hybridfree/eevblog-posts huggingface dataset:
What MOSFET can I use to replace an IRLU014N-ND??? - Page 1
Forum section: electronics / beginners

author: Reptile-Addict
author_rank: Newbie
timestamp: August 16, 2018, 06:19:44 pm
content: I have a schematic which uses an IRLU014N MOSFET (https://www.digikey.com/product-detail/en/infineon-technologies/IRLU014N/IRLU014N-ND/446574) but that type is obsolete and I'm having trouble finding a replacement.Maybe I'm thinking too difficult, I'm an mechanical engineer that likes to tinker with electronics but by far no electroncs expert.Can someone explain to me what I need to keep in mind while looking for a replacement?Thanks in advance.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 16, 2018, 08:56:09 pm
content: 1. Go up to the product category to get a new selection of MOSFETs.2. Tick "In Stock"3. Select Packaging: Cut Tape, Bulk or Tube4. Technology and FET Type: MOSFET, N-channel5. Supplier Device Package: I-PAK / TO-251 (find and select all equivalents)6. Vdss >= 50V (select all options or enter value in the Min box)7. Rds On <= 150 mohm (ditto)8. Gate Charge (Qg) within +/- 30% of original value (7.9nC)9. Vgs(th) ditto (1V)10. Sort by price, lowest to highest. Find a reasonably stocked part with similar parameters. If you're just replacing things, stock probably doesn't matter to you. If you're substituting a BOM item, probably find one that stocks well at DK and others (maybe use Octopart or other supply aggregator to check?).Power dissipation, pinout and other features probably don't matter: IPAKs aren't usually heatsinked, so the power dissipation rating will not be reachable anyway, and pinouts are always consistent (but, hey, do check the datasheets to make sure). Brand and series probably don't matter much, either; DK stocks quality brands.Tim

author: Reptile-Addict
author_rank: Newbie
timestamp: August 18, 2018, 06:29:31 pm
content: Thanks!!!!
What MOSFET to use? - Page 1
Forum section: electronics / beginners

author: xorgmc
author_rank: Newbie
timestamp: September 25, 2016, 11:46:15 am
content: Hi,I'm trying to build a LED fairy lights running from a Li-Ion battery (which is charged by a solar cell) with a timer (press a button and the LEDs turn on for about 3h). I want to do it completely analog with a capacitor and "a kind of transistor". First I tried using 2 BJTs in a darlington pair, but it didn't work out really good because either the Collector-Emitter resistance was too high (I guess) and the LEDs weren't bright enough when turning the timer on, or the Collector-Emitter resistance was too low and the LEDs were glowing when the timer was turned off (1mA is not a really good stand-by current on a battery). So a relative told me to use a MOSFET which sounded quite a good idea to me as it isn't controlled by current. But the amount of things that seem important when choosing one seem just massive to meThe operating voltage is of course about 4.2V - 3.3V, and the LED string lights nicely at about 200mA (40 leds in parallel - 5mA per LED) - I got that with a 3.3 Ohms resistor before the leds.I thought about a circuit similar to this:http://2.bp.blogspot.com/-U_YWj3oGLgs/Ty3ByRJ7cLI/AAAAAAAAAE4/w106YZFBpwE/s1600/off-after-delay-switch-by-mosfet.jpgCan anyone recommend a MOSFET that is suitable for such applications? Or should I use a completely different method?

author: bobaruni
author_rank: Regular Contributor
timestamp: September 25, 2016, 12:25:41 pm
content: It could work OK using that method.You will need a low gate-source threshold voltage VGS N-CH MOSFET and preferably one with reasonable drain-source on resistance RDS(on).Keep in mind that as the capacitor discharges, the LEDs will eventually dim and the MOSFET will eventually start to dissipate some heat as the drain-source resistance increases as the channel is no longer saturated.

author: xorgmc
author_rank: Newbie
timestamp: September 25, 2016, 12:44:35 pm
content: Quote from: bobaruni on September 25, 2016, 12:25:41 pmLike this?http://www.produktinfo.conrad.com/datenblaetter/550000-574999/563625-da-01-en-MOSFET_N_KA_100V_32_ZVNL110A_TO_92_3_DIN.pdfIs there a formular to calculate the drain current at a given voltage?

author: xorgmc
author_rank: Newbie
timestamp: September 25, 2016, 04:32:32 pm
content: Or is a TN0604 better? (http://ww1.microchip.com/downloads/en/DeviceDoc/TN0604%20D080813.pdf)

author: Chalcogenide
author_rank: Regular Contributor
timestamp: September 25, 2016, 08:22:25 pm
content: Take a look at the AO3400. It's logic level rated and can handle a couple of amps of current with <50mOhm RDSon. Super-cheap and small (maybe too small if you are new with soldering).
What Name of This Mini LCD? - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 14, 2015, 05:46:15 am
content: i try to find this in ebay but "mini lcd" didnt turn up anything like it.. you can find this screen used in vape watt adjustable mod such as ipv d2 or subox. the size is small around 21mm x 7mm. i roughly counted the dot matrix its around 80x20 pixels. the matrix count is not that important as long as its somewhere close esp the small size of the screen. whats the name of this or where i can get it? thanks.

author: RoadRunner
author_rank: Frequent Contributor
timestamp: October 14, 2015, 06:03:07 am
content: it seems to be really small LCD ,hard to find low quantity.these small OLED may work .https://www.adafruit.com/products/661i have really small form factor

