hybridfree/eevblog-posts huggingface dataset:
Need help decoding some diode (zener) and  - Page 1
Forum section: electronics / projects

author: Houseman
author_rank: Regular Contributor
timestamp: February 14, 2023, 11:59:26 am
content: Hi folks.I have dismantled in my cellar a circuit that controls hot water fluid through a solenoid valve, driven by electronics using PHASE-CUT method at 24V AC 10W controlled by 0-10V DC inputI have discovered that such method was used in the 90's to efficiently control solenoid valves now it is supeseded by way more efficient PWM method.The PCB got magic smoke and since there are no more spare parts available I need to repair it by myself rather than changing the entire valve that costs more than 2k..I want to study this circuit so I have reversed some part of it but I need some help to discover parts of the electronic.In the attachment you can see a black element (must be a capacitor labelled ERD 0,033 J - maybe a 33 pF ceramic capacitor? - my LCR tester cannot recognize it) and C1 a color coded ceramic capacitor that could be 27pF. correct me please if I am wrong.I am having troubles with the DIODES. Obviously all the components has been desoldered and tested separately. The picture is for reference only.One tester I have erroneously says they are all zener diodes all 8,7V. Could be maybe D9 ( blue color coded) since it has anode to ground and the cathode is connected in parallel to the electrolytic capacitor you can partially see top left. But what about the D14 green one?Another component tester says they are all normal diode with forward voltage of 0,7V and does not detect any reverse voltage of the zener.. maybe D10-D13-D15-D16 could be normal 1N4001.. I do not know how to find out.Could you please help decode the ring code? I have searched through the forum and found other threads but I guarantee there are no other rings nor letters on it. also by a microscope.Thanks a lot.Regards.Steve
Need help designing wireless charging coil - Page 1
Forum section: electronics / projects

author: Gladius
author_rank: Newbie
timestamp: November 18, 2019, 06:30:55 pm
content: I am planning on building a bit of a special bike light.Basicaly im tired of having to constantley change batteries and remembering to charge my bikes light.There are existing wireless solutions that work by having magnets mountet to the spokes of the wheel and a pickupcoil inside the bikes light. When the wheels turn the magnets move over the coil causing a current to flow and lighthing up some LEDs. Sadley those LEDs are nowhere near powerfull enought to be actualy usefull to see at night so I thought id desing my own solution. Same concept just a bit better. Mainley I'm thinking of using a 1W-3W LED and a backup battery that gets charged whenever you use the bike so the light output is stable and independent of speed.For the magnets I thought some strong neodymiums from aliexpress but I am not shure how I should aproach the coil.It should deliver about:4.5-5V @ 400-500mA@15Kmh. -> 115 rpm=2rps => v(magnet@0.3m from middle)=3.57m/sI was hoping to use industry standart parts such as coils for QI chargers to avoid having to make or order custom parts.If anyone could help me by pointing out:- Formulas- Things to know about designing such coils and associater electronics- Of the shelf parts I can useIt would be greatley apreciatet.Thanks for all the help.

author: SiliconWizard
author_rank: Super Contributor
timestamp: November 18, 2019, 07:53:44 pm
content: Are you sure you don't want to buy a dynamo hub instead?https://www.cyclingabout.com/best-dynamo-hub-bicycle-touring-bikepacking/

author: Gladius
author_rank: Newbie
timestamp: November 18, 2019, 09:23:31 pm
content: Haha yeah I know it would be much easier but since this is a joined venture with a buddy of mine who is a designer he turned down this exact question for lack of sex appeal and ease of use. So sadley not an option.
need help determining transistor manufacturer/brand - Page 1
Forum section: electronics / projects

author: natezaps
author_rank: Newbie
timestamp: October 03, 2020, 06:38:36 pm
content: I have 2 2N2369 transistorsOne of the transistors has a logo on it but I can't make it out. I have attached a photo. It says 2N2369 7326 AA (the 7 might not be a 7, it's faint)The other transistor has no logo and says 2N2369A 739 AAThey are both metal can and both have gold leads

author: PA0PBZ
author_rank: Super Contributor
timestamp: October 03, 2020, 06:56:03 pm
content: National Semiconductor

author: natezaps
author_rank: Newbie
timestamp: October 03, 2020, 07:03:03 pm
content: thanks!
need help electronic/relay problem phone horn - Page 1
Forum section: electronics / projects

