001
author_rank: Frequent Contributor
timestamp: March 18, 2019, 01:19:06 am
content: Quote from: helius on March 18, 2019, 01:12:48 amIs this risk lower than a cap going sideways? I worry about a sideways cap taking out other more unobtainable parts.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: March 18, 2019, 01:19:46 am
content: Hi,Less than 1is a simplification.A lot of commonly encountered values will be less than 1, but if you look at the Kemet datasheet:https://www.mouser.ca/datasheet/2/212/KEM_A4011_PEG124-1104316.pdfYou will see that some low capacitance and higher voltage electrolytic capacitors are more than 1ESR.The Kemet part you have chosen is probably better than the part that was used originally.Do you have a method foe measuring ESR?Regards,Jay_Diddy_B

author: valley001
author_rank: Frequent Contributor
timestamp: March 18, 2019, 01:29:47 am
content: Thanks everyone for chiming in. I use one of those cheap component testers for measuring ESR.
electrolytic capacitor new brand out of range - Page 1
Forum section: electronics / beginners

author: Groovy
author_rank: Newbie
timestamp: July 23, 2016, 07:58:33 am
content: Hello,I have a little problem with some capacitors i bought.they are new brand and rated 470µf 10V it's polarized capacitor.i tested them with some tools. a Chinese Fluke multimeter (Fluke 101) the MK-328 TR\LCR\ESR tester and a kit i got for 12USD (the IC is the atmega328P)all of them show me a normal ESR but the capacity is really higher 680µf that's normal?PS: i tested lots of capacitor new brand and they always are around the capacity that is write on them and also have a normal ESR(sorry if my English is not really good i'm French)

author: amyk
author_rank: Super Contributor
timestamp: July 23, 2016, 10:20:09 am
content: A leaky cap will often show high on capacitance meters.

author: Groovy
author_rank: Newbie
timestamp: July 24, 2016, 09:33:18 am
content: Thanks for the replyAnd yeah i see this is what i was thinking. that one is +60%i have a good solution for electronic now. i can buy on Conrad's website. with them, it's sure the quality is okand the price good.i was looking for a regulator (L7808CV) on ebay it's 1.60EUR (1.75USD) on Conrad it's 20Cts so.....ebay for electronic part is really not a good solution it's ok for parts that are really hard to findThanks again for have reply to me

author: 3141592
author_rank: Regular Contributor
timestamp: July 24, 2016, 09:59:49 am
content: You might also want to tryhttp://www.tme.eu/fr/,Conrad is quite expensive and limited in my experience, although I'm not in France. Farnell, Digikey (shipping may be pricey) might also be options. Compare prices, if you need something expensive.

author: Groovy
author_rank: Newbie
timestamp: July 24, 2016, 02:56:35 pm
content: ok! coolThanksi'm going to look on it. it's on my bookmarki know Mouser but it's impossible to buy there for me the shipping is really too much but yeah, that's on the USA it's really bad because they have really lot of things that i can't get easily here. also, i think i already look at Farnell and Digikey and yeah, the shipping....Thanks for the help
Electrolytic capacitor placed with the wrong polarity - Page 1
Forum section: electronics / beginners

author: Trozze
author_rank: Newbie
timestamp: June 25, 2019, 09:09:07 am
content: After recapping a dead CRT monitor chassis board with over 50 caps (Yes I checked several times but missed it) I managed to put one cap the wrong way aroundand it vented, so I replaced it.The CRT is now up and running, however it has some small horizontal interference/ghosting on some bright parts of the image... Might be the tube, maybe something broke when the cap vent on backwards.This made me thinking.. we all know what happens when you put a cap backwards - it vents or explodes, but what happens to the circuit during and after this?It’s a cap for smoothing the 12v line, when and after a cap fail this way, does it short circuit, acts like a resistor, still works somewhat but with out of spec?