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 14, 2015, 06:36:58 am
content: i saw a picture from a member in a thread, that maybe workable...fromhttps://www.eevblog.com/forum/beginners/what-are-the-pads-on-the-sides-of-prototyping-board-for/msg775529/#msg775529Quote from: Gaurav on October 14, 2015, 06:03:07 amyes yes that is workable as well, close enough, and i believe thats it.. thanks.. i'll search in ebayQuoteeureka! with the right keyword it turn up at an instant! thanks gaurav...http://www.ebay.com.my/itm/Duinopeak-Monochrome-128x32-SPI-OLED-graphic-display-/281804765172?hash=item419cdf77f4http://www.ebay.com.my/itm/I2C-0-91-128x32-Monochrome-OLED-display-module-compatible-Arduino-/161173737381?hash=item2586b40fa5

author: RoadRunner
author_rank: Frequent Contributor
timestamp: October 14, 2015, 06:37:52 am
content: Quote from: Gaurav on October 14, 2015, 06:03:07 amif you application is low power , and has long stand by time with display all time on, thenBe aware , OLED cnsume way more current than a LCD , like few mA(~10mA or less maybe ) , depending on screen brightness. LCD without backlit may have few hundred micro Amps.you can switch of LCD backlit to save power during sleep or stand by you can still se LCD with environment light , but if you put OLED standby you will see nothing , all you can do is decrease brightness to save some power

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 14, 2015, 07:30:29 am
content: thats how they do it i guess. anything display+low power is a no no, so simply they shut down everything even the mcu goes to sleep mode except interrupts... all day lcd/oled ON usually indicates abundant power source, not low power critical application...
What notation to use when Calculating SNR using voltages? - Page 1
Forum section: electronics / beginners

author: cvriv
author_rank: Frequent Contributor
timestamp: April 17, 2019, 07:43:35 am
content: Is it just db or or is it dBV? I think it's just dB, but if that's the case, how does one know what it is, or does it not matter?

author: cvriv
author_rank: Frequent Contributor
timestamp: April 17, 2019, 09:10:33 am
content: Thanks
What OPamp to use? - Page 1
Forum section: electronics / beginners

author: IvoS
author_rank: Frequent Contributor
timestamp: December 16, 2012, 05:34:12 pm
content: I have MC33272 OPamphttp://www.onsemi.com/pub_link/Collateral/MC33272A-D.PDFI was thinking that when given the relatively low input offset around 0.1mV I would be able to have the output voltage at 0V or close to 0V (few mV) when positive pin is either grounded or connected to ground through a 10k resistor lets say. When I short both + and - input pins together or connect the positive pin to ground as I wrote, I still have 0.154V on the output. Question: Is there a way to have the output voltage close to 0 V with this OPamp? If not, what other OPamp should I be looking at? I was using single +12VDC supply to power this OPamp chip.

author: w2aew
author_rank: Super Contributor
timestamp: December 16, 2012, 07:39:12 pm
content: The output voltage of 154mV really doesn't have anything to do with the input offset voltage. It is due to the fact that your are using it in a single supply application, and the output stage can't get closer than that to the negative rail. The specs say that the output will be 200mV or less in a 5V single supply application with a 2K load. You're stuck with the saturation voltage of the lower NPN output device, can't get closer to the negative rail than that. If you want to get closer to GND, you'll have to use a negative supply rail that is below ground.

author: SeanB
author_rank: Super Contributor
timestamp: December 16, 2012, 07:50:04 pm
content: You need an opamp that is true rail to rail on both input and output. The old LM324 can do ground on the inputs( actually it will go to -0.6V happily, but caveat emptor there), and will get close to ground if you use a pull down resistor on the output to actively pull it down( it then has an output stage that runs happily in class A as a current source). Will not go to 0V exactly, but will do well depending on the load. otherwise you do need a negative supply, anything more than about 2V will do, as the internal transistors need some voltage across them.

author: IvoS
author_rank: Frequent Contributor
timestamp: December 16, 2012, 08:25:30 pm
content: OK, thanks guys.

author: IvoS
author_rank: Frequent Contributor
timestamp: December 16, 2012, 10:00:31 pm
content: WowThe actual MC33272 I was tested was defective. It's a dual OP amp, the second amp. pins 5,6,7 didn't work properly, couldn't make a comparator of it. What are the chances you buy 2 chips and one of them is faulty?... Mouser was the supplier here.
What opamp? - Page 1
Forum section: electronics / beginners

author: VitalisP
author_rank: Newbie
timestamp: January 22, 2023, 02:46:51 pm
content: Hi there,I was given an AK4390 based DAC by my friend. Unfortunately the DAC came without opamps in the output stage. Can someone help me to determine what opamp this circuit is best suited for?Many thanks!

author: magic
author_rank: Super Contributor
timestamp: January 22, 2023, 03:59:16 pm
content: Dunno, I suppose some NE5532 would be a common choice here. The datasheet shows an example filter with a few NJM5534 chips, that's JRC's version of NE5534 which was a single channel predecessor of the 5532.If you have a board with empty sockets, simply look up the name of this DAC and it shouldn't be hard to find what was originally in there.The first and most important consideration is whether they were single or dual opamps, because if you insert a wrong type it may end with magic smoke somewhere.

author: Kleinstein
author_rank: Super Contributor
timestamp: January 22, 2023, 06:09:03 pm
content: The labels of U1A and U1B suggest a dual OP-amp, like the NE5532. There are also a similar RC/NJM4560 or 4580 with similar parameters.