author: georgebaker
author_rank: Newbie
timestamp: December 19, 2021, 04:53:24 pm
content: I need to ring a phone that activates a loud ass horn. Phone has no audio ports. I'd be tapping into the 2 wires that connect from phone circuit board to the phone ring speaker.Inside the handset, the 2 wires show .035-.045 VAC (probed with multimeter while the phone "rings") and connect to an 8 Ohm 2W speaker inside the phone. This 8 Ohm 2W speaker needs to be replaced with a very loud horn or buzzer.-I purchased a generic 12VDC piezo horn. Need to feed it 12VDC when phone rings. That's all.I'm stumped. Low signal relay? Some type of inline amp? I can solder a bit, and have only a very basic understanding of this stuff.Do I look for a low signal relay? like .03VAC to 12VDC?Thank you

author: madires
author_rank: Super Contributor
timestamp: December 19, 2021, 05:40:58 pm
content: Welcome to the forum! You'll find tons of circuits when searching for 'telephone ring detector'. There are also kits and COTS modules. Some telcos sell them too, especially for hearing impaired people.

author: Terry Bites
author_rank: Super Contributor
timestamp: December 21, 2021, 04:44:51 pm
content: https://circuits-diy.com/telephone-ring-detector-using-pc817-optocoupler/or just about any opto, small signal npn or mosfet here.Always use an isolater, ringing current can give you a painful shock.Make sure the relay contacts can handle the DC load current- use a car hooter relay.https://www.ebay.co.uk/itm/151808536651?hash=item23587e704b:g:cpQAAOSw3YZclOdo

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 21, 2021, 11:44:27 pm
content: All the ring detector circuits I have seen are for the old analog lines that have become uncommon many years ago. Pretty much every wired phone nowadays is VoIP. I would check the manual for the phone and the website of the manufacturer, it's a common problem for shop phones so most likely there's an off the shelf solution for it.
Need Help Finding A Replacement Encoder - Page 1
Forum section: electronics / projects

author: radiotek
author_rank: Contributor
timestamp: February 13, 2019, 02:07:48 pm
content: Need Help Finding A Replacement EncoderTrying to find a replacement mechanical encoder for a Sangean ATS-505 radio I own. The decoder is approximately 11 to 12mm square that's vertically mounted and has a total of 5 contacts, 3 for tuning up and down and 2 for a switch.Not sure how many detentes but I am sure that anything between 16 and 24 should be OK.Any help would be greatly appreciated.

author: MarkF
author_rank: Super Contributor
timestamp: February 13, 2019, 02:16:56 pm
content: Looks like the ALPSEC11B15242AZwould work.
Need help finding boost converter - Page 1
Forum section: electronics / projects

author: jamessinghal
author_rank: Contributor
timestamp: April 21, 2017, 07:40:16 pm
content: I have a 60v 15 amp ac dc linear power supply that I built, and I want a good, efficient way to be able to adjust the voltage and current.All I have found is a boost converter, but it has a low point of 12v, and that is unsuitable for by needs, as I need a max low point of 1.5vI you have a good solution, I would love to hear it.

author: Zero999
author_rank: Super Contributor
timestamp: April 21, 2017, 08:04:10 pm
content: Quote from: jamessinghal on April 21, 2017, 07:40:16 pmYou've not made your requirements very clear.What's the boost converter got to do with the linear regulator? Are they related projects, or are you just mentioning your previous experience?60V at 15A is 900W of power. A boost converter to convert 1.5V to 60V at 900W would need to take 600A from the 1.5V power source, assuming 100% efficiency. In real life there will be losses, so the current will be much higher.

author: jamessinghal
author_rank: Contributor
timestamp: April 21, 2017, 08:07:04 pm
content: All I need is a way to limit the current and the voltage, the efficiency doesn't matter to me.

author: Zero999
author_rank: Super Contributor
timestamp: April 21, 2017, 08:08:56 pm
content: Quote from: jamessinghal on April 21, 2017, 08:07:04 pmThen the title of the thread is misleading. You do not need a boost converter at all, but a way of varying the voltage and limiting the current! Is that correct?

author: anman
author_rank: Contributor
timestamp: April 21, 2017, 09:22:57 pm
content: You need a Power Buck Converter Step-Down ModuleDC-DC

author: jamessinghal
author_rank: Contributor
timestamp: April 21, 2017, 10:14:05 pm
content: Quote from: Hero999 on April 21, 2017, 08:08:56 pmI said this because a boost converter was the best way I knew how to do this

author: Zero999
author_rank: Super Contributor
timestamp: April 21, 2017, 10:51:28 pm
content: Quote from: jamessinghal on April 21, 2017, 10:14:05 pmYou will not achieve this with a boost converter, which increases the voltage and decreases the current.It would be better to modify your existing linear power supply to vary the output voltage and limit the current.Do you want to build a 1.5V to 60V power supply with an adjustable current limit?

