hybridfree/eevblog-posts huggingface dataset:
Is there a way to test a BGA chip before soldering? - Page 1
Forum section: electronics / beginners

author: ablacon64
author_rank: Frequent Contributor
timestamp: November 08, 2011, 10:10:41 am
content: Hi!A notebook came with a black screen, typical BGA cold solder problem. I reballed the chip, AMD RS780, and the motherboard died.After removing the chip I noticed that some capacitors on top had zero ohms resistance, is this normal (remembering that the chip is off the board)?The marked capacitors are the ones I'm talking about:So, I wonder if there a reliable way to test a BGA chip before soldering it to the board. Of course, there's no way to test the functionality, but at least test if it's shorted or not.

author: ElektroQuark
author_rank: Unknown
timestamp: November 08, 2011, 10:20:39 am
content: They are probably decoupling capacitors so it looks like you have some bridges between VDD and VSS lines.Try desoldering, reballing and soldering again the IC.

author: usreworkstationsMODS
author_rank: Newbie
timestamp: May 22, 2013, 05:59:01 am
content: Quote from: ablacon64 on November 08, 2011, 10:10:41 amHave you tried to use Multi-Meter and thermcouple ? From what that pic I am saying, you do need to clean up by desoldering, and make new one. Have you tried that?
Is there any battery simulator module that having exact battery function? - Page 1
Forum section: electronics / beginners

author: Vcky_electro
author_rank: Contributor
timestamp: February 16, 2024, 09:41:59 am
content: Hi techies.I need battery simulator/ emulator which actually act like battery.ESR settings

author: Vcky_electro
author_rank: Contributor
timestamp: February 16, 2024, 09:43:03 am
content: It should have mAh settings.And charging , discharge curve should be similar to actual battery..Is there anything available??

author: Psi
author_rank: Super Contributor
timestamp: February 16, 2024, 09:57:14 am
content: What size battery, simulating a car battery is totally different to simulating a coin cell.The correct way to do it is using a four quadrant powersupply with battery simulation mode. But that is $$$
Is there any equivalent for TP5410? - Page 1
Forum section: electronics / beginners

author: aju11
author_rank: Contributor
timestamp: February 15, 2019, 10:28:26 am
content: I am looking an equivalent replacement from well known manufacturers like TI, OnSemi, ST etc..Need not be a pin to pin match.

author: alex-sh
author_rank: Regular Contributor
timestamp: February 15, 2019, 12:47:45 pm
content: How about TPS61200?

author: karun939
author_rank: Newbie
timestamp: February 22, 2019, 11:11:38 am
content: May i know the Input and output Specific ranges?

author: thinkfat
author_rank: Unknown
timestamp: March 18, 2019, 02:40:02 pm
content: I was trying to find an equivalent chip recently, too. The closest I found is the RT9480 (Richtek). You can order it from Digikey.Compared to the TP5410 (and the functionally equivalent TP5400) it is much more expensive ($3.40 >> $0.20), but the RT9480 has a lot more built-in functionality, especially regarding protection functions.I ended up using the TP5400 (sourced from LCSC) because I needed only a few devices and didn't care for future availability.

author: thinkfat
author_rank: Unknown
timestamp: March 18, 2019, 02:42:08 pm
content: Quote from: alex-sh on February 15, 2019, 12:47:45 pmThat's only a boost converter, the TP5410 is a lipo charger / boost converter combined. You need to add an external power path though, if you want to use the output while charging.
Is there any other PC software for Siglent scope  - Page 1
Forum section: electronics / beginners

author: gigabyte091
author_rank: Contributor
timestamp: June 12, 2016, 05:54:30 pm
content: Hi guys,for past 3 days im trying to install that bloody easyscope... It is anything but easy... I installed NI VISA drivers, NET framework, i tried some files from another topic from this forum, but everytime i start program there is message easyscope has stopped working...I'm running W10 on my laptop, and i tried compability mode, and nothing...Is there any other software like easyscope, but actually working ?
Is there any practical difference between a full wave bridge vs full wave CT? - Page 1
Forum section: electronics / beginners

author: BlueBill
author_rank: Regular Contributor
timestamp: February 16, 2015, 03:10:04 am
content: Is there any practical difference between a full wave bridge vs full wave centre tap?

author: EEVblog
author_rank: Unknown
timestamp: February 16, 2015, 03:17:30 am
content: Yes, a full wave bridge has two diodes losses, a CT circuit only has one.

author: BlueBill
author_rank: Regular Contributor
timestamp: February 16, 2015, 03:25:29 am
content: Quote from: EEVblog on February 16, 2015, 03:17:30 amSo simple, thanks.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 16, 2015, 05:00:10 am
content: More than that; the FWCT incurs sqrt(2) more losses in the transformer, because only half of the secondary winding is being used at any given time, and each winding is only used half the time. Thus, you need twice the wire, but bigger than half the wire size -- because 50% duty cycle means 71% RMS current.Tim

author: BlueBill
author_rank: Regular Contributor
timestamp: February 16, 2015, 05:07:24 am
content: Hmm, so to get the most out of a small transformer like the one below would be full bridge not CT?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 16, 2015, 08:56:09 am
content: Yes. And the two diode drops of a FWB aren't a big hit if it's more than a moderate voltage (over 10 or 20V, say).And for lower voltages (20V and below, say), you can use schottky diodes, which lessens the blow of a FWB, so it's not terrible down to, say, 5V or so.And if you have to have still better efficiency than that, line frequency transformers simply aren't what you need anyway.Tim

author: BlueBill
author_rank: Regular Contributor
timestamp: February 16, 2015, 03:42:39 pm
content: Thanks, it's been so long since I worried about DIY power supplies I forgot the basics.Q: is there a difference between 2x 6.3VAC secondaries wired in series vs 2x 12.6VAC in parallel?