author: Zero999
author_rank: Super Contributor
timestamp: January 22, 2023, 06:45:01 pm
content: Nothing special is required. The TL072 would probably also work, but the NE5532 is better suited to the lower impedances used.

author: magic
author_rank: Super Contributor
timestamp: January 22, 2023, 08:08:02 pm
content: These days 5532 is so cheap that it's no brainer for any audio application that can take it.You probably wouldn't even save much going with JRC chips anymore.TL072 is only good where JFET is necessary and you don't need or can't afford anything better.This means being prepared to live with phase reversal, poor load driving, input capacitance modulation, ...Just stay away from NE5532 from auction sites and small hobby stores which supply themselves from auction sites.These chips are at best recycled, or otherwise rebranded RC4558, if not LM358

author: Zero999
author_rank: Super Contributor
timestamp: January 22, 2023, 09:40:59 pm
content: Quote from: magic on January 22, 2023, 08:08:02 pmHeck even either of those might do. It depends on how it's used. Add a pull-up/down resistor to the LM358's output to get rid of the crossover distortion.

author: magic
author_rank: Super Contributor
timestamp: January 22, 2023, 09:47:27 pm
content: No, they are crap. I hate RC45-anything ever since I found +10V on the output of my O2 headphone amp after swapping a completely noncritical MOSFET for a different type with similar specs.Never again touch anything with phase reversal in it(And distrust homebrew power sequencing solutions...)Besides, these things have much more noise, distortion, everything you could possibly not want.With LM358 you can actually hear the noise by plugging sensitive headphones to the output, even at unity gainJust say no. In audio, don't look for reasons to use NE5532. Look for good justification if choosing anything else.
What options do I have for a small switch in the middle of 22-24AWG wire? - Page 1
Forum section: electronics / beginners

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: September 05, 2023, 12:54:31 am
content: I am working on a project that will have me make an adapter cable using 22 to 24AWG wire, and I now realized that one of the wires I might want to be able to disable when I need to. I figured the easiest way to do this would be to put a switch in the middle of the wire. Just a simple rocker or toggle or so switch. Only problem is that most of these switches are somewhat large, others are also pushbutton which I don't need or have more than two leads. Are there any types of switches one can recommend that are just a very simple and basic on/off switch that would be better to put in the middle of a 22-24AWG wire that are small and would take up as little space as possible?

author: BillyO
author_rank: Super Contributor
timestamp: September 05, 2023, 01:02:04 am
content: https://www.digikey.ca/en/products/detail/adafruit-industries-llc/3064/6022074

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: September 05, 2023, 02:36:32 am
content: Wanted one that's more of a switch, not a button. And I just need to cut off a single signal wire.

author: BillyO
author_rank: Super Contributor
timestamp: September 05, 2023, 02:38:49 am
content: Did you read the datasheet? It is an on/off switch. Not just a momentary button.

author: themadhippy
author_rank: Super Contributor
timestamp: September 05, 2023, 02:43:58 am
content: option z ,put a single pole plug n socket on the wire

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: September 05, 2023, 03:56:43 am
content: Quote from: BillyO on September 05, 2023, 02:38:49 amYeah but a button wouldn't be obvious what position it's in, also it has two wire leads.Quote from: themadhippy on September 05, 2023, 02:43:58 amI don't want a disconnected wire just floating around in there though.

author: amyk
author_rank: Super Contributor
timestamp: September 05, 2023, 04:23:41 am
content: Look for "micro slide switch".

author: Cyber Akuma
author_rank: Regular Contributor
timestamp: September 05, 2023, 04:28:49 am
content: Quote from: amyk on September 05, 2023, 04:23:41 amHmm, these look like the closest kind of thing I might be able to make use of if I put heat shrink tubing around them.
What parameters are important when picking a relay? - Page 1
Forum section: electronics / beginners

author: LoveLaika
author_rank: Frequent Contributor
timestamp: June 10, 2021, 09:47:46 pm
content: I found a video about using a relay to function as a soft-starter to limit in-rush current. However, looking at the parts on Digikey, I don't know how to pick out a good relay. What parameters should I look at when picking a relay? Also, with regards to the circuit in the link below, how would one use it alongside a NTC thermistor to better limit the in-rush current?https://www.instructables.com/How-to-Make-a-Softstarter/

author: BeBuLamar
author_rank: Super Contributor
timestamp: June 10, 2021, 10:53:05 pm
content: The function of the relay is to bypass the resistor when it switches to full power. So the voltage and current rating must be sufficient for the circuit in running condition. Some what higher is desirable. The coil voltage must match the voltage you have in this case 12V should be fine. The actual voltage would be a bit less but not by much.