author: jamessinghal
author_rank: Contributor
timestamp: April 22, 2017, 02:03:40 am
content: Yes, thanks!That is exactly what I am looking for, and if you have a better way than just buying a cheap chinese circuit to adjust voltage and limit current, that would be greatly appreciated.
need help finding NEC part - Page 1
Forum section: electronics / projects

author: KTP
author_rank: Frequent Contributor
timestamp: January 26, 2011, 10:05:05 pm
content: Hi guys,I was tinkering around with an Adept EXC standalone controller for robot linear modules, trying to communicate with it via RS232. I built the correct cable for the teach port and I have it spitting out the startup information to a pc terminal program, but I can't managed to send any commands to it. The command 8F is supposed to put it in teach mode but it does nothing. I am guessing the problem is the RS232 receiver chip is blown (could have gotten static zapped by previous owner(s) ). I took off the cover and see that the 9 pin serial port leads to a NEC chip part number D4711AC. This is a 20 pin narrow DIP chip surrounded by four 22uF caps. I did some searching and finally found a data sheet from NEC for a uPD4711B, which I am pretty sure is the same part. I can't seem to find any supplier of this part or a drop in replacement from Maxim or ST or someone. Anyone just happen to know of one offhand?

author: KTP
author_rank: Frequent Contributor
timestamp: January 26, 2011, 10:38:58 pm
content: Ok, I used my trusty Rigol to determine that indeed the transmissions from the computer terminal program RS232 are not making it through the NEC D4711AC chip from pin 13 to pin 8. When I send a char I can see a burst at pin 13 and I see nada at pin 8. Diagnosis, blown chip. Now, the question is, exactly how obsolete and hard to find is this part? I guess I could hack in a daughterboard with a Maxim chip...ugly.Here is the data sheet I found:

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 26, 2011, 11:03:24 pm
content: Probably easiest to just bodge in a more available RS232 transceiver than hunt down an obscure one. If you want it neat, put a SMD trasceiver on a DIP carrier PCB.

author: KTP
author_rank: Frequent Contributor
timestamp: January 26, 2011, 11:27:36 pm
content: Quote from: mikeselectricstuff on January 26, 2011, 11:03:24 pmYa, I agree with you. I found an old board that has a 14 pin Max1489 on it. Since 3/4 of the NEC chip is still working, I could just dead bug glue this 1489 on top of the old chip and carefully cut the offending receiver line leg of the NEC chip and bypass that buffer with the 1489. Hopefully nobody will peek inside and see the nastiness.
Need help finding out what this circuit does. - Page 1
Forum section: electronics / projects

author: Frazatto
author_rank: Contributor
timestamp: October 28, 2020, 01:26:47 pm
content: Ok, long story short, I'm trying to reverse engineer an undocumented IC from Yamaha (YM7108 from a PSS-20 toy keyboard), I made a good job so far but there are two pins I have no freaking idea what they are supposed to do!You can check it out here:https://www.eevblog.com/forum/beginners/looking-information-on-ym7108-ic/msg3198836/#msg3198836I recently took the time to trace the sound interface and discovered what pin 17 does, it's sound + (there doesn't seam to be a - channel), but if I try to generate sound using it, it just floods ground with the pwm signal and creates havoc on everything else (like detecting key presses). This happens because of the keys common ground and the pull down resistors I had to solder for each of the 6 input pins.So I wander if those two pins doesn't have something to do with it (how to solve this problem), I mean, the YM7108 had to deal with this some how, right?They are connect to ground and each other using a strange capacitor configuration (small, one in line for each and one crossing) before going to ground:14------| |------ --------GRN________15------| |------ --------GRNIf anyone recognizes this configuration, it could give me a clue for what the pins were used for originaly.Any help will be appreciated!
need help finding seller/distributor of heat sink - Page 1
Forum section: electronics / projects

author: ttyridal
author_rank: Contributor
timestamp: April 02, 2019, 08:58:41 am
content: A lot of marine/automotive electronics is delivered in this type of heatsink (pic) leading me to think this is some standard type.Unfortunately my searching skills are unable to locate a seller / distributor. Does anyone know where these can be found / bought in "hobby quantities"?Cheers

author: ttyridal
author_rank: Contributor
timestamp: April 02, 2019, 12:35:28 pm
content: Never mind.. I was fooled by the "end plates". For some reason I've been thinking they where an integrated part of the heat sink
Need help finding the cause for a feedback loop - Page 1
Forum section: electronics / projects