author: zapta
author_rank: Super Contributor
timestamp: February 16, 2015, 04:08:42 pm
content: With the parallel pay attention to phase. Otherwise it's like connecting two batteries in opposite polarity.
Is there any reason not to use a thermistor in a reflow oven? - Page 1
Forum section: electronics / beginners

author: Mechanical Menace
author_rank: Super Contributor
timestamp: February 20, 2015, 08:42:23 pm
content: Well I already have a few highish temp thermistors around and want to get a reflow oven at least working for when my first batch of PCBs arrives from Beta Layout. I've seen a few examples of people doing this and they always seem to use thermocouples so I was wandering if there's a reason not to use a thermistor?Thanks

author: Simon
author_rank: Unknown
timestamp: February 20, 2015, 08:49:10 pm
content: At those temperatures you might need to double check that your thermistor can cope. They generally do not do more than 150°C where as thermocouples can go up to 1000°C.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: February 20, 2015, 09:02:37 pm
content: What would you solder it with?

author: wraper
author_rank: Unknown
timestamp: February 20, 2015, 09:03:22 pm
content: At such temperatures RTD (PT100, PT1000) usually is the best (most accurate) choice. However they cost more than cheap K type thermocouples.

author: jamesd168
author_rank: Contributor
timestamp: February 20, 2015, 09:26:34 pm
content: Quote from: Mechanical Menace on February 20, 2015, 08:42:23 pmI guess it depends on exact temperature you want to use it for. the oven should tell you what is the highest temperature it will go up to, and your thermistor should also have a temperature rating.

author: Simon
author_rank: Unknown
timestamp: February 20, 2015, 09:27:49 pm
content: NTC's also have very poor resolution at high temperatures as the curve becomes flatter and flatter.

author: Mechanical Menace
author_rank: Super Contributor
timestamp: February 21, 2015, 03:25:56 pm
content: The thermistors I have were meant for a RepRap hotend so are meant to be able to handle 300 degrees.Quote from: mikeselectricstuff on February 20, 2015, 09:02:37 pmWouldn't crimps be OK? Honest question btw.Quote from: Simon on February 20, 2015, 09:27:49 pmThis is just a "for now" solution unless it works well and not just well enough.Thanks everybody.

author: Edwin G. Pettis
author_rank: Frequent Contributor
timestamp: February 21, 2015, 04:16:33 pm
content: While thermistors are rated up to ~150°C, they are only stable, long term, up to 100°C, above that, use should be only intermittent. Platinum RTDs, particularly the thin film types are accurate and can be found for under $5 and they do require an amplifier stage. Thermocouples are relatively cheap but require a compensation junction plus amplifier to work as their microvolt output signals are much too low to work with otherwise. Unless you require very accurate measurement, the RTD interface amplifier can be relatively simple to implement and an RTD has a much higher change per degree than a thermocouple.
Is there any relation between DDR- CLK and DQS - Page 1
Forum section: electronics / beginners

author: muthukural001
author_rank: Regular Contributor
timestamp: February 15, 2021, 01:48:09 pm
content: Hi All,I have a basic question that DDR CLK which is being used for ADDR/CMD transfers and DQS which is being used for Data read/write to and from DDR have any relationship (Or) both are indpendent ?. Because, I have read that DDR memory samples ADDR/CMD line on CLK rising/falling edges, and DQ lines on DQS rising/falling edges.Also, does both CLK and DQS switching at same frequency ?. For example, if you take DDR4 -3200 MTS, both CLK and DQS frequency is 1600MHz though both are independent?. Can anyone clarify my doubt?Thanks and Regards,Muthu
Is there any risk of having the wrong fuse installed in your digital multimeter? - Page 1
Forum section: electronics / beginners

author: Decoman
author_rank: Regular Contributor
timestamp: December 07, 2017, 10:09:37 am
content: So having ordered a digital multimeter off eBay, I am wondering if maybe i should go buy some extra fuses, just in case I would need them.And now I am wondering, is there any risk of me installing the wrong fuses in my digital multimeter should there come a time I replace them?The reason I am asking is that I can at least envision that I go buy some branded fuses that aren't the same brand as the ones that were installed.For my DMM (Uni-T UT61e), I would think that I would required 10A and 1A fuses, but that the brand name would be unimportant as long as the fuses are of good quality.Also, I am thinking that the very size of the fuses will vary with its rated specs and thus I can imagine that this might make it basically impossible to ever insert the wrong type of fuse, and if maybe there are standards for fuses, there ought not be possible ever get this wrong.

author: Mr. Scram
author_rank: Super Contributor
timestamp: December 07, 2017, 10:19:29 am
content: You sometimes have slow and fast blow fuses that are dimensionally the same, but will act differently.
QWERTY - Page 1
Forum section: electronics / beginners

author: pranav
author_rank: Contributor
timestamp: April 23, 2017, 04:18:11 pm
content: ...

author: mfratus2001
author_rank: Contributor
timestamp: April 23, 2017, 04:39:09 pm
content: No.If you can't hear the frequency, it is over 10KHz. But you can make some instruments.Frequency is in the time domain, so "spark versus time" is what you are measuring. Dragging the wire that draws a spark across metal covered with paper will leave a dotted line of holes on the paper. It may be hard to move fast enough if the frequency is very high.