author: LoveLaika
author_rank: Frequent Contributor
timestamp: June 11, 2021, 01:28:30 am
content: Thanks for the reply. Yeah, the power resistor 'reduces' the current down to a safe level, and when the MOSFETs turn on, the relay turns on and bypasses the resistor, which all depends on the RC values. Let me see if I kind of understand.Let's use the example relay below. One thing to note is that my input voltage is 15-20 volts rather than 12 volts. So, looking at the coil voltage rating of 12 volts, from my knowledge, any voltage from my 15-20 volt range will turn it on without a doubt (max 30 volts). The coil itself, assuming like the schematic and no other resistors in series with the coil, will draw 37.5 mA (the coil current and coil resistance). When the switch closes, the contacts can pass a maximum of 10 amps. That's pretty much all I'm getting from what I understand. Is this correct? In this case, this relay would work in the schematic that I referenced.https://forum.digikey.com/t/understanding-relay-coil-voltage-specifications/946https://www.digikey.com/en/products/detail/te-connectivity-potter-brumfield-relays/OJE-SS-112HMF-F000/1427487
What part do i order? - Page 1
Forum section: electronics / beginners

author: brian-kc0kfg
author_rank: Newbie
timestamp: June 23, 2016, 03:36:40 pm
content: Hello all my first thought when needung help with this was here, so here we go.My outdated mig welder had a pot die on it, pulled the numbers and have ordered a new one.As i was looking in there saw a resistor that is clearly cooked, but what size do i use?I think i see a 5 under the burn.Here i will ahow you what i see.https://youtu.be/U19mQ4odBno

author: singapol
author_rank: Frequent Contributor
timestamp: June 23, 2016, 04:58:30 pm
content: It looks like a 5 watter from the proportions but do you know the resistance value?

author: MosherIV
author_rank: Super Contributor
timestamp: June 23, 2016, 05:03:43 pm
content: HiTry measuring it.Those wire wound potted high power resistor are able to run well beyond their power ratting, they can even start to glow red.They usually recover when powered off and left to cool down.Try getting a 10Watt replacement, just in case.

author: brian-kc0kfg
author_rank: Newbie
timestamp: June 23, 2016, 05:19:53 pm
content: Ok i shal, after all other than wire speed control it was working fine.If I do replace it will i be ok if its not spot on the righr size?

author: uncle_bob
author_rank: Unknown
timestamp: June 24, 2016, 12:49:25 am
content: Quote from: brian-kc0kfg on June 23, 2016, 05:19:53 pmHiIf you go to the trouble of replacing it, put in a part with the same resistance, but twice the power rating.Bob
What PCB Cleaner to use ? - Page 1
Forum section: electronics / beginners

author: Albert101
author_rank: Newbie
timestamp: March 12, 2013, 05:29:54 am
content: Hello,I need to do a repair to a PCB for my dishwasher and the side that is soldered seems to be covered by some sort of varnish or painted translucent plastic.What is this coating and how do I remove it in order to desolder a relay that needs to be changed ?Thank you for your help.

author: ddavidebor
author_rank: Super Contributor
timestamp: March 12, 2013, 06:14:02 am
content: You should only take off a few millimeters with a screwdriver so you can make contact with the tip.

author: Psi
author_rank: Super Contributor
timestamp: March 12, 2013, 06:32:55 am
content: It's most likely conformal coating to protect the circuit from the corrosive effects of the steam which contains dissolved washing powder.

author: Albert101
author_rank: Newbie
timestamp: March 12, 2013, 07:22:37 am
content: And I should reapply some conformal coating after my repair is done correct ?Thanks so much for the info.

author: moemoe
author_rank: Regular Contributor
timestamp: March 12, 2013, 11:10:16 am
content: Yes, you probably should, the manufacturer didn't apply it without a reason.I myself use "Urethan 71" from Kontakt Chemie, I coated some pcbs built into my motorcycle with it (everywhere but the contact terminals), and it works pretty well:http://www.crcind.com/csp/web/ProdDisp.csp?lng=3&idx=2827553&country=GE&product=URETHAN%2071&business=ELECTRONIC&CSPCHD=00000001000034uziMS6DB0000I5uvOzre8o9Mub7hDdgS1w--Just found this funny video when looking for an english page of the manufacturer:

author: ConKbot
author_rank: Super Contributor
timestamp: March 12, 2013, 11:26:11 am
content: Depending on how thick/heavy the material was, I'd go for using a soldering iron tip that wasnt my favorite, and doing it in a well ventilated place, and forget about even removing the coating. once you desolder it, you can scrape off the crispy bits, clean up your joint, replace the relay. Seal it back up something when youre done. Silicone would keep water off, but is still permeable to water vapor. Something like marine goop would be commonly available, and keep water vapor out, but it certainly wouldnt be the prettiest repair.
What pcb manufacturer should I use - Page 1
Forum section: electronics / beginners

author: Tom10000
author_rank: Contributor
timestamp: May 29, 2017, 09:20:59 pm
content: Hello,I am a 12 year old in Sydney Australia I have been working on a few different pubs in altium circuit studio but I can't find a pcb manufacturer that is cheap. Please could you recommend one thank you.From Tom10000

author: Dave
author_rank: Super Contributor
timestamp: May 29, 2017, 10:29:07 pm
content: I'm not sure what cheap means for you, but you could take a look atPCBshopper, put the relevant information into the form and it will check the prices among the lower cost Chinese manufacturers for you. If you are prepared to wait a little longer for delivery, the prices tend to be quite reasonable for a hobbyist budget.