author: Zero999
author_rank: Super Contributor
timestamp: June 25, 2019, 10:15:14 am
content: Firstly the capacitor will present a short circuit to the circuit, then after all the electrolyte has boiled off and it's vented, it will go open circuit again, with a capacitance much smaller than the rated value.
Electrolytic Capacitor questions - Page 1
Forum section: electronics / beginners

author: Joule Thief
author_rank: Regular Contributor
timestamp: June 20, 2014, 04:04:48 am
content: I am in the process of repairing a HP 6237B triple output power supply ( 0.5 volt ripple on ALL outputs).The problem seems to be centered around a dried out metal can electrolytic cap in the REF and BIAS supply. 13 volts of ripple on the cap is not helping.My question is in regards to the value of this capacitor. The value is marked as 490uf at 85 volts. Why would the design spec out 490uf when 470 uf would be a more common value? Is it possible 470 was not available in an appropriate form factor and a 490 cap was available ? I can't believe 20uf would make a difference in the circuit performance.

author: c4757p
author_rank: Super Contributor
timestamp: June 20, 2014, 04:09:57 am
content: Typical HP, they used all sorts of bizarre capacitor values. Just use 680uF

author: SeanB
author_rank: Super Contributor
timestamp: June 20, 2014, 04:34:46 am
content: 470uF 160V is a common value, and will likely fit as well. The only reason HP used odd values was because they made the capacitors themselves, or were buying enough to specify a value that was the maximum a manufacturer could stuff into a can.

author: Hydrawerk
author_rank: Super Contributor
timestamp: January 26, 2019, 11:14:16 pm
content: What is this capacitor? Is it a RD series fromSamwha?http://www.samwha.com/electric/product/list_pdf2/RD.pdf

author: Electro Detective
author_rank: Super Contributor
timestamp: January 26, 2019, 11:37:35 pm
content: Buy a handful of assorted (not in a packet) 470 uf caps from a local electronics parts shop, and I'll bet one or two of them will kick in at 490 ufor... if you're in good with the staff and or a regular customer (like me) bring in a cap tester/multimeter and explain what the deal is, and they usually say okand may help you sort some out too on the counter if the shop isn't busyBest to go when it's the slow part of the day and the staff aren't 'multitasking'FWIW: I discharge/short the unsuitable value caps after testing, before returning them to their spot in the shopI do the same test biz with resistors and potentiometers when I need a freaky value or matched pairs/quads etcIt saves time, money, online purchase headaches, keeps the shop in businessand fellow electronerds in a job

author: tkamiya
author_rank: Super Contributor
timestamp: January 27, 2019, 03:20:23 am
content: If tolerance of them are like many, there IS no differfence between 470 and 490. Electro-dialetic capacitors can vary as much as 100% on PLUS side.
Electrolytic capacitor replacement - Page 1
Forum section: electronics / beginners

author: NH-GrizzlyBear
author_rank: Contributor
timestamp: November 14, 2015, 08:35:05 pm
content: Hi,On one of Dave Jones videos, he talked about replacing capacitors; to use a higher uF value with a working voltage the same or higher if the value you're replacing is unavailable. How much larger can it be?I'm currently trying to fix a 'Panasonic DMR-E85H DVR' and one of the leaking caps was 56uF@35V. The closest value in my stock was 100uF@35V. Is this acceptable for the long term?Also, I'm trying to locate a data sheet for a 'sub only coupler', part number B3PBA0000078 which drives a switching ic, part number C0DACZH00004 which gets its power supply filtered by the 56uF cap.Any help is greatly appreciated!

author: Simon
author_rank: Unknown
timestamp: November 14, 2015, 08:37:04 pm
content: Any idea what the capacitor is doing ? if It's a bypass capacitor bigger is fine although you could end up with a higher ESR that could cause problems. If it's say part of a filter you may want the right value.

author: NH-GrizzlyBear
author_rank: Contributor
timestamp: November 14, 2015, 08:45:45 pm
content: Quote from: Simon on November 14, 2015, 08:37:04 pmDHere is a portion of the schematic (a little blurry-sorry). The cap high-lighted in orange is 56uF.

author: Simon
author_rank: Unknown
timestamp: November 14, 2015, 08:47:21 pm
content: It's a bypass by the looks of it. Should be ok if your replacement is good quality

author: NH-GrizzlyBear
author_rank: Contributor
timestamp: November 14, 2015, 08:56:42 pm
content: Quote from: Simon on November 14, 2015, 08:47:21 pmSo, I can keep the 100uF? Any ideas.how to get data sheets for the other parts in question, as VCC is mV and F/B voltage is also low, coming from Q1200 (only about 1V at the diode of the coupler).

author: Simon
author_rank: Unknown
timestamp: November 14, 2015, 08:58:06 pm
content: Other than google voodo I can suggest much.