author: pranav
author_rank: Contributor
timestamp: April 27, 2017, 04:43:59 am
content: Quote from: mfratus2001 on April 23, 2017, 04:39:09 pmNo, the paper just simply burns. It is AC continous output.Sent from my Lenovo S850 using Tapatalk

author: george.b
author_rank: Frequent Contributor
timestamp: April 27, 2017, 08:57:02 am
content: Why, yes, it's very simple:Stick the flyback output onto your tongue;Count how many pretty flashes you see in a second.Actually, no,don'tdo that. Why don't you show us the circuit you used? That might give a better ballpark figure than "guessing".

author: Zero999
author_rank: Super Contributor
timestamp: April 27, 2017, 09:17:54 am
content: How are you driving the flyback transformer?If it's driven from an RC oscillator such as a 555 timer, then the frequency can be easily calculated.If it's driven using a blocking oscillator, or Mazilli driver then it's more difficult to predict, since it depends on the characteristics of the transformer and the load connected to it.

author: Ian.M
author_rank: Super Contributor
timestamp: April 29, 2017, 11:24:16 am
content: Its not particularly difficult to build a crude frequency meter. Either use a MCU with an externally clocked counter timer, or build a frequency to voltage converter to use with a multimeter. Calibrate over the audio range with a tone generator program and a PC soundcard, and for higher frequencies, the easiest option is to spot-check using crystal oscillator modules.

author: james_s
author_rank: Super Contributor
timestamp: April 30, 2017, 06:44:24 am
content: Or buy a frequency counter, even something like this is going to be better than guessing and it's hard to get much cheaper.http://www.ebay.com/itm/Frequency-Counter-Meter-1Hz-50MHz-for-Crystal-Oscillator-Digital-LED-DIY-Kits-/141640365757?Even real instruments can be had for relatively little, something like this for example.http://www.ebay.com/itm/HEWLET-PACKARD-80MHz-FREQUENCY-COUNTER-5381A-serial-1404A00956-/302297579145?

author: danadak
author_rank: Super Contributor
timestamp: April 30, 2017, 09:43:10 am
content: Depending on frequency you could use sound card software, to eitherimplement a counter or look at spectrum plot.Make sure you protect sound card input, google "sound card input protection"to find solutions.http://techmind.org/audio/https://www.zeitnitz.eu/scope_enRegards, Dana.
Is there anyone can hack atsha204 - Page 1
Forum section: electronics / beginners

author: rzwys
author_rank: Newbie
timestamp: August 11, 2014, 09:03:29 am
content: I have interest in hacking atsha204?I have read the datasheet and can capture the waveforms between communication about the chip and host, but I still have no idea about how to do it

author: jeremy
author_rank: Super Contributor
timestamp: August 11, 2014, 09:37:06 am
content: no

author: amyk
author_rank: Super Contributor
timestamp: August 11, 2014, 10:22:05 am
content: Pay the Chinese to decap and analyse one for you...
Is there away to check continuity over long distances? - Page 1
Forum section: electronics / beginners

author: Beamin
author_rank: Super Contributor
timestamp: February 15, 2020, 10:56:56 am
content: Say you wanted to check to see if the gutters or metal work on your house was grounded or all connected. Other then taking a meter and a super long piece of wire if there a device that can measure this through RF or other means? Say you wanted to use the gutters on your house as a lightning rod or even ground rod how would you do that if laying huge amounts of second conductor isn't doable like where the metal passes through the house. Is there a net working tool that does this?

author: AVGresponding
author_rank: Super Contributor
timestamp: February 15, 2020, 11:35:32 am
content: Generally speaking, the earth bonding should be easily visible and identifiable. That's part of the regs here in the UK, and I imagine there's similar requirements there.Sometimes there's an issue with what regs were in place when the place was built/refurbed, so if it wasn't a requirement at the time it'll not have been done.I don't think I'd want any kind of metal guttering to be used as a lightning conductor unless it was specifically designed for a dual use; I'd imagine joints in it aren't great in terms of conductivity and likely spots for arcing and fire starting...When a professional electrician tests these things, he or she uses a purpose made test device which measures the impedance of the earth connection, likethese.On occasion, it might be necessary to use something called a "wander earth lead", basically an extension lead for the earth socket on a tester, 10m or even more in length.
Is there other JTAG software to program a C8051F*** with the silicon labs JTAG  - Page 1
Forum section: electronics / beginners

author: OutThere
author_rank: Contributor
timestamp: December 30, 2022, 03:46:44 pm
content: what other software can i use besides keil/ simplicity studio to program a C8051F*** dev board with the JTAG controller , or another JTAG controller

author: MarkL
author_rank: Unknown
timestamp: December 30, 2022, 09:02:24 pm
content: I've used this package with the SiLabs EC2 stand-alone debug adapter on C8051F120 and C8051F581 processors:https://ec2drv.sourceforge.net/It supports C2 and JTAG. I don't know what debug adapter is on your dev board, but maybe there's something in ec2drv you can use.

author: OutThere
author_rank: Contributor
timestamp: January 01, 2023, 04:09:49 am
content: I have the debug adapter on the web page for the link you provided last one top right on the page. I also have a $10 clone I bought on Ebay works with Simplicity Studio 5 too. for about 2 months I thought it was from Silicon Labs till one day i looked closer and it says " SILICOM LABS"yes with an "M" Will try that tomorrow after I download.besides SDCC do you know of any other software, IDE , assemblers in C for the C8051F ?

author: MarkL
author_rank: Unknown
timestamp: January 01, 2023, 06:26:39 am
content: Quote from: OutThere on January 01, 2023, 04:09:49 amI don't. I've only ever used SDCC and EC2DRV for programming, with a custom Makefile.,
Is there place where i can have access to almost every e-book? INTERNATIONALY - Page 1
Forum section: electronics / beginners

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: November 10, 2023, 09:10:46 am
content: I am self learner, library in our village has only romantic books for grandmas... I am unable to buy everybook i want to look at. I am looking for some sort of subscription where i will pay for unlimited access to the knowledge.Do you know about something?Big thanks!