author: Muttley Snickers
author_rank: Unknown
timestamp: May 30, 2017, 12:50:36 am
content: The answer to your question may already be in this thread linked below.https://www.eevblog.com/forum/manufacture/what-pcb-should-i-use-manufacture/

author: MechEng87
author_rank: Contributor
timestamp: June 01, 2017, 07:16:23 am
content: i have used seeed studio's fusion PBC service several times with great results and the boards are quite inexpensive. for a minimum of 5 or 10 boards(100x100mm) max its only around 10.00 USD and depending on the shipping options you choose its only $10 - $18 more and around 2-3 weeks time to get your boards.
What pin gets hot? MIC5219 SOT-23-5 - Page 1
Forum section: electronics / beginners

author: Bootalito
author_rank: Unknown
timestamp: May 31, 2018, 12:51:24 pm
content: I'm designing a PCB for a reflow oven (https://easyeda.com/terryjmyers/ESPReflow). I'm using a MAX31856 thermocouple amplifier and powering the analog power pin from a low noise LDO (MIC-5219 sot-23-5 packagehttp://www.mouser.com/ds/2/268/mic5219-779135.pdf). I want to do a small top layer pour underneath the LDO to dissipate heat (mainly away from the MAX31856). What pin should I connect it to? I also realize that the MAX31856 will not draw very much power, therefore the LDO will not get that hot, but I still want to do a thorough design.The sot-23-5 package doesn't have a thermal pad. On the packages that do, its connected to GND. Also, there are packages with multiple GND pins, presumably for heat dissipation. Is it save to assume the GND pin on the SOT-23-5 will be the pin that gets hot?TLDR: Is it safe to assume that the GND pin of the sot-23-5 package of a mic2519 LDO is the one I should connect to a PCB heatsink, based on the other packages having more GND pins or exposed thermal pads connected to GND?

author: Howardlong
author_rank: Super Contributor
timestamp: May 31, 2018, 02:34:03 pm
content: Ground pin is a good start, and sneaking in a few closely packed vias to the other side of the board and any multilayer ground plane is a good plan. There’s also no harm in using wider tracks elsewhere, but ground is a good start, and it’s often flood filled anyway on the board and is typically the die’s substrate.

author: Zero999
author_rank: Super Contributor
timestamp: May 31, 2018, 03:09:59 pm
content: I'd say the ground pin, given that the packages with a thermal pad connect it to ground.
What plug is this ? - Page 1
Forum section: electronics / beginners

author: bingo600
author_rank: Super Contributor
timestamp: April 14, 2025, 08:25:42 am
content: I have an IVT (2011) Heatpump , and need to "steal some 5v" for an ESP WiFi IR transmitter.I found out that there is 5v on the unused flash-plug (pics)Pin1 - +5vPin8 - GNDDoes anyone have an idea what plug this is (could be) ??Unfortunately i didn't measure the pin spacing , not easy.But i measured the width of the plug (outer plastic edge) : it is 17..18 mmI might be able to use some- 2mm DupontBut a plug could be nice too...TIABingo

author: Zipdox
author_rank: Regular Contributor
timestamp: April 14, 2025, 02:05:37 pm
content: Looks like a bog-standard JST PH connector.

author: squadchannel
author_rank: Frequent Contributor
timestamp: April 14, 2025, 02:17:12 pm
content: yep, 99.99 percent jst ph.

author: bingo600
author_rank: Super Contributor
timestamp: April 14, 2025, 02:27:39 pm
content: Thank you guyzI'll look that up
What type of power supply to use for HLW8012 Energy Monitor - Page 1
Forum section: electronics / beginners

author: Eldi4
author_rank: Contributor
timestamp: August 21, 2020, 06:57:11 am
content: Hello there, i've been puzzled on what power supply to use for HLW8012 which is single phase energy monitor, it must connected to AC Grid Line directly to measure the RMS Voltage,Current, and Power. So it was impossible for the IC to get isolated from AC Line.The HLW8012 will interface to my MCU with PC817 optocoupler, because the output frequency is not that high, probably just 10kHz max and because my MCU was powered with isolated power supply.So i've been puzzled on the power supply to use for HLW8012, should i use transformerless power supply or normal SMPS?.Because SMPS is isolated, powering HLW8012 will make it looped to AC Line once again, is it okay to do so?.Or should i use transformerless power supply instead?.For me, the cost for both solution (smps or transformerless) is the same, im about to use SMPS but not sure what would happen if the load is not isolated from AC Line.
What precautions should I take while using an Oscilloscope? - Page 1
Forum section: electronics / beginners

author: Tanmay Jambavlikar
author_rank: Newbie
timestamp: February 20, 2018, 11:28:55 am
content: I have recently bought a Hantek DSO5102p for educational purposes. Although I know some basic operation of an Oscilloscope, I would like to know what all errors I can make and should be avoided as a beginner using it.

author: Jwillis
author_rank: Super Contributor
timestamp: February 20, 2018, 11:38:50 am
content: Its been posted many times before but that Dave guy has a really good video on that.Check out his other videos on oscilloscopes and much much more.

author: danadak
author_rank: Super Contributor
timestamp: February 20, 2018, 11:40:09 am
content: Some ref material -https://www.tek.com/document/technical-brief/floating-oscilloscope-measurements-and-operator-protectionhttp://in.tek.com/dl/3AW_19134_2_MR_Letter.pdfRegards, Dana.

author: rstofer
author_rank: Super Contributor
timestamp: February 20, 2018, 09:27:07 pm
content: Google 'using an oscilloscope'There is a Sparkfun video among others.

