hybridfree/eevblog-posts huggingface dataset:
Non-rechargeable Battery Gauge circuit / Coulomb counter - Page 1
Forum section: electronics / beginners

author: Sultanpepper123
author_rank: Regular Contributor
timestamp: July 01, 2020, 12:12:16 pm
content: I'm trying to find a cheap implementation/circuit to monitor the remaining capacity of a non-rechargeable battery to be specific Lithium thionyl chloride LiSOCI2 batteries. I am aware of TI and Maxim's solutions but i feel they are expensive, i found several coulomb counter projects but AFAIK they fully discharge the batteries to finish the test which for LI-ion (rechargeable) this is not a problem. I was thinking if it was possible to do with simple components (Transistors/Mosfets) and software using a microcontroller to do ? I would really appreciate if someone would point to the right direction. For the curious out there, it's going to be inlcuded in an energy/electricity meter. Thanks in advance.

author: David Hess
author_rank: Super Contributor
timestamp: July 02, 2020, 02:08:50 am
content: If this is for a micropower application, then I would implement an inductive charge pump regulator which uses a discontinuous switching regulator. Then counting each cycle of the switching regulator reveals how much energy has been transferred.If you just want to detect end of life, then maybe measuring the internal resistance of the battery would be sufficient. The internal resistance rises as the battery discharges.
Non-standard Potentiometer with on/off  - Page 1
Forum section: electronics / beginners

author: Rjc987
author_rank: Contributor
timestamp: June 17, 2021, 05:17:05 pm
content: Hi all - I’m trying to replace a pot with a broken stem in a piece of equipment but it’s unusual. It’s 500k, about 300 degree with a hard snap-action “on” detent at the beginning of travel, which is all pretty normal so far BUT… every pot I’ve found so far has the normal 3 terminals for resistance PLUS 2 extra terminals on the back for the on/off functionality. This one only has the 3 normal leads which are arranged as expected and that go open circuit when the pot is switched off. I cant for the life of me find the right search terms to find a replacement. The markings on it are custom (pc1313x1) and only point you to the manual and suppliers of the whole board assembly (see attached) who mention that the part is obsolete and out of stock (very helpful…). Any ideas?

author: drvtech
author_rank: Regular Contributor
timestamp: June 17, 2021, 05:46:34 pm
content: Can't you just use a standard switched pot (with the extra switch terminals) and connect the switch in series with the wiper?

author: bob91343
author_rank: Super Contributor
timestamp: June 17, 2021, 06:14:14 pm
content: You need to disconnect all three terminals when the switch is open? Maybe you can alter the circuit to use a single pole switch. I think, also, that there were some double pole switches that were on the back of pots in the old days. If you can find one of those you are home free. Else you can add a relay to do the job.

author: Rjc987
author_rank: Contributor
timestamp: June 17, 2021, 10:16:51 pm
content: Ugh, thank you @drvtech - I feel like a total moron. I was measuring everything in circuit and assumed the two big soldered lugs with continuity were just case grounded tabs for mounting. I didn’t even consider they were doing that all along, or think to check it in the “off” position. 🤦🏻‍♂️
Non-standard resistor value? - Page 1
Forum section: electronics / beginners

author: overlordManny
author_rank: Newbie
timestamp: February 14, 2019, 03:53:00 am
content: Hi everyone. I'm a bit of a noob. Even though I've been formally trained in electronics by the USAF it's been many, many years since I've done much electronics repair work.I have an old Nintendo 64 power supply that's giving me no output at all. I'm not terribly familiar with switch mode power supplies, but from what I can understand it looks like I may have an open somewhere on the primary side( no fuses blown). I found a resistor that seems to be reading high at 68.2M ohms. When I look up the color code, (blue, grey, green, gold, green), it looks like it should be 68.5 ohms at .5% tolerance, which is apparently non-standard. Looking at the numerical values, they seem too close to be a coincidence. What am I missing/not understanding. Here's a picture...

author: tooki
author_rank: Super Contributor
timestamp: February 14, 2019, 04:09:56 am
content: Could it be a fusible resistor that uses a nonstandard color code, at least for some of the bands? (I think there was a discussion of those on here a few months ago.)

author: golden_labels
author_rank: Super Contributor
timestamp: February 14, 2019, 04:14:12 am
content: digit1 | digit2 | multiplier | tolerance | temperature coefficient?That would be: 6.8MΩ, 5%, 20mmp/K.

author: overlordManny
author_rank: Newbie
timestamp: February 14, 2019, 04:27:53 am
content: Quote from: golden_labels on February 14, 2019, 04:14:12 amThat correct! I just found this on allaboutcircuits, amazing how you find answers after you post questions."Color Code Exceptions5 Band Resistor with a 4th Band of Gold or SilverFive band resistors with a fourth band of silver or gold form an exception, and are utilized on specific or older resistors. The first two bands represent the significant digits, the third band is a multiplication factor, the fourth band is for tolerance and the fifth band is for the temperature coefficient (ppm/K)."Guess that's not my power supply problem. haha The search continues.
Non-zero voltage on tranformer secondary with circuit to primary being open - Page 1
Forum section: electronics / beginners

author: giosif
author_rank: Frequent Contributor
timestamp: March 04, 2015, 07:58:11 pm
content: Hi,Sorry for the newbie/basic/naive question, but could someone please tell me how it is possible to see approx 16 Vac on a transformer secondary (relative to the Earth ground), all this while the circuit from the mains to the primary is open (both Live and Neutral lines are controlled by a DPST switch)?[Later edit] I should add that the mentioned voltage is present only when the (open) circuit to the primary is connected to the mains.Thank you!Best regards,George

author: JohnnyBerg
author_rank: Frequent Contributor
timestamp: March 04, 2015, 08:08:36 pm
content: Hi George,Stray capacitance between primary and secondary?Put a 1K resistor in parallel with your meter, and test again.