author: marco99
author_rank: Newbie
timestamp: December 17, 2015, 05:58:17 pm
content: Quote from: NH-GrizzlyBear on November 14, 2015, 08:56:42 pmHi, I have the same DVD recorder and have to replace the 56uf cap and 5 others that are leaking...how did you make out with the 100uf.Thanks

author: NH-GrizzlyBear
author_rank: Contributor
timestamp: December 18, 2015, 12:00:43 am
content: Quote from: marco99 on December 17, 2015, 05:58:17 pmTurns out that the reason the 56uF blew was that both the 1.8V and the 3.3V regulators were failing under load! Changing the 100uF was moot.

author: marco99
author_rank: Newbie
timestamp: December 18, 2015, 01:35:14 pm
content: Thanks for the info

author: marco99
author_rank: Newbie
timestamp: December 19, 2015, 11:43:38 pm
content: I replaced the 56uF with a 47uF and 10uF in parallel (along with two 680uF and two 220uF)It's working now......
electrolytic capacitor - Page 1
Forum section: electronics / beginners

author: pete g
author_rank: Regular Contributor
timestamp: April 11, 2023, 06:27:45 pm
content: how does leakage(parallel) in an electrolytic cap affect capacitance?

author: wasedadoc
author_rank: Super Contributor
timestamp: April 11, 2023, 07:03:11 pm
content: It does not affect the true capacitance. It may affect (reduce) the capacitance value indicated by some capacitance meters. It may also reduce the effective capacitance in some circuits such as timing circuits.

author: srb1954
author_rank: Super Contributor
timestamp: April 12, 2023, 01:24:46 am
content: Quote from: wasedadoc on April 11, 2023, 07:03:11 pmOr it could increase the effective capacitance. It depends on the configuration of the timing circuit.If you have a capacitor charging up to a threshold voltage e.g. in a 555 timer circuit, the effect of leakage will be to slow the charging rate and it takes longer to reach the threshold voltage. The effective capacitance thus appears to be larger in this case.

author: pete g
author_rank: Regular Contributor
timestamp: April 12, 2023, 06:14:03 pm
content: so, if i were to measure a cap with an esr meter, a leaking cap would show no evidence of leakage, the esr and cap value would not significantly change. is that correct?

author: Zero999
author_rank: Super Contributor
timestamp: April 12, 2023, 06:22:52 pm
content: Leakage will not affect the ESR. It will probably result in a higher than expected reading when the value is tested, on most multimeters. This is because the impedance is measured at a specific frequency and leakage will reduce the impedance.

author: RoGeorge
author_rank: Super Contributor
timestamp: April 12, 2023, 06:28:49 pm
content: By "leakage(parallel)" do you mean the parallel leakage resistor, or do you mean the electrolyte leaking out on the PCB and surroundings?- If it's the first, ESR/capacitance won't tell you the parallel resistance of a capacitor, you need to test for dielectric losses. A list with a few type of losses, there are more than parallel equivalent resistance:https://passive-components.eu/esr-losses-in-capacitors-explained/- If the second, if a capacitor is leaking electrolyte, most probably will show: lower capacitance, higher ESR than nominal, visual indication and/or bad smell.

author: barshatriplee
author_rank: Regular Contributor
timestamp: April 14, 2023, 09:15:04 am
content: This article discusses Electrolytic Capacitors characteristic of leakage current and how it is important to allow 'self-healing':https://eepower.com/technical-articles/electrolytic-capacitor-leakage-current/#

author: pete g
author_rank: Regular Contributor
timestamp: April 14, 2023, 02:29:51 pm
content: thanks guys, your comments were very helpful.
Electrolytic vs ceramic capacitor - Page 1
Forum section: electronics / beginners

author: anvoice
author_rank: Frequent Contributor
timestamp: March 28, 2018, 12:35:43 am
content: I have a chip with an embedded LMR16006 buck regulator and selecting the necessary components to get 3.3V for my MCU and another component. TI has a helpful simulation which determines the values of the resistors, capacitor and inductor needed for the circuit. The capacitor turns out to be 33uF: the part selector has an electrolytic capacitor in the schematic, and I'm wondering if I can get away with using a ceramic one with the same value? That would allow me to minimize the footprint and reduce cost. From what I understand the limitation of a ceramic capacitor is that its voltage rating is relatively low, but if I only need one rated for 3.3V that doesn't seem like a problem. A bigger issue I see is drift in the value in capacitance with temperature, but not sure if that will cause a problem either.Basically, should I use an electrolytic cap or will the ceramic work fine?