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 20, 2018, 09:51:45 pm
content: Don't probe the %^$&#& mains !

author: jasonbrent
author_rank: Regular Contributor
timestamp: February 21, 2018, 01:14:00 am
content: Alright, having watched that video a couple of times... and read the tektronix paper... I've got a dumb question.I'm using a rigol ds1074z... I've got a device I'm probing that has 3 ground planes.1) The first is on the AC side. It is grounded to the chassis. When probing the AC components (not the transformers, just bits on the AC side of the board), grounding my probe to chassis is correct, right?2) For each of the 2 DC areas of the board, the grounding points are less obvious, but I can find one with my DMM and continuity checks. For these components, I should have the scope probe grounded to the associated ground plane of the area of the board I'm probing, right?... or have I completely misunderstood this video and paper?-j

author: rstofer
author_rank: Super Contributor
timestamp: February 21, 2018, 03:33:49 am
content: Without seeing a schematic, it is impossible to recommend anything!Even on the low voltage side, we have no idea how the power supply works and whether it is earth referenced without a schematic.

author: jasonbrent
author_rank: Regular Contributor
timestamp: February 21, 2018, 04:22:43 am
content: Quote from: rstofer on February 21, 2018, 03:33:49 amWell, if you are game, the schematics are in the first post here:https://www.eevblog.com/forum/metrology/valhalla-2701c-schematics-100832/... mine is a variant of this that doesn't have the HV side (40V max, in theory instead of 1200V). The schematics identify a 0v and 0v(a) for the isolated and normal ground referenced parts, as best I can tell.. this is honestly my first time digging into schematics.Before probing anything with the scope, I've (with power off, unplugged..) tried to trace the ground down and verify with continuity checks before powering up...
What program to view PCB files? - Page 1
Forum section: electronics / beginners

author: WhiteFireDragon
author_rank: Regular Contributor
timestamp: June 29, 2013, 12:29:55 am
content: I'm looking for a free program to view some PCB files (gerber?) so I can get the exact location of some of the holes. I'm using a windows PC, and I've downloaded a few online (including KiCAD) but it doesn't seem to work properly.Which program should I use to just to get the drill hole locations on these PCBs? Are there any tutorials anywhere on how to use these programs or loading the files?

author: cthree
author_rank: Frequent Contributor
timestamp: June 29, 2013, 01:15:14 am
content: Is this a drills file? Have you opened it in a text editor?

author: Kremmen
author_rank: Super Contributor
timestamp: June 29, 2013, 05:29:01 am
content: There are several free gerber viewers out there. I use the commercial version of Pentalogix ViewMate but there is a free edition as well. checkwww.pentalogix.com

author: AndyC_772
author_rank: Super Contributor
timestamp: June 29, 2013, 07:46:53 am
content: GC-Prevue

author: kripton2035
author_rank: Super Contributor
timestamp: June 29, 2013, 08:30:26 am
content: I use a free online version here :http://mayhewlabs.com/3dpcb

author: Iano
author_rank: Newbie
timestamp: July 01, 2013, 04:00:56 am
content: Have a look at this site.http://www.homediystuff.com/etching-diy-pcb-printed-circuitt-boards/They have a section recommending some of the free PCB design software available.Look for "Computer Design Software Available" just down the page a bit (before the Step 1 of their PCB making guide).Lots of options....
What programmer to use on GD32F103C8T6? - Page 1
Forum section: electronics / beginners

author: obeids
author_rank: Newbie
timestamp: December 27, 2015, 07:57:54 am
content: Hi there guys.....So I am a newbie here.I know a little bit about electronics, leanrt most by experiments and through internet forums and videos. I currently work on Cars with Transponder system. So learnt pretty much about Memory chips, Eeproms and MCU chips.I have a friend who got on of these self balancing scooters which has become a craze in the recent months........ anyhow a screw inside came loose and shorted the PCB. This particular one has 2 PCB on either side which control each side wheel. This they are identical to each other. To cut story short I found that the MCU GD32F103C8T6 has developed an internal short.I found replacements being sold online at aliexpress but obviously such MCU normally have some CODE (program) programmed into it's memory to make it work the way you want it to.Now the question is that how do I copy info from the working MCU to the new one that I will buy? What programmer to use?I have the following stuff that I use on a daily bases but guess they wouldn't do this job.....Mini Pro TL866AR270X-progUPA USBReally appreciate you help

author: obeids
author_rank: Newbie
timestamp: December 27, 2015, 08:24:31 am
content: Hi thereThanks for the super speedy reply.So if I order this you are saying it should work? What software do I use or do they come with software?http://www.aliexpress.com/item/Hot-Sale-1PCS-ST-LINK-Stlink-ST-Link-V2-Mini-STM8-STM32-Simulator-Download-Programmer-Programming/32343514985.html?spm=2114.01020208.3.2.5eG637&ws_ab_test=searchweb201556_1,searchweb201644_3_79_78_77_82_80_62_81_61,searchweb201560_4

author: stmdude
author_rank: Frequent Contributor
timestamp: December 27, 2015, 09:38:22 pm
content: Yup, those programmers should work. The GD32F103s are more or less exact copies of the STM3F103s, and they're also compatible with the programming gear.Olimex have done some testing, and communicated with the manufacturer regarding the whole "chinese clone" thing.https://olimex.wordpress.com/2015/12/21/gd32f103rbt6-the-stm32-pin-to-pin-compatible-chinese-mcus-sample-test/As for software, unless you're building the software yourself, STs utilities should work just fine for programming:http://www.st.com/web/en/catalog/tools/PF258168But, as blueskull said, the chips probably have their copy-protection turned on, so I don't think you could read out the firmware from the old chip (or a similar non-shorted chip).Oh, and if you want to read out or program the chips, you need access to at least two programming pins. Are those exposed on the PCB? (SWDIO/SWCLK are the most likely names)