author: giosif
author_rank: Frequent Contributor
timestamp: March 04, 2015, 11:58:10 pm
content: Quote from: JohnnyBerg on March 04, 2015, 08:08:36 pmHi,You are right: no voltage with a 1K resistor in parallel with the meter.Any pointers where I could read more about this behaviour?Thanks!Regards,George
None of the personal messages are appearing - Page 1
Forum section: electronics / beginners

author: ricko_uk
author_rank: Super Contributor
timestamp: November 15, 2020, 04:49:12 pm
content: Hi,how do I see sent messages?I sent already at least 3 messages in the past few months to a couple of users and they do not appear in my sent message window. See attached screenshot.I received two answers and only one still appears in my inbox.I definitely did no delete any, that is 150% sure.I just sent another one and it shows clearly the green box "successfully sent" then when I went to the sent folder/area absolutely none of the messages appear...How do I see all my messages both sent and received?Thank you

author: ataradov
author_rank: Super Contributor
timestamp: November 15, 2020, 07:50:23 pm
content: In the profile settings there is a checkbox "Save a copy of each personal message in my sent items by default.". It needs to be checked, otherwise sent messages would be discarded.

author: ricko_uk
author_rank: Super Contributor
timestamp: November 15, 2020, 08:44:05 pm
content: Thank you ataradov!What's the logic of that??Great forum to say the least!! But such absurd setting that needs to be set (i.e. off by default)?? That's insanely bizarre...

author: wraper
author_rank: Unknown
timestamp: November 15, 2020, 08:46:14 pm
content: Quote from: ricko_uk on November 15, 2020, 08:44:05 pmMaybe it's weird. But there is also a checkbox to save the message when you are sending it.

author: ricko_uk
author_rank: Super Contributor
timestamp: November 15, 2020, 08:50:10 pm
content: Thank you Wraper,but regardless, do you check a tick box every time you send an email or a message on any of the social media?Why would anybody not want to keep the messages...?I don't understand the logic of that, whoever implemented it...

author: wraper
author_rank: Unknown
timestamp: November 15, 2020, 08:59:37 pm
content: Quote from: ricko_uk on November 15, 2020, 08:50:10 pmSo wife cannot read them... You dumbass, yet again you bought some boat anchor!
nonlinear inductance vs current - Page 1
Forum section: electronics / beginners

author: fonograph
author_rank: Frequent Contributor
timestamp: October 15, 2017, 03:28:58 pm
content: I was reading article about distortion sources in class D amplifiers for audio and there was one thing mentioned that surprised me.There was written that inductance of simple coil inductor varies with current.Now,I know that alot current will heat the copper wire and higher the temperature,higher the resistance but I am not entirely sure that was the thing that the article meant.Did that article meant just normal heating and resistance rise,or is there some intrinsic nonlinear inductance change vs current that inductors have? I have never heard or read anything suggesting that there is such thing,so I want to ask you experts to tell me how it is.

author: PChi
author_rank: Frequent Contributor
timestamp: October 15, 2017, 03:46:08 pm
content: If the inductor has a ferrite core the permeabilityhttps://en.tdk.eu/download/528882/3226013b0ed82a6a2af3666f537cbf83/pdf-n87.pdf(which determines the inductance along with the core dimensions) varies with flux density which varies with current.

author: Benta
author_rank: Super Contributor
timestamp: October 15, 2017, 06:39:37 pm
content: QuoteThis is only true for inductors with core. Air inductors have no current linearity issues (but a lot more interwinding capacitance).

author: Zero999
author_rank: Super Contributor
timestamp: October 15, 2017, 10:33:51 pm
content: A similar thing can happen with some cheaper, high capacitance ceramic capacitors: the capacitance falls at higher voltages.http://www.murata.com/en-us/support/faqs/products/capacitor/mlcc/char/0005Another mechanism for distortion is magnetic hysteresis in inductors and dielectric absorption in capacitors.
NOOB boot question STM32 - Page 1
Forum section: electronics / beginners

author: anda3243
author_rank: Contributor
timestamp: May 03, 2022, 08:49:35 am
content: HelloI have connected and been able to program my MCU and board.Adventures in setting this up can be found herehttps://www.eevblog.com/forum/microcontrollers/stm32f103t8u6-not-recognized-by-cubeide-as-genuine/Now I am using Crosworks IDE from Rowley and I am able to create the basic functions I need.So far the board is powered from the ST-Link V2 programmer. And the SW can be initiated via the IDE and it works as expected.Now I want to power my board from a battery, and have it boot up when VCC is applied. But I can not get it to work. I can only initiate it via the programmer and IDE, but not on its own.I am sure that there is some simple setting, but I have spent hours on google without anything useful.I only need a simple function. When power is applied, it should boot up.I have a breadboard prototype, and it powers up when voltage is applied, as expected. But not the custom board with the smaller mcu.I have tried pulling BOOT0 high and BOOT0 low during programming, without any luck.I am new to programming, and I have been able to get along quite good with youtube tutorials and articles, but this seems to be a topic that is not covered very well. Or I am not searching for the right keywords.Thank you very much in advance!

author: AndyC_772
author_rank: Super Contributor
timestamp: May 03, 2022, 11:16:32 am
content: Set the preprocessor definition STARTUP_FROM_RESET.You'll find out where it's used and why if you open up the system file STM32_Startup.s

author: anda3243
author_rank: Contributor
timestamp: May 03, 2022, 11:54:03 am
content: Thank you AndyI will do some reading and testing and report back.