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 10, 2023, 10:24:40 am
content: Quote from: MacIntoshCZ on November 10, 2023, 09:10:46 amyou are looking at it, its called internet. you only pay your ISP fee... try to find what you are looking for (paid or free) is called google.. if you need monthly payment...https://circuitcellar.com/is one of it that i stopped subscribing long time ago due to not enough time reading. but its not every ebook on earth, its just circuitcellar. almost every ebook on earth is just i mentioned, internet...

author: MacIntoshCZ
author_rank: Regular Contributor
timestamp: November 10, 2023, 10:36:29 am
content: Ok thanks, that was really helpful. So far i have found everand.com. Also i was thinking about buying book on amazon and then return it if i come to conclusion that its not worth it, but its seems amazon did some changes in policy and i can read only 10% of book. Well thats quite a bullshit i need to look at all pages not only 10% to decide if book has some value for me...Edit: also i have found perlego.com

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: November 10, 2023, 10:42:34 am
content: Ahoi MacIntoshCZ,you might want to check "archive.org".Good luck

author: watchmaker
author_rank: Unknown
timestamp: November 10, 2023, 02:28:11 pm
content: Internet Archive

author: Mechatrommer
author_rank: Super Contributor
timestamp: November 10, 2023, 04:34:16 pm
content: here.. if you got the balls for them alone...https://www.eevblog.com/forum/beginners/electronics-primers-course-material-and-books/https://www.eevblog.com/forum/beginners/online-resources-for-self-education/

author: temperance
author_rank: Super Contributor
timestamp: November 11, 2023, 02:56:36 pm
content: I don't know if I'm allowed to posts this but for low cost books I can recommend humble bundle.

author: gogicha
author_rank: Contributor
timestamp: November 11, 2023, 03:02:17 pm
content: https://z-library.se/https://sci-hub.se/

author: mariush
author_rank: Super Contributor
timestamp: November 11, 2023, 03:17:27 pm
content: I could recommend some "less legal"/gray area websites with ebooks and alternative methods of obtaining ebooks ... not gonna post here, but if interested pm me and I'll reply with info.
Is there some way to differentiate between NAND and other flash types on a PCB? - Page 1
Forum section: electronics / beginners

author: Inume
author_rank: Newbie
timestamp: October 30, 2021, 05:24:09 pm
content: Modern devices (smartphone, notebooks) often use some kind of flash for data storage. Depending on the vendor this can be emmc, ufs, nvme and maybe even plain old NAND.The problem is you can't really find out what is used because you can't find any information on the chip and the information you can find online for the same device differs sometimes because most people don't care as long as it fast.Given some device like:https://www.ifixit.com/Teardown/Apple+TV+4K+2021+Teardown/142845orhttps://www.macrumors.com/2021/04/06/m1-mac-ram-and-ssd-upgrades-possible/is there some way you can be sure?Pinout of the chip or the pcb side? The chips on the M1 seem to have different pinouts though ...PCB layout? Voltages on some connected test points?When the chip can be replaced with some chip with more storage does this mean it is not NAND (like in the macrumors link)? iirc NAND has to be handled by the firmware so a larger size might require changes but I'm not sure about that.Is bare NAND even still used nowadays in modern smart devices?For older iphones it seemed to be NVME:http://ramtin-amin.fr/#nvmepcie
Is there something similar like Project Euler for electronics? - Page 1
Forum section: electronics / beginners

author: Ranayna
author_rank: Super Contributor
timestamp: July 19, 2018, 12:11:03 pm
content: Hi,lately, I am realising that I am missing a lot of basics, and maybe more important, also a lot of practice.Now I wonder if there is something similar tohttps://projecteuler.net/for electronics? I.E. some page that sets electronic design tasks with solutions available, with raising difficulty.I know ofwww.tronclub.comsince I saw it in one of Dave's videos, and it seems I can finaly subscribe to them without a credit-card, but is it worth it? That is not cheap, and I already have quite a stockpile of basic components, so I do not necessarily look for something that ships hardware, but on the other hand it does not have to be totally free.Are there maybe any good online courses that I could use? Preferrably those that do not bind me to a tight schedule.

author: bd139
author_rank: Super Contributor
timestamp: July 19, 2018, 12:14:02 pm
content: It's a short one but look at "A Designers Guide to Innovative Linear Circuits" (google it there's a PDF).Page 3 onwards "test your analog-design IQ".
Is there something wrong with this CR2032 holder? - Page 1
Forum section: electronics / beginners

author: ledtester
author_rank: Super Contributor
timestamp: May 02, 2025, 08:40:02 pm
content: This 2032 holder is part of a USB cable tester (first pic).When compared to a photo of one on Amazon I notice that the longer prongs are on the plus side and also they are bent at the tips.When I insert a coin cell into the cable tester holder I get continuity between the + and - terminals.There doesn't seem to be a way to remedy the problem short of replacing the holder.