author: workbench
author_rank: Newbie
timestamp: May 20, 2019, 10:01:12 pm
content: Hello Everybody,this is my first post.I ported the hihat section of a Roland TR606 for Eurorack synthesizer to a PCB.At the first test, the Hipass Filter began to oscillate on the last quarter of the potentiometer (CW). It lies in the area B6 in the attached PDF.I have already tried to add 220pF capacitor in parallel with the potentiometer, unfortunately unsuccessful.Maybe you can give me a hint why it could be.ThanksMarkus

author: dmills
author_rank: Super Contributor
timestamp: May 21, 2019, 12:26:58 am
content: Check the value of R48, 52-55.You have an opamp configured for a gain of -2, and some positive feedback. To a first approximation if the gain between the opamp output and its non inverting input exceeds a magnitude of 0.5 you are asking for the thing to take off.Looking at it I am having a slightly hard time seeing how it could be stable, the analysis is not straightforward, but I am seeing a LOT of positive feedback when only R53 is in play. Check your values, I suspect a dropped decimal point somewhere or other.Incidentally, if that little cap was going to help stability it should have gone across R54 IMHO.

author: workbench
author_rank: Newbie
timestamp: May 21, 2019, 03:00:12 am
content: Thanks a lot.I swapped r53 for 12K. I have no oscillations anymore
Need help fixing DELL motherboard, (schematic here) - Page 1
Forum section: electronics / projects

author: zaoka
author_rank: Frequent Contributor
timestamp: March 17, 2013, 09:12:02 pm
content: DellN7110Symptom: dead, no powerOn page 36 there is a controller PU12. It provides 3 voltages:+5V_ALW_2 This voltage is always ON, its like standby voltage. It works fine.+3.3V_ALW Once AC adapter is plugged in, 3.3V works for about 2-3 seconds and goes off.+5V_ALW Same as 3.3_ALW, works for about 2-3 seconds.Pin 14 and 27 is used to enable these voltages. If logic level is high voltages should be fine.The problem is that I have pin 27 high all the time, however, +3.3V_ALW is present for only 2-3 seconds.I am about to order this IC and replace it.I just wanted to see if there is anything else that I should check before ordering...Motherboard schematic:http://goo.gl/sC2NFPU12 controller datasheet:http://goo.gl/JWGR6

author: Niklas
author_rank: Frequent Contributor
timestamp: March 17, 2013, 10:01:08 pm
content: Do you have an oscilloscope? If so, check if the controller does some switching at all during power up at the midpoints between Q1-Q3 and Q2-Q4. If there is switching activity that end, then it might be some current limiting that kicks in. Check for faulty loads.

author: zaoka
author_rank: Frequent Contributor
timestamp: March 17, 2013, 10:17:09 pm
content: No scope... (sold last month)I connected power supply and there is no current overload. Without CPU and memory it has around 200mA on each.Also I dont see that this IC is using current limiting feature...

author: nctnico
author_rank: Super Contributor
timestamp: March 18, 2013, 01:16:01 pm
content: Replace the CMOS battery. If that is dead, many motherboards won't start.

author: az113
author_rank: Newbie
timestamp: March 20, 2013, 12:17:20 am
content: Here is a many things in repairing notebooks...Do you check PL10 and PL11 to the ground for short-cirquit? May be it is a trouble?Also, double re-check, if the firmware in SPI flash is correct. (if you have an SPI programmer, i recommend you to re-flash a firmware (Backup of existing dump is strongly recommended!!!)
need help for arduino scope - Page 1
Forum section: electronics / projects

author: lightbringer81
author_rank: Contributor
timestamp: November 04, 2013, 03:49:05 pm
content: i was trying to make an arduino oscilloscope for fun i did the one in this website(http://www.homebrew-tech.com/arduino/brewing-arduino-announcement/usingarduinoasoscilloscope-arduinoscope)but when i tried to compile it said BYTE is no longer supported use Serial.Write() and i knew i just cant cut and paste that to therei also triedhttp://www.instructables.com/id/Arduino-Oscilloscope-poor-mans-Oscilloscope/but after i did all work when i tried to see waveform it just didnt do anything but a red linecan anyone help me for this please ? you can help me with code or 2nd with or it would be great if you link me a working one thanks all :=)

author: lightbringer81
author_rank: Contributor
timestamp: November 04, 2013, 05:53:43 pm
content: anyone ?