author: anda3243
author_rank: Contributor
timestamp: May 03, 2022, 12:28:02 pm
content: SOLVEDQuote from: AndyC_772 on May 03, 2022, 11:16:32 amThank you, it worked. I even found some more info about it.https://electronics.stackexchange.com/questions/359381/rowley-crossworks-stm32-start-from-reset
noob circuit question.  hardware for software dummies help! - Page 1
Forum section: electronics / beginners

author: wblackledg
author_rank: Regular Contributor
timestamp: February 18, 2015, 08:09:08 pm
content: I'm a software guy, not a hardware guy so I think in terms of setting up a program.I have this book (see link). Amazon allows you to view even / odd pages so lucky for me my question resides on On page 86.http://www.amazon.com/Make-Electronics-Discovery-Charles-Platt/dp/0596153740/ref=sr_1_1?ie=UTF8&qid=1424186364&sr=8-1&keywords=make+electronics#reader_0596153740Question:Looking at the circuit on page 86, they place the resistor (R6) behind the transistor in the flow. As a programmer I would think it would be in front of the transistor because you are trying to limit the current. However is this resistor like a stopper on a sink, in that the juice is flowing out of the faucet, and by putting the resistor behind the transistor you are cutting the flow off as it drains out? Hope that makes sense. Just wondering if I understand why the resistor is placed where it is.hope that makes sense?thanks in advance.

author: Christopher
author_rank: Frequent Contributor
timestamp: February 18, 2015, 08:25:18 pm
content: The base-emitter junction is like a diode. You have to limit the voltage across it otherwise it will just allow too much current through it, damaging the device.The same reason why you put a dropper resistor in series with an LED

author: wblackledg
author_rank: Regular Contributor
timestamp: February 18, 2015, 08:35:13 pm
content: Quote from: Christopher on February 18, 2015, 08:25:18 pmok thanks for responding. However I'm still not sure why the Resistor goes behind transistor and not in front of it?

author: wblackledg
author_rank: Regular Contributor
timestamp: February 19, 2015, 03:51:29 am
content: I think I figured it out after looking at it again.thanks.

author: Seekonk
author_rank: Super Contributor
timestamp: February 19, 2015, 04:08:47 am
content: "behind transistor and not in front of it? "For the life of me I can't figure out what that means.

author: wblackledg
author_rank: Regular Contributor
timestamp: February 19, 2015, 04:13:13 am
content: Quote from: Seekonk on February 19, 2015, 04:08:47 amI meant that flow of electricity. The resistor connection was after the transistor in the circuit. It didn't make sense, but believe it does now.thanks.
noob compatible 5A constant current supply - Page 1
Forum section: electronics / beginners

author: helobin
author_rank: Newbie
timestamp: January 28, 2016, 12:47:11 pm
content: Hello everyone,I've been struggling trying to get a constant current supply working for a specialised heating element- it's quite sensitive and works best if it can be set to specific current and held there to within around 10ma. The element is about 0.5 ohm cold and 1-2 ohms depending on operating temperature - ideally it would be able to be operated from 4A to 5.5 A continuous.I tried a buck converter from eBay, but the current regulation seemed very primitive. It made a buzzing noise and when I got an opportunity to look at the output with a scope it looked like it was using some kind of really slow pwm to limit the current (300 hz or so). With the current limiting off the output looked OK, ripple around the 150khz switching frequency but that's OK for this application.Is the primitive current regulation how these cheapo buck modules do it?The whole project will be running of a micro when its done, so I was thinking I could sense the current and then control the voltage of the buck converter but it seems silly to be feedback looping around a device that must itself contain some kind of loop...The options I can think of are:- stick with the cheap buck module and add an external current sensing set up- source a better buck module (seems like the super cheap ones are all that's out there in these modules!)- try and build my own buck module -- this would be an interesting project but I've got a history of jumping into making what sounds like a simple thing to make and then getting caught up in the inevitable complexities of perfecting it and then it taking months to get working!- try and get some kind of linear supply.... not sure where I would start with thatI couldn't find much info on adjustable current sources except for much lower output led ones. Does anyone know of something I could modify or adapt for my heater? What do people think of these cheap buck converters as far as reliability etc goes?

author: uncle_bob
author_rank: Unknown
timestamp: January 30, 2016, 06:09:40 pm
content: HiOk, so your output will be 5A times half ohm = 2.5V at cold and as much as 10V when the element is hot. The regulator will be putting out 12.5W at the cold end and as much as 50W at the hot end.Most of the constant current stuff you see on eBay is designed for things like LED lighting. They are not a good match to your needs. If 50 W is indeed correct for the max load, a 90% efficient supply will be dumping 5W. That's doing quite well at max load and it's going to require some level of heat sinking.Do I have this right so far?Bob
:: noob HF PCB question - Page 1
Forum section: electronics / beginners

author: 3roomlab
author_rank: Frequent Contributor
timestamp: October 15, 2015, 09:33:43 am
content: i need some help in understanding the terminology/unit here, while searching the web to learn new stuff about high frequency PCB traces, i ran into this web calculator.http://www.emtalk.com/mscalc.php?er=4.2&h=1.6&h_units_list=hmm&f=20&Zo=50&EL=360&Operation=Synthesize&Wa=&W_units_list=Wmm&La=&L_units_list=Lmmwhat does it mean when it says electrical length in "deg" ?