author: u666sa
author_rank: Frequent Contributor
timestamp: May 02, 2025, 08:49:18 pm
content: Unbend these

author: Benta
author_rank: Super Contributor
timestamp: May 02, 2025, 08:54:43 pm
content: Quote from: u666sa on May 02, 2025, 08:49:18 pmYep. They go on the top, you need to slip the cell under them.

author: Gyro
author_rank: Super Contributor
timestamp: May 02, 2025, 09:23:39 pm
content: One of the plastic cell retaining tabs near the -ve end looks broken. You might find that the remaining one has difficulty holding the cell in, if so, be prepared to have to tape it down, 'create' a new tab with a soldering iron on the plastic, or just replace the holder. Replacing the holder isn't hard as you can unsolder and lift each contact in turn.

author: ledtester
author_rank: Super Contributor
timestamp: May 03, 2025, 02:13:27 am
content: Thanks everyone. I was able to get it to work by lifting the + prongs so they contact the side of the coin cell. I don't have the sharp bends at the tip of the + prongs like in wraper's pic or the Amazon pic I posted, but it works.
Is there such a switch device with 3-state control pin? - Page 1
Forum section: electronics / beginners

author: baoshi
author_rank: Regular Contributor
timestamp: August 10, 2015, 05:52:58 am
content: Hi,I need an switch (analog or digital) device that does this:IN CTL OUT------------X 0 0X 1 10 Hi-Z 01 Hi-Z 1May someone tell me if such device exists?ThanksBaoshi

author: Hideki
author_rank: Frequent Contributor
timestamp: August 10, 2015, 07:35:50 am
content: A single AND gate with a pull-up on the CTL input pin?

author: hamster_nz
author_rank: Super Contributor
timestamp: August 10, 2015, 07:53:34 am
content: Input a -> resistor (a few k) --> input b. ---> buffer.If B is high Z the value of A will determine the output of the buffer, otherwise it will follow input B.You might want to check the high/low levels before committing to using it...

author: Gyro
author_rank: Super Contributor
timestamp: August 10, 2015, 09:08:18 am
content: QuoteIt depends what you mean by a 'switch' - you talk about IN and OUT which sounds like a logic device, but you also say analog.If you want true switch functionality then maybe something like a 74HC4066 with appropriate pull-up / down resistors.

author: baoshi
author_rank: Regular Contributor
timestamp: August 10, 2015, 09:34:14 am
content: Quote from: hamster_nz on August 10, 2015, 07:53:34 amThanks, that is simple and elegant. The reason I'm using a comparator is I'm have a spare one in the circuit.
is this 110/220 to 5v module is safe? - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: August 23, 2017, 09:28:33 pm
content: These 110/220 to 5v step down modules are available on ebay and aliexpress. Please refer to attached image and marked area in red, I found that distance between main input and curuit is too short, just wanted to know does it matters? is it safe to have too short distance from main input.Thanks.

author: Zero999
author_rank: Super Contributor
timestamp: August 23, 2017, 10:24:34 pm
content: Quote from: sairfan1 on August 23, 2017, 09:28:33 pmIt depends on what you mean by safe?Yes, the 5V side doesn't appear to have sufficient separation from the mains and it might not be isolated at all, but that isn't a problem in some applications. If it's used as part of a device, where everything connected to that module, is treated with the same precautions as mains, then it's perfectly safe. It's only if it's used in an application, where the user isn't well enough insulated from the output of that module, that it becomes a safety hazard.
Is this 150 mili-ohm 2-3 watts resistor? - Page 1
Forum section: electronics / beginners

author: dontknwmucboutanythng
author_rank: Newbie
timestamp: May 22, 2022, 08:53:22 pm
content: Hello,Is the resistor (circled red) in the attached image a 150 mili-ohm 2-3 watts (10mm in length, 3mm diameter) resistor?Thanks.

author: Benta
author_rank: Super Contributor
timestamp: May 22, 2022, 09:17:21 pm
content: 0.15 ohm, yes, but no more than 1 W IMO.

author: Vovk_Z
author_rank: Super Contributor
timestamp: May 22, 2022, 09:56:08 pm
content: It depends. It can be 1-2-3 W rated.

author: TimFox
author_rank: Super Contributor
timestamp: May 22, 2022, 10:33:26 pm
content: For example, Dale RS-02M or C wirewound resistors have body lengths (excluding meniscus at the lead) of 12.7 mm +/- 1.6 mm and diameter 4.7 mm +/- 0.8 mm.They are rated at 3.0 W and 2.5 W, respectively (depending on ambient conditions, etc.)What are the dimensions of your part?seehttps://www.vishay.com/docs/30204/rsns.pdf

author: DavidAlfa
author_rank: Super Contributor
timestamp: May 23, 2022, 12:51:33 am
content: Probably to avoid current spikes due the inductor's parasitic capacitance?Seems 1W rating, but probably just for peak current capability, I don't think the design can safety disipate such power continuously without overheating or degrading, everything is pretty tight there.