author: obeids
author_rank: Newbie
timestamp: December 28, 2015, 09:12:37 am
content: Hi thereThanks alot for the info.....I can access the chip easily. There are some programming pins also available.I guess it wouldn't be worth the hassle if they lockd the chip from reading it. Best would be to buy a complete new module. So it's $50 vs the $3. Well I think have to pop out the $50
What PSU I should buy? - Page 1
Forum section: electronics / beginners

author: lion
author_rank: Contributor
timestamp: October 07, 2016, 10:56:20 pm
content: Hello everyone.Can anyone recommend me a bench PSU that I can buy and where ? Im from Europe so I prefer european sellers.Range from 0-30V and 3A.Price: 150$/130€ max

author: rob77
author_rank: Super Contributor
timestamp: October 07, 2016, 11:37:55 pm
content: Quote from: lion on October 07, 2016, 10:56:20 pmand why do you have a New Zealand flag in your profile ?btw in Europe try Farnel or TMEQuote from: lion on October 07, 2016, 10:56:20 pmTME has some cheap PSUs below 100Eur in their offering:linear for 80Eur + VAThttp://www.tme.eu/gb/details/mps-3003s/one-channel-power-supplies/matrix/switchmode for 60Eur + VAThttp://www.tme.eu/gb/details/ax-3005ds/one-channel-power-supplies/axiomet/
What questions will a hired amp designer ask me. I am hiring an amp designer.  - Page 1
Forum section: electronics / beginners

author: Centripetal heterodyning
author_rank: Newbie
timestamp: May 11, 2020, 05:54:59 am
content: I have a specific waveform. I am hiring someone to build an amp. What questions is this person going to ask? For example, he will ask what power output do I want the amp to be, what frequency do I want. What is the source generator of the waveform. Will he need to know things like the fft of the waveform? The power spectrum? What further questions will he ask me?

author: Siwastaja
author_rank: Super Contributor
timestamp: May 11, 2020, 06:19:15 am
content: They are going to ask what this is for, and why.Engineers know from experience that most subproblems are actually "XY problems" (http://xyproblem.info/), and sometimes better solved ditching the whole specification ("do Y"), and see that doing Z results in X being done. Sometimes doing Y is impossible, or not resulting in X. Sometimes Y is just a suboptimal way of doing X.Or, sometimes, your specification is just the right way.But they'll ask you this, and unless there is a really good reason for secrecy, let them play designing the big picture.

author: Berni
author_rank: Super Contributor
timestamp: May 11, 2020, 06:32:18 am
content: Exactly what Siwastaja said.Tell the engineer what you want to do instead. The engineer will be able to come up with answers to those questions on his own rather than asking you.

author: Ice-Tea
author_rank: Super Contributor
timestamp: May 11, 2020, 07:37:08 am
content: All of the above. But in case the problem can not be substituted: what impedance is the amp feeding into.Accidently, if you share the 'whatfor' you may end up with a number of suggestions on how to solve your issue. For free
What regulations/certifications apply for low voltage DC power supplies in US? - Page 1
Forum section: electronics / beginners

author: Metatronic_Mods
author_rank: Contributor
timestamp: July 13, 2018, 10:42:31 pm
content: I was hoping someone could inform me regarding any regulations or required certifications for a low voltage (<=30V) DC power product to be sold in the US (or elsewhere for that matter)?More importantly, how does one even become educated in such matters in general? I just discovered this book earlier, which seems like a good place to start, but I'm wondering what the typical pathway for an electronics engineer to learn about these topics is? Thanks

author: Eka
author_rank: Regular Contributor
timestamp: July 14, 2018, 02:41:28 pm
content: I'd ask Underwriters Laboratories (UL).There are some Energy Star ratings for efficiency that must be observed for consumer and office devices.There are also some regulations on power factor.I just keep things simple for me by buying already made ones.

author: drussell
author_rank: Super Contributor
timestamp: July 15, 2018, 02:25:00 pm
content: The main reason so many lower-power-consumption items use external wall-wart power supplies instead of internal power supplies is because in most places, below (approximately 48, 50 or 60 volts, depending on locale) volts going into to the actual device, you are in a class where all your safety certifications, etc. are then only needed on the wall-wart itself, so you just use properly certified pre-made units for a given market.Your mains electrical safety is all then handled by the wall-wart so you just have to contend with EMI radiation, etc. where applicable on your actual device. As soon as you build the power supply into your device, you have to get all that stuff certified to the appropriate standards for each market you sell into.
What Resistor is this? - Page 1
Forum section: electronics / beginners

author: melotrom
author_rank: Newbie
timestamp: June 06, 2021, 01:54:48 pm
content: I got a broken Rode NT USB microphone that produces a lot of noise.I think i found the culprit, R21 seems broken. I have no clue what value that is and where to find a replacement.

author: RayRay
author_rank: Frequent Contributor
timestamp: June 06, 2021, 03:06:53 pm
content: Unfortunately, without the number that was on it, there's nothing you can do.You're gonna have to find someone who has the same mic, who'd be wlling to open it up and provide you with the number on that particular resistor. Try reaching out to this guy:Check under the video (click "show more") for his socials/website. If you'd be able to get the resistor's value, it's definitely fixable.

author: melotrom
author_rank: Newbie
timestamp: June 06, 2021, 06:47:41 pm
content: Thank you for the advice. I contacted the Youtuber.

author: Tomorokoshi
author_rank: Super Contributor
timestamp: June 07, 2021, 02:05:46 am
content: Observations:1. It has a 3.5 mm stereo monitor output for headphones.2. Those two circuits appear to be laid out very similarly.Therefore, R21 is very likely 6.2 kohms like R19.