author: dmills
author_rank: Super Contributor
timestamp: October 15, 2015, 09:48:05 am
content: The number of wavelengths the line is long at the operating frequency expressed as degrees of phase rotation.Important because (for example) a 90 degree open circuit stub will appear as a short circuit at its driven end due to the reflection from the open end returning delayed by 180 degrees (90 out + 90 back).Many microwave circuit elements are made as printed patterns of the PCB substrate, filters, matching (and phase shift) networks, all that stuff is just printed patterns, often of carefully calculated transmission lines or stubs.

author: 3roomlab
author_rank: Frequent Contributor
timestamp: October 15, 2015, 10:48:43 am
content: Quote from: dmills on October 15, 2015, 09:48:05 amthanks
Noob looking to buy a power supply to get away from using 9-volt batteries - Page 1
Forum section: electronics / beginners

author: chewmanfoo
author_rank: Newbie
timestamp: July 20, 2017, 02:23:20 am
content: I may be keeping Duracell in business for the past few months, but it's time for me to stop using 9-volts and move on to a power supply.I don't know much about what to look for in a power supply - but I won't ask such a general question. Just a specific one.Why does the HP 6612C not have a ground post on the front? Most power supplies have 3 posts - two red and one back. But this one doesn't have the black. Why?TIA!

author: SkyMaster
author_rank: Frequent Contributor
timestamp: July 20, 2017, 03:00:06 am
content: Quote from: chewmanfoo on July 20, 2017, 02:23:20 amIn the User's Guide, there is a note that reads:"NOTE: Front panel binding posts are provided for convenience. Only the rear panel terminals are optimized for noise, regulation, and transient response as documented in Appendix A."There is a 5-pin connector in the back where the ground is accessible.

author: chewmanfoo
author_rank: Newbie
timestamp: July 20, 2017, 03:03:58 am
content: wow - excellent - thanks! I assume you own one? Is it reliable? Any timebomb capacitors I should be worried about?

author: SkyMaster
author_rank: Frequent Contributor
timestamp: July 20, 2017, 03:31:23 am
content: Quote from: chewmanfoo on July 20, 2017, 03:03:58 amNo, I do not have this one, and have never used one either. But I have a HP E3617A, which is totally different.I would not worry about problematic capacitors in a HP 6612C, as this is a fairly recent power supply, and HP uses high quality components.

author: alm
author_rank: Super Contributor
timestamp: July 20, 2017, 06:04:46 am
content: My speculation:1. They recycled the front panel design from other instruments (e.g. function generators). If they wanted space for three binding posts, they would have had to redesign the front panel.2. Because these are precision power supplies, substantially more expensive than standard bench supplies like the E3617A, I suspect a large fraction of users would use the connector on the back so they can use remote sensing. Compared to a more basic power supply that is more likely to be used without remote sensing.

author: ngjohnson
author_rank: Contributor
timestamp: July 20, 2017, 06:23:49 am
content: As you keep working on electronics having a power supply that has current limiting and over voltage is a must! Check out this cheap power supply. I have used it for a large range of projects and for the price it's a solid PSU.Buy onAMAZONPS: Does anyone know how to make the hyperlink work?https://www.amazon.com/KORAD-KA3005P-Programmable-Precision-Adjustable/dp/B0085QLNFM/ref=sr_1_2?ie=UTF8&qid=1500531464&sr=8-2-spons&keywords=dc+lab+power+supply&psc=1
Noob need help - Page 1
Forum section: electronics / beginners

author: nasrul22
author_rank: Newbie
timestamp: June 05, 2013, 09:25:52 am
content: Hi sifus...I need to design a simple jig that when a button is pressed 3 times, a LED will switch ON. The jig has 2 buttons, so each button needs to be pressed 3 times and there will be an LED for each button. I am completely new in this field, therefore I need your advice on what I can use and apply (eg. microcontroller,etc.). I want to make the jig as simple and small as possible, so I'm ruling out PLCs and other similar methods that require more space.

author: Rerouter
author_rank: Super Contributor
timestamp: June 05, 2013, 09:33:03 am
content: something like an ATtiny micro would probably suit, otherwise use 2 shift registers, tie the serial in high and connect the debounced buttons to the clock pins and on the 3rd output connect your led, so you clock it 3 times, and bam led on,for reseting it, almost every shift register out there has a clear / reset pin,

author: david77
author_rank: Frequent Contributor
timestamp: June 05, 2013, 09:42:58 am
content: Use a CD4017 decade counter. Debounced button on the input, LED on output Q2. The counter has a reset input, connect that to Q3 and the counter resets with another push of the button. Easy.

author: hlavac
author_rank: Frequent Contributor
timestamp: June 05, 2013, 09:45:58 am
content: Do you have power supply available?Is your output just LEDs?Buttons switch to ground or something else?Do you have means to program ATtiny or Pic?How about turning the LEDs off?The small form factor and ease of doing a mildly complicated button stuff lend themselves to a small microcontroller.
Noob oscilloscope question - Page 1
Forum section: electronics / beginners

author: GoldSrc
author_rank: Contributor
timestamp: January 25, 2015, 12:35:31 am
content: Hi, I'm new to the forum but I've been a long time EEVblog youtube viewer.I'm thinking about buying an analog oscilloscope and I have a few questions.Is 20MHz good enough?, I will mostly use it to do some testing on some old VCRs that I have, and to learn how to use it since I always wanted to have one since I was 12,and maybe my friends may use it for their cars.I can get a 20MHz Kenwood CS-4025 for around 80-85 US dollars, the guy who sells it doesn't have the probes but I can buy those.80-85 US dollars may not be ebay-cheap but I think is cheap, buying one from ebay would cost me more with the shipping to my country.I was going to get a 40MHz one but the guy sold it xD.Are Kenwood scopes good?