author: dontknwmucboutanythng
author_rank: Newbie
timestamp: May 23, 2022, 02:24:37 am
content: The resistor's dimensions are 15mm x 4mm, from the table provided by Tim, it's a 3 watts part.It connected to the source of the N-MosFET. The MOSFET shorted and burned up the resistor, or was it the other way around?Anyway, the FET drove an electroluminescence display (odometer, trip meter, etc) of a car's instrument panel. The shorted FET took out a 10A automobile fuse, cut power to the instrument panel and disabled the car in the middle of the street.I am thinking of installing a fast blow inline fuse with the resistor to protect power to the instrument panel but haven't a clue of what fuse rating to use.Thanks for your thought.
Is this a 2.7G Ohm resistor?  - Page 1
Forum section: electronics / beginners

author: Edumcg
author_rank: Newbie
timestamp: November 22, 2023, 04:05:31 pm
content: Hello!I'm trying to figure out if this through hole resistor is really 2.7 G Ohm rated 1 watt. At least that's what I think by following the color code chart.The reason I doubt that is because I've tried to look on different electronics suppliers but I haven't been able to found a resistor similar to the one in the picture. I have only found metal oxide resistors which look quite different so I'm not sure if I'm in the wrong here.Any comments or guidance would be appreciated it :)PD: I did test it with a multimeter but it gave me a reading of 1.8 ohm. My multimeter only goes up to mega ohm.

author: Dan123456
author_rank: Regular Contributor
timestamp: November 22, 2023, 04:15:09 pm
content: The grey might actually be silver giving you a 0.27 ohm resistor rather than 2.7G ohmWhy you are getting a reading of 1.8, I’m not sureDoes your meter read 0.00 if you touch the leads?

author: Edumcg
author_rank: Newbie
timestamp: November 22, 2023, 04:53:03 pm
content: Lol you are totally right. I don't why my head was stuck thinking it was grey and not silver. The table I was looking at didn't have silver so that didn't help. Thank you very much!Regarding your question on the 0.0 reading, well it depends. When I touch the leads sometimes reads 1.8 ohm others 0.7 so maybe my equipment is faulty .... I will replace the battery or maybe get a different one from a friendAlthough with a 180 resistor it reads 177 ohm which is not that far off, still I will do the mentioned above

author: ebastler
author_rank: Super Contributor
timestamp: November 22, 2023, 06:01:54 pm
content: Quote from: Edumcg on November 22, 2023, 04:53:03 pmClean the probe tips with contact cleaner (organic solvent and deoxidant), especially if they are not gold-plated. And push them together with a bit of pressure when you touch them. Likewise, apply a bit of pressure when connecting the leads to the resistor, to give good contact and penetrate potential oxide layers. That should give you a more stable reading.

author: Vovk_Z
author_rank: Super Contributor
timestamp: November 22, 2023, 06:45:18 pm
content: Quote from: Edumcg on November 22, 2023, 04:05:31 pmAnd typical resistors usually are manufactured up to several megaohm (up to 10-20 MOhm). Higher values are used very rarely and usually need special resistor design. Your resistor looks quite usual so it can't be of a gigaohm range.
Is this a breadboard problem - Page 1
Forum section: electronics / beginners

author: chancs
author_rank: Contributor
timestamp: October 04, 2019, 07:23:54 am
content: I built an opamp circuit on a 3M breadboard. There is a 560pF cap in place to keep the opamp from oscillating, no problem at all. However, sometime when I remove this cap, the opamp will remain stable. Another time I remove it, the circuit will oscillate. Something if I tile the jumper wire at an angle, the circuit will oscillate. So, is this problem caused by the breadboard or the circuit itself is at the edge of stability?

author: Ian.M
author_rank: Super Contributor
timestamp: October 04, 2019, 08:56:06 am
content: As my crystal ball is clouded today, and I'm not aware of any publicly accessible three letter agency surveillance feeds from your lab, we'll need a photo of the assembled breadboard and a schematic please.

author: magic
author_rank: Super Contributor
timestamp: October 04, 2019, 04:44:02 pm
content: My crystal ball says that a jungle of tangled cables doesn't do well to electronics and moving such cables around can easily increase or reduce crosstalk and therefore affect behavior of the circuit. So that's nothing suspicious by itself.As for some hypothetical alternative PCB realization of your undisclosed circuit, hell, that's gonna take tea leaves
Is this a capacitor? - Page 1
Forum section: electronics / beginners

author: ollihd
author_rank: Regular Contributor
timestamp: March 29, 2017, 09:32:48 pm
content: If so, what does the "1HE" stand for?

author: ollihd
author_rank: Regular Contributor
timestamp: March 29, 2017, 09:33:58 pm
content: Cap sign is on the board...no idea about the 1HE though.

author: cvanc
author_rank: Frequent Contributor
timestamp: March 29, 2017, 09:54:20 pm
content: Yes it is a capacitor; a film cap of some type (polyester probably as they are most common, but maybe polypropylene or polystyrene).The '104' is the value - 1, then 0, followed by 4 more zeros. So it's a 100,000pF or 0.1uF cap (2 ways of expressing the same value).Hope this helps.

author: edpalmer42
author_rank: Super Contributor
timestamp: March 29, 2017, 09:57:37 pm
content: The 1HE is probably a date code or lot number.The only important part is the 104K which is the value (104 = 10e4 pf) and 'something else'. The 'something else' could be a code for the type of dielectric or maybe tolerance. Capacitor labelling can be a huge pain to figure out. I just found this pagehttp://www.wikihow.com/Read-a-Capacitorwhich seems to be reasonably complete. YMMV.Ed

author: TimFox
author_rank: Super Contributor
timestamp: March 29, 2017, 11:01:13 pm
content: Probably, the "K" means 10% tolerance.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 29, 2017, 11:01:28 pm
content: 1H is the voltage rating code for 50V.http://www.radio-electronics.com/info/data/capacitor/capacitor-markings.phpTim

author: ollihd
author_rank: Regular Contributor
timestamp: March 30, 2017, 09:53:45 am
content: Thanks a lot everyone!
Is this a ceramic cap or a varistor? - Page 1
Forum section: electronics / beginners

author: fabiodl
author_rank: Frequent Contributor
timestamp: August 21, 2022, 10:45:40 am
content: Is this a ceramic cap or a varistor? I have only the pic so I cannot measure.