author: Jon86
author_rank: Frequent Contributor
timestamp: November 04, 2013, 06:45:10 pm
content: A bit more information would be good, we won't be able to help if you just say it doesn't work.Give us some code, schematics, pictures, then maybe we can help

author: kfitch42
author_rank: Frequent Contributor
timestamp: November 04, 2013, 07:04:01 pm
content: http://bit.ly/17Icu4khttp://www.engblaze.com/changes-in-the-arduino-1-0-release/

author: lightbringer81
author_rank: Contributor
timestamp: November 04, 2013, 07:11:02 pm
content: Quote from: Jon86 on November 04, 2013, 06:45:10 pmfor first one: after i put all libraries and sketches to both arduino ide and processing i ran and upload the code on arduino but processing which should run the UI on my pc said BYTE no longer usablesecond: in this one i upload all codes on both ide i ran them both when i touch the probe into a signal i wasnt able to see anything but a red linei ll try replacing byte as show in that link thanks for help

author: lightbringer81
author_rank: Contributor
timestamp: November 04, 2013, 07:32:41 pm
content: and by the way i can run codes in processing showing error " The function readStringUntil(int) does not exist// handle serial datavoid serialEvent(Serial p) {String data = p.readStringUntil(LINE_FEED);if (data != null) {// println(data);vals = int(split(data, ' '));}}
NEED HELP FOR CURRENT MEASUREMENT... - Page 1
Forum section: electronics / projects

author: BHARGAVSHANKHALPARA
author_rank: Newbie
timestamp: December 09, 2013, 08:12:03 pm
content: Hello everyone i need help in my project...Actually i made one control circuit which control one 1HP motor. its working fine but i added one extra function which is over current protection. for current measurement i used current transformer. i used ATTINY88 microcontroller for whole project. i decide to use ADC of microcontroller for current measurement.My current transformer ratings are as below...Primary winding turns : 1 turn of 2 wire (17 SWG wire).Primary Resistance : 0.01 ohmPrimary inductance : 3.72 uHSecondary Winding Turns : 350 turn of 36 SWG Wire.Secondary Resistance : 32 ohmSecondary Inductance : 380 MHafter obtaining output from secondary i used signal conditioning circuit link attached below...https://www.crmagnetics.com/Products/Assets/ProductPDFs/Precision%20Rectifier%20Circuit%20for%20CT%20Signal%20Conditioning.pdfin above document i used burdan resistor R1=100 ohm, zener diodes of 5.1 volt, as mention in document R2 should be at least 10 times so R2= 10 * R1R2=1Kalso mention in doc that R2=R3 Should be equal so i used both R2=R3=1K.For amplification i used R4=R5=22K.Diode at output of each op amp i used 1N4148.and at last FOR Filtering of output R=100 ohm and capacitor C=10uF.When i test my microcontroller circuit in simulator for particular value of ADC its work fine but when i do it in real circuit at particular value of ADC circuit not give exceat response(of course i connect AVCC AND GND WITH VCC AND GROUND IN PRACTICAL CIRCUIT RESPECTIVELY). also another problem is that when i pass 5.5 amp current from primary i get some value after signal condition but when i double, mean connect 10 amp load there is minor change in value (in some points only). means CT is not giving LINEAR response...!!i dont know whats going on...is there any problem in my value of signal conditioning circuit or any other thing is wrong...!!please help me to solve my problem...!!Thanks in advance...!!

author: Psi
author_rank: Super Contributor
timestamp: December 09, 2013, 10:04:45 pm
content: I've seen this issue before (non linear CT output) but i was just playing around with current measurement for fun and didn't really care to investigate.(Made up a system to measure the current of 50 power strips (multiboards) for a computer gaming LAN so we could display power stats per table)I wasn't concerned with fixing the problem so i compensated for the non-linear response with a function inside the MCU. I believe the reason for it, at least in my case, was non-ideal CT core material.I used some random cores i found and i'm pretty sure they saturated at high current which deformed the response. The response i got was pretty good up until 3A but started to ramp up after that and got really bad above 8A.What core material are you using?This is the raw response i got from the CT amp -> ADC input (after software rectification and RMS conversion).Response after software correction (Corrected ADC value vs CT current)The CT circuitCT core and sensor board
Need help for finding best way to isolate BNC connector from test shield - Page 1
Forum section: electronics / projects

author: sean87
author_rank: Regular Contributor
timestamp: January 12, 2012, 01:28:32 pm
content: For my project, I need to have BNC connectors on the test metal shield. So what I did so far is drilling holes, and mounting BNC connectors on it:I used some hot shring on the part which passes through the hole. Those washers are normal fibre ones. I don't have something better at my arsenal now. This will not be a good insulator, because I measured the resistance from outer bnc connection to the metal shield and it happend to be around 1.4 GOhm:The problem is, the signal LO (the outer connector of coax cables) should be totally isolated from the metal shield. The best thing I can think of is some sort of teflon washer (shoulder washer) that can pass through the hole of the metal shield and then I can insert the BNC connector through it. Unfortunately I was unlucky to find what I need. What I have found is made from nylon and I think it can not provide a resistance as good as teflon, also it has the problem of absorbing water (humidity) :Please let me know what you think, and would be nice if you know a place that I can order the required stuff!Regards,Sean.