author: Leadfootin
author_rank: Contributor
timestamp: January 25, 2015, 01:16:20 am
content: If you can afford it just buy the Rigol 1045Z. Far more versatile and will show you a lot that is very hard to see on the analog scope.

author: tautech
author_rank: Super Contributor
timestamp: January 25, 2015, 01:26:56 am
content: Kenwood are a known brand and I could not say bad of them.But with all older equipment make sure you can get a Service manual for it.Without a manual don't touch it.

author: GoldSrc
author_rank: Contributor
timestamp: January 25, 2015, 02:41:26 am
content: Quote from: Leadfootin on January 25, 2015, 01:16:20 amI'm too broke to buy that right now.

author: GoldSrc
author_rank: Contributor
timestamp: January 25, 2015, 02:44:32 am
content: Quote from: tautech on January 25, 2015, 01:26:56 amOh I found the service manual in this threadhttps://www.eevblog.com/forum/testgear/odd-%28almost%29-vintage-iranian-oscilloscope/so that shouldn't be a problem.

author: rsjsouza
author_rank: Super Contributor
timestamp: January 25, 2015, 03:08:40 am
content: I have this scope and it is an excellent and reliable piece of gear. If it is in good overall condition, you can't go wrong with it.Fortunately nowadays probes that easily exceed its specs can be found at a very cheap price on eBay.
Noob Power Supply Question - Page 1
Forum section: electronics / beginners

author: vargoal
author_rank: Regular Contributor
timestamp: December 26, 2014, 04:15:42 am
content: Hi EEVBlog,I am a high school student interested in becoming a computer engineer. I am thinking about making a software controlled power supply. Because I am a fan of EEVBlog I immediately recalled the uSupply video series. I also wanted to mod the design a little bit because hay i'm an engineer. I downloaded the Rev C Schematic from the forum(http://www.eevblog.com/files/uSupplyBenchRevC.pdf) I want to add a atmega328 and an IR receiver so I can adjust the supply from my phone which has a IR transmitter. I was wondering if i could drive transistor Q2 on the schematic directly from my microcontroller which is measuring the current with the INA219 chip. I realize i will gain a little noise and it probably will not react as fast but i think the 16 MHz of the atmega328 i plan to add will be enough for my needs. One reason I am trying to drive the transistor directly is that I want to reduce the number of parts. Do you think this will work? Any advice for a future computer engineer would be appreciated. Also any ideas for other changes to the uSupply would be great.

author: Christopher
author_rank: Frequent Contributor
timestamp: December 28, 2014, 06:55:49 am
content: Try controlling an LM317 with a micro first. Then add bits.Baby steps!
Feedback/Question about electronic load design... - Page 1
Forum section: electronics / beginners

author: bollio
author_rank: Contributor
timestamp: July 09, 2016, 02:52:20 am
content: Okay, so like every other noob out there, I'm building my own electronic load. Loosely based off good ole' Dave's lm324 design, but I'm trying to make something of my "own." You know, learn a little bit as I make mistakes. I've got a couple questions and/or requests for feedback. Essentially I'm looking for something with mA accuracy and nothing more.First, attached is my rough chassis mock-up for the electronic load... a little bit of a Frankenstein/50's vibe and I've got a vintage Bakelite radio tune dial coming in the mail I'll be mounting on the top to adjust the load. The heatsink is recycled from an old 80's receiver... anyone have any rough ideas as to what kind of wattage (estimate of course) this thing could handle? It's got a .5" heatpipe mounted in an aluminum block (not pictured but it's about 1" x 4" x 3") and each of the plates are probably 1mm thick and 4" square. Figured that this would be kind of important, given I'm planning on using a a pair of mosfets capable of 190watts each. Meaning, I believe that the limiting factor on what kind of amperage the load can handle will be the heat sinks ability to dissipate the heat!Also, some input on the circuit would be nice as well. I've come across some op amps that I'm thinking of using, but am unsure as to their suitability. They're not bipolar op-amps, but rather CMOS op-amps. LMC662 rail to rail op amps to be exact. Now from everything I've read, it seems as though it'll "work," but CMOS op amps tend to be a bit noisier, suckier at lower bandwidths, and have worse input offset voltage. That said, it's a home made electronic load and most likely won't be a precision piece of gear... will these issues be overly detrimental to my build? I do have some TL082's or TL741's (I realize everyone seems to hate these anymore) that I could use instead.Also, I've read quite a bit about running multiple mosfets to share the load and will probably be using the aforementioned tandem mosfets. Some sources say parallel is bad idea, others say just match the mosfets, many say each needs it's own op-amp. I was planning on running each off their own op amp, sense resistor sets, and a tuning pots for each to even out any differences in output, but I'm not really sure that it matters all that much as long as I can see the total combined load. I guess I'm a bit hung up on the question as to if it's more precise to replicate a single load on a power source or parallel loads on the power source.