author: inse
author_rank: Super Contributor
timestamp: August 21, 2022, 11:24:30 am
content: I guess it's a 390pF ceramic cap.

author: Ian.M
author_rank: Super Contributor
timestamp: August 21, 2022, 11:30:36 am
content: Trace separations and widths look inadequate for mains power, so the odds of it being a varistor are pretty low before you even consider the markings.

author: fabiodl
author_rank: Frequent Contributor
timestamp: August 21, 2022, 01:26:29 pm
content: Yep, it's on a 5V rail so I was 90% confident it's a cap, but even that it makes little sense.It's on the output of a LS04 on a totally logic circuit. I guess they wanted to slow down the edge.

author: Kleinstein
author_rank: Super Contributor
timestamp: August 21, 2022, 01:41:34 pm
content: 390 pF make a lot more sense than a 390 V varistor. Sometimes LS logic was also used for some more analog functions. Some delay of noise filtering is possible, but also just an oscillator.

author: Ian.M
author_rank: Super Contributor
timestamp: August 21, 2022, 01:45:17 pm
content: Quote from: fabiodl on August 21, 2022, 01:26:29 pmIt looks like that sort of bodgery. I'd bet there's a nasty asynch race condition somewhere upstream of it. Typical 'design' process is late one Friday evening, with the deadline vanishing in the rear-view mirror:Tech: "Eureka! It actually works now if I probe it here with a x1 scope probe!"Engineer: "Oh S--t!, we've got a glitch. Its probably a race condition, but I'll need a couple of days to track it down and fix it. May need a board re-spin."Boss: "Hell NO! The customer is already screaming, so its got to be done tonight. Redesign denied."Engineer: Try bodging in a 39pF cap. If it fixes it, we'll go up an order of magnitude so it *STAYS* fixed."

author: Gyro
author_rank: Super Contributor
timestamp: August 21, 2022, 04:32:11 pm
content: That's been used as an alternative to shipping with a scope probe attached many times!
Is this a Carbon or Metal Film resistor?  - Page 1
Forum section: electronics / beginners

author: gjpmho
author_rank: Contributor
timestamp: May 24, 2022, 03:48:55 am
content: Hi All,I'm repairing an amp and noticed some of the resistors that were installed in manufacturing don't appear to match the service manual. In this particular case, these resistors are noted as "critical" in the service manual. the part number is CFPS1/4https://www.koaspeer.com/pdfs/CF.pdfFrom the datasheet you can tell the service manual lists a Carbon Film Flame Proof resistor with a 1/4Watts power rating.What I'm seeing on the board is green/blue resistor which typically are Metal Film resistors, while orange/brown are typically Carbon Film resistors. I've removed one the resistors (which was burnt). Can anyone tell from these photos if this is indeed a Metal Film or Carbon Film resistor?Thanks for the help.

author: Gyro
author_rank: Super Contributor
timestamp: May 24, 2022, 04:39:43 pm
content: Welcome to the forum.Yes, the photos do look rather like metal film resistors - but flameproof resistors always look different due to their cement coating rather than the normal lacquer. One way to solve the question would be to remove another resistor of the same type and check its temperature coefficient. With a metal film resistor you would normally expect around 50ppm/'C, a carbon film rather higher (according to the datasheet too), typically by about an order of magnitude.As a rule of thumb, normally you can measure the resistance of a metal film resistor held in your fingers and measure a pretty stable resistance value (avoiding any leakage effects). With a carbon film resistor, you will see the value slowly drift with the heat of your fingers. If you have one of each type to hand, you can compare too. I can't get an idea of scale from your photos, but a carbon film resistor will typically be larger for the same power rating too, check the dimensions against the datasheet.As you indicate these resistors are in 'critical' positions, intended to fail safely and prevent other parts of the circuit from catching fire, so you should probably replace with the same flavour of flameproof.

author: strawberry
author_rank: Super Contributor
timestamp: May 24, 2022, 04:48:59 pm
content: carbon film resistors usually are not better than 5%

author: magic
author_rank: Super Contributor
timestamp: May 25, 2022, 12:58:27 pm
content: I would say the dark resistive layer looks like carbon, MF resistors are grey inside.Photograph on the first page of your CF resistor datasheet shows a few green ones.I have seen green resistors in places where there would be no reason to use MF.

author: gjpmho
author_rank: Contributor
timestamp: June 22, 2022, 10:48:33 pm
content: Carbon Film resistor, confirmed by KOA Speer.https://www.koaspeer.com/pdfs/Appendix_D.pdf

author: gjpmho
author_rank: Contributor
timestamp: June 22, 2022, 10:50:09 pm
content: Thanks for the help.
is this a effectively a low and high side switch? or a double high side? - Page 1
Forum section: electronics / beginners

author: superwester
author_rank: Contributor
timestamp: February 17, 2018, 08:46:51 pm
content: i was struggling thinking that i needed to control two high side switches.but on a second though, as the circuit is powered by a bipolar supply its a good old high and low side half H bridge.am i right?sorry if this requires more info from my part, but im assuming it does not.

author: neko efecktz
author_rank: Regular Contributor
timestamp: February 18, 2018, 08:48:30 pm
content: Before anyone can give you a answer, please explain your descriptionhigh sideandlow sidePlease include a couple of pictures of the switch in question.Is it an electronic switch or a physical mechanical switch?BILL.