author: wkb
author_rank: Super Contributor
timestamp: January 12, 2012, 01:39:13 pm
content: The best solution is to use BNC connectors with plastic isolation housing that is part of their design. I have some here, would need to go find them for a picture.This way you do not have to figgle with insulation rings and whatnot

author: jimmc
author_rank: Frequent Contributor
timestamp: January 12, 2012, 01:40:11 pm
content: Ready made insulated sockets are available e.g.http://uk.farnell.com/jsp/search/productdetail.jsp?SKU=1169702Jim

author: sean87
author_rank: Regular Contributor
timestamp: January 12, 2012, 02:31:32 pm
content: Yeah haha I didn't know that you can get them already isolatedThe one Jim linked has "ABS" as insulator. I found this one that has teflon as insulator:http://nl.farnell.com/jsp/displayProduct.jsp?sku=1205963&action=view&CMP=GRHB-OCTOPART-1002358I am confused by two properties of this connector:1- Insulation Resistance: 5000Mohm2- Outer Contact Resistance: 1mohmCan someone please confrim which of these values are for insulation between the connector and mounting shield? I guess it is the first one, if so, what is the second one referring to?Thanks.

author: sean87
author_rank: Regular Contributor
timestamp: January 12, 2012, 02:38:22 pm
content: Damn of course the second one is mili ohm
Need help for IR2110 at 500Khz - Page 1
Forum section: electronics / projects

author: rdpdo
author_rank: Contributor
timestamp: October 28, 2020, 08:32:55 pm
content: Hello all,I would like to use a IR2110 at 500Khz, and I found some informations about how to use it here :https://tahmidmc.blogspot.com/2013/...howComment=1603911775348#c2042051763996131553However, the values of the capacitors used for bootstrap are done for few 100th of Hz to 50kHz. For 30-50Khz, values must be between 4.7uF to 22uF.Does anyone has a idea of the values I must use for 500 Khz ?Thanks in advance.Regards.

author: drvtech
author_rank: Regular Contributor
timestamp: October 28, 2020, 09:41:16 pm
content: There's a formula in the application note herehttp://www.farnell.com/datasheets/2254418.pdfPage 5

author: rdpdo
author_rank: Contributor
timestamp: October 29, 2020, 10:00:35 am
content: Thanks you

author: Miyuki
author_rank: Frequent Contributor
timestamp: October 29, 2020, 11:50:51 am
content: OT question: will be IR2110 fast enough for 500Khz? It is not some super fast drive

author: rdpdo
author_rank: Contributor
timestamp: October 29, 2020, 12:33:59 pm
content: In the app note they say that it work very well without too much heating at 500khz.. But if you know other wich are designed for this speed I would like to know it :-) thank !
Need help for my project - Page 1
Forum section: electronics / projects

author: NathansElectronics
author_rank: Newbie
timestamp: October 23, 2024, 07:16:10 am
content: Hi everyone,I'm an electronics beginner and I'm starting a project. I want to do a computer mice. I've done the schematic but I'm not sure that everything is all right. So if any of you guys would take some time just to check my schematic and correct me if there's any need, I would highly appreciate it !My project is based on the open sourced project of wareya, here is his video :I kept the same MCU but changed pretty much everything else.I've done a small pdf with my schematic and explanations of it.After this I will develop the PCB, then command it, and finally develop the firmware.I’m open to all suggestions and I want to learn.thank for your time !Nathan

author: Terry Bites
author_rank: Super Contributor
timestamp: October 26, 2024, 10:33:40 am
content: The sensor and coms are usually integrated into one ic eg PAW3515.https://www.aliexpress.com/item/1005001804659170.htmlThe mechanical design will be the greater challenge.
Need help from analog gurus. 78L08 output at -0,9V - Page 1
Forum section: electronics / projects