author: Atree
author_rank: Newbie
timestamp: July 10, 2016, 05:24:08 am
content: fans make a hell of a difference. just keep in mindSent from my iPhone using Tapatalk

author: bollio
author_rank: Contributor
timestamp: July 10, 2016, 03:08:11 pm
content: Yea the chassis will have a couple of 80mm fans in taking from the back. I figure it'll cause enough positive pressure in the chassis to creat airflow over the heat sink... We'll find out I suppose!
noob question: function generators - Page 1
Forum section: electronics / beginners

author: outofstepper
author_rank: Contributor
timestamp: June 07, 2012, 02:10:24 pm
content: Ok, this question might get a lot of eyes rolling and/or tears from laughter.. but herewe go..Entry-level FG ($$$) vs. 555-based shoebox FG (~free)used for learning / eventually debugging broken stuff.So i won't be getting the freq range / stability / accuracy / ease-of-use of a pro unit.. understood..but what I'm not quite so sure about is if I'm starting out with both hands tied behind my backbecause of any (obvious?) limitations I might not be aware of.Thoughts?and thanks!Tony

author: Bored@Work
author_rank: Super Contributor
timestamp: June 07, 2012, 02:21:11 pm
content: What do you have to lose? If you think the free 555 shoebox will do, then start with it? While using it you can save more money to buy a real generator, and learn things the hard way. Aka the school of hard knocks.

author: Lightages
author_rank: Unknown
timestamp: June 07, 2012, 02:40:21 pm
content: As long as you can get a decent sine wave out of the shoebox parts then I second the post above.

author: T4P
author_rank: Super Contributor
timestamp: June 07, 2012, 03:28:52 pm
content: One should simply start off with building his/her own "555" based Sig Gen, thy learns more that way

author: hlavac
author_rank: Frequent Contributor
timestamp: June 07, 2012, 10:32:53 pm
content: How about something designed for the job, likeXR2206? Do they still make them? Or are there any modern alternatives?In fact, as a pure electronics hobbyist, I'm missing a function gen too! Maybe we could design one together?

author: MikeK
author_rank: Super Contributor
timestamp: June 07, 2012, 10:41:49 pm
content: Before I bought my Instek I was considering this:http://www.electronics-diy.com/store.php?sel=kits&sub=function_generatorOnly $40.

author: Barryg41
author_rank: Contributor
timestamp: June 07, 2012, 10:56:16 pm
content: I ordered and put this kit together to mess around till I decide on a proper FG.http://www.kitsusa.net/phpstore/html/Elenco-FG-500K-1MHz-Function-Generator-Kit-5974.htmlWorks for me right now!

author: outofstepper
author_rank: Contributor
timestamp: June 08, 2012, 01:20:08 pm
content: Thanks guys.That kit from electronics-DIY looks interesting and I'll likely pick it up.-- two minor points though (not complaining!), the freq range selectoris pcb mount dip switch so if I wanted to put this in a nice case I'd have to find a selector switch(I assume only 1 of the four pins goes high to select). Second, the freq counter kit is nice too butresolution in 10Mhz steps.Beggers being choosers? Maybe.Thanks again!Tony

author: caroper
author_rank: Regular Contributor
timestamp: June 09, 2012, 08:47:41 am
content: Quote from: outofstepper on June 08, 2012, 01:20:08 pmBefore you do take a look at this one:http://www.changpuak.ch/electronics/FG2206.phpI am not sure if there is a kit, but it is very well documented.Look under Project Details on the Right below the clock.CheersChris
Noob question,  HD SDI MAIN - Page 1
Forum section: electronics / beginners

author: Seaofdep
author_rank: Regular Contributor
timestamp: July 16, 2017, 05:44:29 pm
content: Hi, i have tried to find information or how to on this HD SDI MAIN. It's for a security dome camera project I am piecing together one part at a time. My thought is the rj45 is for the rj45 to bnc, power cable , but not sure what the other two connections are for. I was wondering if anyone can help me understand the connections, and what connects to what.
NOOB Question - Unknown component?? - Page 1
Forum section: electronics / beginners

author: paul_g_787
author_rank: Frequent Contributor
timestamp: April 04, 2021, 03:53:27 pm
content: NOOB Question time. Does anybody know what this component is?It is in parallel with the mains 240V power switch of this guitar amplifier - a Dean DGX15.It is labelled either SC103Z2D or SC10372D

author: Benta
author_rank: Super Contributor
timestamp: April 04, 2021, 03:58:59 pm
content: MOV or metal-oxide varistor for voltage spike protection.Could also be a capacitor, but the blue color makes it less likely.

author: paul_g_787
author_rank: Frequent Contributor
timestamp: April 04, 2021, 05:48:18 pm
content: Quote from: Benta on April 04, 2021, 03:58:59 pmIf it were a MOV, wouldn't it be in parallel with the transformer primary coil like this?This one is in parallel to the power switch. Please see attached schematic.This is what doesn't make sense to me...Perhaps the amp is assembled incorrectly? I don't like how the fuse is not the first component in the circuit...

author: Nusa
author_rank: Super Contributor
timestamp: April 04, 2021, 06:14:16 pm
content: I don't think it's a varistor. I think it's an arc suppression capacitor, intended to reduce speaker popping when you operate the switch.

author: Benta
author_rank: Super Contributor
timestamp: April 04, 2021, 06:22:13 pm
content: I'm with Nusa, and that was also my second suggestion.But due to the meagre information in your first post... well...

author: BrokenYugo
author_rank: Super Contributor
timestamp: April 04, 2021, 06:31:16 pm
content: 10 nanofarad X1 safety cap? I think that'd reduce the RFI pop from the switch?
Noob question: What is this component? - Page 1
Forum section: electronics / beginners

author: Prithul0218
author_rank: Contributor
timestamp: January 25, 2019, 03:33:04 pm
content: It looks like a capacitor. But 3 pins?I found it on a brushless motor ESC.

author: Benta
author_rank: Super Contributor
timestamp: January 25, 2019, 04:32:14 pm
content: Ceramic resonator for clock generation.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: January 27, 2019, 10:04:34 am
content: I'm not too sure about that component being a ceramic resonator.Those are usually a lot smaller.It could be an unusual ceramic low voltage capacitor, or 2 capacitors in 1 SMD package.If you follow the PCB traces you know for sure.If it is connected to Vcc it is a capacitor.If it is connected to the oscillator pins of the uC it is a ceramic resonator.