author: james_s
author_rank: Super Contributor
timestamp: March 28, 2018, 02:36:19 am
content: Some other things to consider. The capacitance of many types of ceramic capacitors can drop dramatically when there is DC across it, which is what you will have in a power supply. Another potential issue is that the ESR is extremely low, this is often desirable, but not always, some regulators rely on the ESR of the capacitor and will be unstable without it.

author: anvoice
author_rank: Frequent Contributor
timestamp: March 28, 2018, 03:02:39 am
content: I see. Looking at the recommended schematic closer, it has a resistance on Cout that is 0.070 Ohms. Should I look for the exact same cap, with the exact same series resistance? Or would any electrolytic cap have a similar ESR and work fine?

author: james_s
author_rank: Super Contributor
timestamp: March 28, 2018, 03:50:18 am
content: Normally anything similar will work, I've never seen one that required a very specific capacitor.

author: Jwillis
author_rank: Super Contributor
timestamp: March 28, 2018, 03:58:13 am
content: Have you considered a tantalum.

author: anvoice
author_rank: Frequent Contributor
timestamp: March 28, 2018, 05:26:21 am
content: Quote from: Jwillis on March 28, 2018, 03:58:13 amIt looks from the datasheet like both ceramic and tantalum capacitors are an option. Moreover, from what I've read a smaller ESR might be better. Specifically, they say for ceramic caps, the ESR is small enough to be ignored in the calculations for selecting the capacitor. So it doesn't seem like this regulator needs a specific ESR to operate properly. I think I'll look into 0805 ceramic caps, maybe go with a slightly higher value than the 33uF to make sure its capacitance drop with temperature doesn't cause as big a problem.Let me know if there's an error in my judgment here.
Electromagnet attracts at very small distance - Page 1
Forum section: electronics / beginners

author: mr_byte31
author_rank: Regular Contributor
timestamp: February 22, 2025, 07:33:55 pm
content: Hi Folks,I bought an electromagnet (EM) as attached in the figure. it has compact size compared to other EM that I used before. it costs around $5 and can hold 5 Kg.The EM shall be used to pull a metal bar at 10-20 mm distance.I received the EM and I find it has a strong suction power.The only issue I can found, that it attracts metal at very short distance (2-3mm) !!. I was expecting that a strong attraction power would mean large distance to attract things.is there any explanation for that ? is there anyway to modify the EM to attract metal at larger distance ?

author: benj38
author_rank: Frequent Contributor
timestamp: February 22, 2025, 09:34:13 pm
content: The exact formula for the force a magnet exerts on a piece of ferromagnetic material is not simple, and depends on the exact geometries of the metal and the magnetic field. However, a good first approximation is that the force decreases by the square of the distance. So, if you increase the distance from 2mm to 10mm, expect the force to decrease by a factor of 25.There is nothing you can really do except to get a much stronger magnet.

author: Circlotron
author_rank: Super Contributor
timestamp: February 22, 2025, 10:18:37 pm
content: You could perhaps improve things somewhat by giving the coil a quick pulse of several times the normal operating voltage for say 100mS before dropping down to normal voltage. Of course, once the core saturates the magnetic force won’t get stronger than that limit.

author: bdunham7
author_rank: Super Contributor
timestamp: February 22, 2025, 10:29:52 pm
content: Quote from: mr_byte31 on February 22, 2025, 07:33:55 pmThat electromagnet has the outer ring and inner core as the two poles. sort of like a horseshoe magnet but arranged as concentric circles. It is designed to have high force when in contact but not to act over long distances. You'd need a different design to pull in your metal bar from 20mm.

author: SteveThackery
author_rank: Super Contributor
timestamp: February 22, 2025, 10:56:08 pm
content: Agreed - the magnetic field is concentrated very close to the surface because the central pole is surrounded by a ring of the opposite magnetic pole.
Electromagnet power consumption - Page 1
Forum section: electronics / beginners

author: camelec
author_rank: Newbie
timestamp: July 10, 2021, 10:59:16 am
content: Hi all,This may seem like a stupid question. However, I have been working on a design that involves an electro-mechanical seven-segment display. Each segment isis driven by a coil, which from some experimentation can be triggered at 12V and draws around 220mA.Therefore my question is as these only need to be triggered for 1 msec. Would, four of these devices with all of their coils triggered require aminimum of a ((7*4)*220) = 6.16A power supply? I've seen otherwhich I would guess would not pull this much current if scaled up. However, I may be totally wrong here.I have also attached the datasheet for extra information.Thank you.