author: tooki
author_rank: Super Contributor
timestamp: June 07, 2021, 06:53:14 pm
content: Quote from: RayRay on June 06, 2021, 03:06:53 pmFYI, several manufacturers have stopped printing values even onto larger SMD resistors.We just got a strip of Vishay 1206 resistors that came with no markings. At least Digi-Key now prints the info onto the tape itself…
what sensor is used in this video - Page 1
Forum section: electronics / beginners

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 01, 2016, 08:41:11 am
content: Below is link for video, which sensor is used here which can detect the glove/ball/hand touch?

author: Dave
author_rank: Super Contributor
timestamp: September 01, 2016, 02:33:10 pm
content: You could have an IR emitter inside and measure how much light bounces back. If the value suddenly increases, you know that something is in front of it. You could even reuse the LED that you have for lighting the whole dot as the receiver.

author: Vindhyachal.takniki
author_rank: Frequent Contributor
timestamp: September 02, 2016, 04:14:20 am
content: Will resistive touch work. Although person also hit it with glove.SO I dont know it may break? Is there any way it can be made strong enough??
What should be resistor's values? - Page 1
Forum section: electronics / beginners

author: catalyst
author_rank: Contributor
timestamp: November 01, 2017, 02:32:00 pm
content: Hello Everyone,I want to make a circuit that led strip with operating voltage is 12Vdc. But i'm confused. What should be R1,R5,R7,R9,R11,R12 resistors value? I want to get constant current that 15,41 mA with LM317. R3 and R4 is 27R. But I know that Vin that belong to LM317 has a specific value because lm317 have to do good regulation for constant current. For example, Vin-Vout>= 3V, 4V, 5V. How much voltage should be that? And which resistor value should be chosen for this?Image can be viewed in attachment.Thank you.

author: IanB
author_rank: Super Contributor
timestamp: November 01, 2017, 03:39:26 pm
content: Quote from: catalyst on November 01, 2017, 02:32:00 pmOn the diagram they are labeled as 1 ohm. They are load balancing resistors to ensure even current sharing between the parallel strings of LEDs. They just need to be a small value, the exact value is not critical.

author: catalyst
author_rank: Contributor
timestamp: November 01, 2017, 04:56:30 pm
content: Thank you so much. How big should Vin be for good current regulation? Because when I cut off the voltage to 11V, current falls down.

author: Audioguru
author_rank: Super Contributor
timestamp: November 02, 2017, 12:02:29 am
content: Quote from: catalyst on November 01, 2017, 04:56:30 pmThe datasheet for the LM317 and other voltage regulators specify the "dropout voltage" at typically 2.25V but then it has already dropped the current a little. The maximum dropout voltage for some LM317 ICs is higher than 2.25V.

author: catalyst
author_rank: Contributor
timestamp: November 02, 2017, 01:22:14 pm
content: Should I use LDO regulator such as lm1117? Because it has a low dropout voltage. You say that my circuit doesn't work, does it? When I calculate dropout voltage in my circuit, it is approximately 2.280V. It means that my Vin=3.53Volt. Because of 2.280V>2.25V, does it work regularly? By the way, temperature is very crucial for me. Does this situation affect my lm317 in terms of temperature? Sorry for my absurd questions. Thank you all.

author: catalyst
author_rank: Contributor
timestamp: November 02, 2017, 01:26:44 pm
content: And I read the drop out voltage must be approximately 3V in lm317 datasheet. If so, Is my circuit compatible with LDO regulators?

author: Zero999
author_rank: Super Contributor
timestamp: November 02, 2017, 01:34:44 pm
content: Quote from: Audioguru on November 02, 2017, 12:02:29 amThat's when it's being used as a voltage regulator. When the LM317 is used as a current regulator, then it needs an additional 1.25V of headroom, giving 3.5V.
What should be the purpose of this two reverse biased diodes + RC? - Page 1
Forum section: electronics / beginners

author: mcinque
author_rank: Unknown
timestamp: June 23, 2015, 10:06:03 pm
content: I was looking inside a Li-Po/Li-Ion/Pb/Ni-Cad RC battery charger and on the 5V rail of the LCD display I found two reverse biased 4148 and a RC circuit connected to ground.What's the purpose of those components? I'm quite ignorant, but I guess it's some kind of static/esd filtering on the 5V rail. How about that?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: June 24, 2015, 01:19:17 am
content: If they're 1N4148 as shown, nothing. Not even very good at reverse bias protection (there's two in series).Possibly helpful if zener type. Still not obvious why one might want an RCD in there.Tim

author: Shock
author_rank: Super Contributor
timestamp: June 24, 2015, 07:03:22 am
content: Is this a voltage regulator protection circuit and you have traced it out wrong?

author: mcinque
author_rank: Unknown
timestamp: June 24, 2015, 11:19:13 am
content: @teslacoil: Yes, they are 2x 1n4148 equivalent in a SMD package. Agree with you if zeners, but Definitely they are NOT that kind (checked).@Shock: Well, precisely because it's so strange, I've checked it many times with the same results. They are only 3 (4) components on a double sided pcb, I've even desoldered the components to see any hidden via or trace.

author: tszaboo
author_rank: Super Contributor
timestamp: June 24, 2015, 12:49:27 pm
content: It attenuates by a little bit if the output voltage of the regulator is more than -1,5V, obviously.Maybe it has to do something with preventing the LCD from blowing up if the gnd is not connected but the data is(guess)?