author: westfw
author_rank: Super Contributor
timestamp: January 31, 2019, 10:14:25 am
content: QuoteNah; Arduino boards have been using especially tiny resonators, but a lot of them are much bigger.(also, that's not as big as it looks. Assuming 0.8mm pin spacing on the TQFP, it's 4 or 5mm long?)https://www.digikey.com/product-detail/en/abracon-llc/AWSCR-16.00MTD-T/535-9362-2-ND/
Noob Question² - Get an Custom Audio Board Manufactured? - Page 1
Forum section: electronics / beginners

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 20, 2024, 10:43:27 pm
content: HiI think about get an Custom USB - Audio Board Manufactured from Company who can deliver a ready PCB. I have a need for that what some Audio Recorder can do but I need them for "real Time" stuff. Long story short since Audio Chips are very Cheap this days also Storage I want place 3 Chipsets on an Board with one have an Audio Amp for weak Audio Signales, one without anything (maybe an Amp to get +/- 0Db Gain.) and one who have some kind of Variable Noise Reduction think sry when I dont know how to call it in English. At the end I will have 3 Channel for Signal Analyse who can handle weak, normal and high power Audio Signals Parallel.Why is that important? For example everyone here who use an Hight speed Train in good old Europe know when you use a Camera and you enter a Tunnel the Cam see nothing until the cam Adjust the Settings the same when you leave the Tunnel the Image is just white. With 2 or more Cams who are fix exposure the Cam see inside the Tunnel and the other see instant when you leave them and you dont loose any Information. The same for Sound. When there is a loud Bang and than someone whisper anything its hard to record it. With Multiple Soundcard, Input in Post I can adjust the Audio.For example that one:https://www.cmedia.com.tw/products/USB_AUDIO_CODEC/CM7030offer 2 Mic Inputs so I would just need 2 Chips + USB Hub Chip if I understand it rite.With ex "exposed" I2C Header it should be possible to set Settings that way no matter what OS i use? Rite?Do I have any flaws? Could that work?Thanks

author: oPossum
author_rank: Super Contributor
timestamp: May 20, 2024, 11:19:20 pm
content: There are audio interfaces and recorders that do this.https://zoomcorp.com/en/us/news/32-bit-float-everything-you-need-to-know/

author: Lord of nothing
author_rank: Super Contributor
timestamp: May 21, 2024, 06:53:01 am
content: I know but I need them for my Radio to Digitalise the Audio and process them. There should be no Light, Display or anything else.My Icom Adapter sadly support only a fix Audio Level with pysical Knobs.
noob questions about scopes [getting one soon] - Page 1
Forum section: electronics / beginners

author: prawncrackers
author_rank: Contributor
timestamp: February 17, 2016, 02:56:09 am
content: hello guys, a fan of dave's youtube stuff here! decided to join the mobive been an electronics enthusiast for a long time now. i saved up my allowance and i can now afford an entry level scope and looking at the Hantek DSO5102p at USD244 from Aliexpress please note that its all i can afford and i have a small customs tax to worry about. i have a few questions to ask before dropping my savings hehehe...1. so i was thinking id ask around here (more like to confirm), that theres nothing better than this scope at this price?looking at the datasheethttp://www.hantek.com/Product/Datasheet/DSO5000P_Datasheet.pdfit says the max input voltage with 1x probe is 150vrms(300vrms with 10x) regardless of software coupling, our mains is 220vacrms and oftentimes i work with my friends tube guitar amps with voltages reaching 450-500vdc2. so if i forget to toggle the 10x in the probe does this mean id instantly fry my "expensive" scope? this seems silly but i admit i make mistakes of sublime stupidity. my DMM has higher max voltage headroom so im not that worried.im thinking since i may not be able to afford a 100x probe soon, im thinking of making an L-pad attenuator/adapter (F-M BNC) from 1% MF resistors 9.9M + 100k (im even thinking of lower impedances like 990k+10k) for measuring high voltages. capacitance isnt really important for my HV purposes.3. is it a good practice to "permanently" have this adapter on and remove only when i need precision low-ish voltage scoping?4. i may be a bit paranoid but i think ill open it up and put sort of protection like a 200v DIAC or zener or the typical clamp diodes (ground to signal to vcc) but wont their capacitances affect measurement?5. ive seen dave's video on how not to blow up your scope. shorting voltages across the probe negative clamps through the bnc grounds, yeah, thats something i can see myself doing. is it possible or a good idea to put a fusible resistor or a ceramic fuse between the BNC grounds and its PCB connection?thanks for taking time to read my questions. it may not be much but im excited getting a scope and a frying scope isnt really a nice feeling and an exploding probe might trigger something inside the heads of my parents.
Noob questions regarding anti-static mats. - Page 1
Forum section: electronics / beginners

author: medical-nerd
author_rank: Regular Contributor
timestamp: November 28, 2017, 11:50:54 am
content: HiyaSo... I finally bought an antistatic mat, a couple of wrist straps and a mains earth bonding plug containing a 10Mohm resistor.A couple of questions - there is one connector on the mat, if I use this to connect to the mains earth via the bonding plug where do I connect the wrist straps - do I strip the cable connecting to earth and make extensions? or do I clip the crocodile clips directly to the surface of the mat?Is it safe to power up boards on the mat for testing - or will it be conductive enough to short out pcbs?Many thanks for any guidance.