author: dmg
author_rank: Regular Contributor
timestamp: February 11, 2015, 04:38:52 pm
content: I have a problem with a prototype circuit I had to rush in a week. It pretends to be a dual channel very high quality audio DAC with some requirements for distortion, flatness and bandwidth. I based it on the PCM1794A (http://www.ti.com/lit/ds/symlink/pcm1794.pdf) from Texas Instruments using a slight variation of the proposed output buffering circuit in the datasheet page 20(uses LT1028 as differential amp and a couple of NE5534 as IV converters for each output).We use a triple channel switchmode PSU (that switches at 110 kHz) to power the whole system (it must fit in a 1U rack case and height is too constrained for a linear PSU) with +5V, +12V and -12V rails. In the DAC board the +-12V rails are LC filtered and post-regulated using 78L08 and 79L08 regulators to the +-8V that feed the opamps of the oputput stage. They're decoupled using ceramic caps (and i'm aware it might be part of the problem). The 78L08 is TI branded (ua78l08) and the other is MCC brandedThe problem comes when we power up the board. The -8V rail gets to -8V without any problem but the +8V one goes to -0,9V and stays there. Then, if you unplug the -12V rail the +8V rail goes up to spec and stays there. Then if you re-plug it the -8V rail goes up and both rails stay up and the thing runs until you power the board off. We've red-necked the issue adding a delay switch in the -12V rail so it only powers the board once +8V are present but this must be turned into a commercial product in about a month and I'd rather solve the issue than patch it.Any clues about what may be happening? Something should be pulling the +8V rail negative until it reverse-biases a transistor in there preventing regulator startup, hence suspiciously staying at -0,9V, but I don't know how to solve the issue right now and i'm a little intoxicated with soldering fumes to think. Any clues?

author: wraper
author_rank: Unknown
timestamp: February 11, 2015, 04:47:06 pm
content: Likely, during power up 78L08 output gets pulled below zero and IC stops work correctly. Add reverse voltage protection diode like on the picture.

author: dmg
author_rank: Regular Contributor
timestamp: February 11, 2015, 05:19:27 pm
content: Bingo, thank you very much.
Need help getting a 1.77'' ST7735 TFT display to work with ESP32-S3 - Page 1
Forum section: electronics / projects

author: Hague Tech
author_rank: Contributor
timestamp: July 07, 2025, 02:13:29 pm
content: I have connected a 1.77'' ST7735 TFT display to an ESP32-S3 but when I try to test the display it simply flickers on and off and does not display anything. I have tried different libraries and changed various settings (initialisations like blacktab greentab etc. I have changed SPI speed and pin allocations) but they all yield the same result. I am using the Arduino IDE with the Adafruit ST7735 and the TFT_eSPI library. I have included the schematic of my PCB and the datasheet for the display unit. Any help will be appreciated.Also, the MCU is working fine, I have tested it with a basic LED blink program.

author: Buriedcode
author_rank: Super Contributor
timestamp: July 07, 2025, 09:05:39 pm
content: The next tihng to test is the SPI port/library/code. Preferably with a logic analyzer, but failing that, any other SPI device. That should at least tell you the pins are correct and the hardware SPI module is working. That won't tell you if the tft library is using the SPI port correctly - only way to know that is to see the data coming out of it.Don't see your schem in your post, only the datasheet for the display. Did you use the example code form the Adafruit library?

author: mazurov
author_rank: Frequent Contributor
timestamp: July 07, 2025, 09:55:09 pm
content: This code ->https://github.com/peterhinch/micropython-nano-guiworked with my esp32-st7735 combo. It is also very well documented, you may want to use it as a reference.

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 07, 2025, 10:08:16 pm
content: A large but very universal U8g2 library works with almost all displays. It distinguishes them somehow automatically. It helped me when I couldn't work with some small, unknown 1.30" SH1106G/SSD1306 display.

author: Hague Tech
author_rank: Contributor
timestamp: July 08, 2025, 09:22:09 am
content: Quote from: Buriedcode on July 07, 2025, 09:05:39 pmMust have forgotten to attach the schematic, here it is.I dont have a logic analyser and not sure if I could connect one anyway seeing as I dont have any headers on my board, it is a custom PCB with the display connected directly to the ESP32. I tried using example codes from the Adafruit and tft libraries, the only thing that happens is the backlight turns on and off. I think it is turning on and off when it should be displaying graphics but I will need to write some code to test that.

author: Hague Tech
author_rank: Contributor
timestamp: July 08, 2025, 09:24:55 am
content: Quote from: Vovk_Z on July 07, 2025, 10:08:16 pmThanks, I think this library is only for monochrome displays and does not include the ST7735.
(New photos added) Need help identify LCD panel connector type - Page 1
Forum section: electronics / projects

author: Logan
author_rank: Frequent Contributor
timestamp: September 14, 2021, 01:04:32 pm
content: Hi guys.Anyone knows what type is this connector? Are there any IPS panel can work on this?It seems have 32 pins, but are all 32 pin connectors compatible in protocol?Thanks.