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 18, 2018, 09:08:53 pm
content: double post herehttps://www.eevblog.com/forum/beginners/is-this-a-typical-high-and-low-side-switching-circuit/msg1430243/#msg1430243Quote from: superwester on February 18, 2018, 04:13:06 amthere is "Modify" button on top right of each post you can edit your post to include whatever you want to link... fwiw...
Is this a fuse and what is this yellow triangle with an exclamation point about? - Page 1
Forum section: electronics / beginners

author: Sirgeorge
author_rank: Contributor
timestamp: September 24, 2020, 05:37:30 am
content: Just a quick confirmation, this is a fuse symbol, correct? Also, what is the meaning of the yellow triangle with the exclamation mark in it?

author: Sirgeorge
author_rank: Contributor
timestamp: September 24, 2020, 05:39:19 am
content: I'm an idiot.

author: ebclr
author_rank: Super Contributor
timestamp: September 24, 2020, 05:41:51 am
content: Agreed
Is this a good budged begginer multimeter safety wise? (Ignore the bodge) - Page 1
Forum section: electronics / beginners

author: FileNotFound__
author_rank: Contributor
timestamp: January 09, 2022, 07:32:25 pm
content: Here is a multimeter I've been given few years back when I started with arduino.So recently I've been getting into repairs lately and I heard a lot about safety concerns about equipment.What I want to know is is this multimeter safe for high voltage use, repairs and stuff.The fuse bodge is my masterpiece from when I menaged to short the current range over a car battery.The fuse I added on current range, I've seen EEV Blog's video on fuses and decided to put an 8A fuse in a 10A current meter,was that a smart thing to do?The reason I didn't mention the multimeter model number or brand is because I want to know about this specific multimeter, not really about the brand.I will later show the brand.

author: Ian.M
author_rank: Super Contributor
timestamp: January 09, 2022, 07:45:33 pm
content: Glass fuses do not inspire confidence. If the lower one is original, I certainly wouldn't want to use the meter for anything over Cat I 300V, and I doubt it even meets that standard. With your modification its certainly unsafe for use on any circuit that doesn't fall in theSELVcategory. Your bodge was a bad idea - you should have bought a set of fused test leads.

author: Hannibal_Hector
author_rank: Newbie
timestamp: January 09, 2022, 07:52:05 pm
content: Could not resist Googling...Uni-T UT108/UT109, board manufactured by Jiaxin

author: Ian.M
author_rank: Super Contributor
timestamp: January 09, 2022, 08:02:39 pm
content: Ah, thats interesting. The UT108/UT109 current ranges are labelled 250V max, which is consistent with glass fuses. That also makes the claimed CAT IV 600V, CAT II 1000V rating for the Volts/Ohms & other functions jack moot as one moment of inattention with the leads could result in shorting a high energy supply via one of the non-CAT rated current ranges and an exploding meter.

author: Hannibal_Hector
author_rank: Newbie
timestamp: January 09, 2022, 08:11:47 pm
content: Hmm... I could be very wrong on the UT108/UT109. The hit I got was on the E210448 and the KS symbol, and that might only be a generic ID for the JIAXIN PRINTED CIRCUIT BOARD MFR.My new guess is a Uni-T 30 Series, like the UT39A, which matches the jack positions, transistor test point, capacitance test, power and hold buttons:https://www.uni-t.cz/en/p/multimeter-uni-t-ut-39a

author: FileNotFound__
author_rank: Contributor
timestamp: January 09, 2022, 09:15:20 pm
content: It is indeed an UNI-T UT39a

author: FileNotFound__
author_rank: Contributor
timestamp: January 09, 2022, 09:45:16 pm
content: I didn't know fused test leads were a thing.
Is this a polyfuse? - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: March 19, 2019, 05:33:19 am
content: I bought an Arduino Mega from eBay. After I bought it, I noticed that it was a bit different to the actual Arduino Mega, in that the USB to Serial converter was different and that there didn't appear to be a polyfuse there. I got it, and had a look, and there appears to be some component there, but it doesn't look like the normal polyfuse on Arduino. Is this component a polyfuse, and will it protect my laptop and the Arduino board if I accidentally short circuit something?

author: skillz21
author_rank: Frequent Contributor
timestamp: March 19, 2019, 06:19:02 am
content: Quote from: blueskull on March 19, 2019, 05:41:49 amAny way to find out which? Without actually shorting it?

author: skillz21
author_rank: Frequent Contributor
timestamp: March 19, 2019, 06:25:39 am
content: Alright. Like the idiot that I am, I tested it by shorting 5v to ground. It still works fine, but I think if I leave the short connected for a while, the polyfuse will burn out, because, as expected, it gets really hot, really fast when shorted. I'm assuming dissapiation is primarily why they make them a larger size?

author: skillz21
author_rank: Frequent Contributor
timestamp: March 19, 2019, 07:52:02 am
content: Oh... Wait so I can short it indefinitely, and it will be fine?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: March 19, 2019, 07:53:22 am
content: The less damaging way* is to heat it, to about 150C, at which point the resistance should increase dramatically.*Unless it turns out to be a thermal fuse, in which case you're screwed again.Offhand, it plausibly looks like a Bourns polyfuse (or whatever name they use), I think. Would guess the 4 is either the amperage, or a type code.Tim