author: Siwastaja
author_rank: Super Contributor
timestamp: July 10, 2021, 11:25:14 am
content: If a 1ms pulse is enough to change the state, do not change all the states at the same time. If you have 7*4=28 segments, driving them all sequentially at 1ms intervals would still allow changing all the segments within just 28ms, so the sequence would be just barely noticeable to human eye. If it needs to look instantaneous, maybe drive a few at once, still a significant reduction in peak current compared to driving them all within 1ms. Anything within 10ms looks instantaneous to most people.This way, peak current is reduced and power supply is much easier to source, also voltage drops, inductive kicks from stray inductance and EMI are all reduced.

author: camelec
author_rank: Newbie
timestamp: July 10, 2021, 12:00:36 pm
content: Thanks for the quick reply! This definitely seems like the most sensible way.Cheers.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: July 10, 2021, 01:03:01 pm
content: The datasheets specifies a minimum coil voltage of 16V (19V nominal) and a minimum current of 355mA.So at 12V I would expect the display would not work reliably.You may have a batch of "good" displays, and your next batch may be "worse".Maybe the display does not work when it gets hot (sunshine on black, which it needs to be guarded from).Higher temperature is higher resistance of the copper in the coils, which translates to less current.Maybe it reduces just lifetime, as the mechanism may get a bit sloppy due to wear.Maybe some other reason.It's not smart to ignore the values from the datasheet.
Electromagnet simulation shows large force in FEMM - Page 1
Forum section: electronics / beginners

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: October 07, 2018, 09:38:18 pm
content: I am trying to simulate a simple magnetic circuit in FEMM.But I can't for my life figure out why I'm getting large attraction force of 300N on the left object.I am using the (Force via weighted tensor option)I have powered the coil with MMF of 100AT, and the magnetic material is Electrical steel.I have attached the file here.Thanks in advance.

author: _Wim_
author_rank: Super Contributor
timestamp: October 08, 2018, 07:28:35 pm
content: I think you better post this one on the FEMM yahoo group, as I do not think this is a commonly used package here.https://groups.yahoo.com/neo/groups/femm/info

author: ZeroResistance
author_rank: Frequent Contributor
timestamp: October 09, 2018, 09:51:56 am
content: Yes I guess I'll do that, thanks for the link.
electromagnetic flow meter - Page 1
Forum section: electronics / beginners

author: deepakdange
author_rank: Newbie
timestamp: May 23, 2018, 02:57:02 am
content: i have developed 1.5" electromag. it works fine when straight run is there or on the mouth of pump driven by 3 phase electric motor.but when the same pump is driven by hydraulic motor i get enhanced readings. viz.pump rpm 1440 which is fix for both motors and let flow is 13.2 m3/hr on electric motor then it comes 24 m3/hr on hydraulic motor?arrangement is 2" pump, 2" 3 way valve, elbow with 1.5" reducer, electromag and almost straight run open system.

author: Vtile
author_rank: Super Contributor
timestamp: May 23, 2018, 02:31:44 pm
content: How is the motors verified to give the same RPN?How is the flow of water measured to verify your readings from the prototype?

author: deepakdange
author_rank: Newbie
timestamp: May 24, 2018, 03:06:44 am
content: there is standard calibrated rpm indicator, electromag,etc.flow is the same (which can make variable from 0 to 26 m3/hr)i am getting enhanced signal at amplifier output on hydraulic which is measured on the scope. viz.5v operating(single supply) system, reference(grounding rings, etc) at 2.5vinput preamp. INA333 with gain = 5 and standard circuit design for electromag(ref texas instruments)batching are matched within a liter measured for 25, 50, 100, 200 liters.motor electric hydrauliczero 1948/1934 1948/193413.5m3/hr 2188/ 1690 2450/1422batching25 24.6 3450 49.8 71-73100 99.2-100.6 142-160200 198-201 276-284slope gets changed but linear function.is there any physical parameter affecting the system?