author: jmelson
author_rank: Super Contributor
timestamp: November 28, 2017, 08:03:14 pm
content: Quote from: medical-nerd on November 28, 2017, 11:50:54 amUse an Ohm meter to check the resistance of the mat. with the probes a couple inches apart on the mat, you should get a resistance of 100K to a couple meg Ohms. You should also get a resistance of a couple meg Ohms from anywhere on the mat to the ground terminal or cord.If the resistance shows up as several meg Ohms, you can safely power most circuitry on the mat. But ultra-sensitive circuits or high voltage stuff can be affected.Jon
Noob trying to learn component level fault finding.  Panasonic TC-32x5 TV - Page 1
Forum section: electronics / beginners

author: guitchess
author_rank: Regular Contributor
timestamp: November 16, 2014, 06:19:25 pm
content: I'm trying to fix this dumpster dive TV without guessing and replacing whole boards. Someone else has tried that because the box that the set was found in contained an extra power supply board.Prelim details.1. When power is applied, nothing. No flashing LEDs, sounds, smells, etc.2. When opened, there are no obvious signs of damage. In fact, the set looks brand new.When I test voltage, the P board is supplying 4.3 volts on the standby pin when everything is connected. According to the service manual, it should be around 5.8v. When I disconnect the A board(main board in Panasonic terms), the P board output jumps to 6.5v. Which led me to believe that something on the A board was drawing too much current.On the A board, voltage stays at the 4.3v all the way to IC5000, which leads to my main question(for now). The two resistors in the partial schematic are shown to be 1% tolerance, and in circuit neither tests within spec(they are both more that 10% out). First, do you think is this situation that it would be necessary to remove them from circuit for an accurate read? They are so tiny I doubt I will be able to reinsert them if they are not the issue, that is, if I don't loose track of them as soon as they're out of circuit. Second, do you think that these resistors being lower than spec would cause the voltage to be lower than spec thereby not letting the set power on?The service manual that I am referencing came from here.http://www.csweb.lar.panasonic.com/viewing/NA/TC-L32X5/SVC/MTV1202010CE_PRINTDB/NEW_TC-L32X5.pdf

author: guitchess
author_rank: Regular Contributor
timestamp: November 16, 2014, 06:25:25 pm
content: FYI, the 22k tests in circuit as 19.4k and the 56k tests at 39.3k.
Noob With Agilent MSO-X 2024A - Page 1
Forum section: electronics / beginners

author: ItIsMe
author_rank: Newbie
timestamp: February 13, 2015, 02:12:21 am
content: Hi all! I'm a college student studying EE.I don't have much experience, and was playing around with our Agilent MSO-X 2024A scopes in the lab. I set a function generator to produce a 3kHz sinusoid with 5Vpp amplitude and 0V DC offset. But when I looked at the measurements on the scope, I was reading an amplitude of 7v.... These function generators are very precise, so I think the issue is with the scope. I think it is measuring amplitude as the difference between a peak and trough of the wave. How can I set the amplitude to be the distance from 0 to the peak? I heard this is a common "issue" with the scopes.I've tried google-ing things such as "Agilent 2024a calibrate amplitude" and other variations, but have so far not found a solution.Thanks!

author: w2aew
author_rank: Super Contributor
timestamp: February 13, 2015, 02:52:58 am
content: Quote from: ItIsMe on February 13, 2015, 02:12:21 amProbably a couple of things going on. The function generator is probably expecting a 50 ohm termination impedance and you have the scope set to 1Mohm input impedance which results in double the amplitude (see video below). Also, it sounds like you've selected an "amplitude" measurement which may be giving you the RMS value instead of peak-to-peak.

author: ItIsMe
author_rank: Newbie
timestamp: February 13, 2015, 03:41:11 am
content: Quote from: w2aew on February 13, 2015, 02:52:58 amAwesome!!! Thanks, that looks like the issue. I'll try it out tomorrow when lab is open.
Noobie oscilloscope question - Page 1
Forum section: electronics / beginners

author: LuisLDias
author_rank: Contributor
timestamp: October 10, 2015, 03:47:39 pm
content: Hi everyone!I'm a new member of evvblog forum. My name is Luis and I'm from Portugal. Sorry for my english.Today I has probing a tyhristor bridge rectifier at my college. When I probe the voltage of the tyhristor with my Uni-t UTD2052CEX the recovery peak voltage doesnt fit the screen with x1 probe. When I put the x10 the screen freezes and with the x1 the oscilloscope cant take any measure like averange or rms voltage.Is there any method to probe the tyhristor without seeing the recovery peak voltage?The Uni-t UTD2052CEX not worth the money.Once again sorry for my english. Please correct meChears

author: alsetalokin4017
author_rank: Super Contributor
timestamp: October 11, 2015, 12:50:23 am
content: Luis, your English is fine. You've made a couple of spelling errors but your grammar is good and your meaning is clear.Now... you would normally use 10x probe setting, on both the probe and in the scope's Channel menu, for your measurement. When you say "the screen freezes" when you use the 10x setting.... could this be because the Trigger voltage setting is now out of range of the signal you are measuring?If you can post a schematic of the circuit you are probing, and a screenshot of the scope, including the scope's settings, it may help us diagnose your problem.

author: JoeB83
author_rank: Regular Contributor
timestamp: October 11, 2015, 05:28:17 am
content: Like alsetalokin4017 mentioned, your English is fine. In fact, your English is a lot better than many native English speakers.As mentioned, taking a screen shot or making a quick video could be helpful.

author: LuisLDias
author_rank: Contributor
timestamp: October 12, 2015, 01:08:57 am
content: Tomorrow i will put some pics and schematics. But thanks for your kindnessLuís Dias