author: Gribo
author_rank: Frequent Contributor
timestamp: September 14, 2021, 04:14:52 pm
content: Measure the contact pitch, this one looks like 0.5mm, but it can be also 0.4 or 0.635mm.Also, there are top or bottom contact option, check which one is yours.

author: jpanhalt
author_rank: Super Contributor
timestamp: September 14, 2021, 08:26:21 pm
content: Quote from: Logan on September 14, 2021, 01:04:32 pmWhat protocol? Please give a link. There is no requirement that all the tracks in a cable be connected.

author: james_s
author_rank: Super Contributor
timestamp: September 14, 2021, 08:55:23 pm
content: The type of connector used does not indicate anything about the type of interface, there is no standard.

author: coromonadalix
author_rank: Super Contributor
timestamp: September 14, 2021, 11:58:25 pm
content: surely not always the same protocol or the same pinout, the only way to know is to find the lcd part number and or finding the specs of the driver chip : graphical ot text generator / driver chip if the lcd doesn't come with it ...

author: MegaVolt
author_rank: Frequent Contributor
timestamp: September 15, 2021, 09:42:57 am
content: FFC/FPC connector

author: Logan
author_rank: Frequent Contributor
timestamp: October 18, 2021, 04:20:34 pm
content: I took more photos of the driver board(1,2) and a mark on back of LCD(3).

author: Logan
author_rank: Frequent Contributor
timestamp: October 18, 2021, 04:21:40 pm
content: Are there any IPS replacement panel for this connector/protocol?
Need help identifying 3000VA UPS and find manual - Page 1
Forum section: electronics / projects

author: Bendba
author_rank: Regular Contributor
timestamp: May 29, 2017, 11:23:54 pm
content: Hi,I scored a 3000VA UPS at the scrap yards yesterday. I thought for $20, just the case, fans and salvageable parts would be worth it.I couldn't resist the temptation to plug it in before tearing it apart. And surprise, it works. The batteries are dead but it works. I let it charge overnight, tested it with a 500W load, it ran for 10 minutes before the batteries gave upSo I might just keep it and get some new batteries. That'd be handy with all the blackouts we get at home.Or even use it as an inverter when I travel?I'd like to identify it and find the user's manual for it (most particularly the details for the remote port at the back)But when I search the model number online, I get nowhere.Does anyone know what the brand could be?Thanks in advance

author: najrao
author_rank: Regular Contributor
timestamp: March 25, 2020, 12:24:20 pm
content: I know this is a very old thread, and that none replied then.I haveexactlythe same UPS, and it says Siemens on it. I was told S sold the UPS business to Chloride (batteries), but I do not know any more. Mine works too, have run through three sets of batteries.Has anybody got any sort of manual or even specs?

author: amyk
author_rank: Super Contributor
timestamp: March 25, 2020, 01:43:13 pm
content: According to this page:http://www.nestor.minsk.by/kg/1997/22/kg72212.htmIt could be a Powercom ONH-3000.
Need help identifying a fan header? - Page 1
Forum section: electronics / projects

author: petreza
author_rank: Contributor
timestamp: October 12, 2015, 09:36:34 am
content: Hello,I would like change the fans of a Poweredge R810 with quieter ones. The problem is that the current fans use what appears to be a proprietary header. I want to preserve these fans so I do not want to cut and splice the headers from them to the new fans. I checked on DigiKey with no luck.Here are some pictures:In case the exact thing cannot be bought off the shelf, I would be happy with a header that matches the "plug" portion; I do not strictly need the flat "base" portion.Here are the dimensions of the "plug" part:5.8mm X 7.2mm2.5mm - distance between the pins10mm - the "height" of the "plug"Thanks again for your help!

author: amyk
author_rank: Super Contributor
timestamp: October 12, 2015, 02:56:47 pm
content: Is it 2.5 or 2.54mm (0.1")? Because the latter is very common.http://www.digikey.com/product-detail/en/M20-1070200/952-2030-ND/3727994These have the polarising key, but might not fit depending on what the key on your socket is like:http://www.digikey.com/product-detail/en/22-55-2042/WM6442-ND/313627http://www.digikey.com/product-detail/en/65846-014ELF/65846-014ELF-ND/4272733

author: kolbep
author_rank: Frequent Contributor
timestamp: October 12, 2015, 03:03:41 pm
content: Just use dupont jumpers (the ones with a single female socket on them)Just plug 4 of them into the respective holes.Put them in the socket, a dab of silicon to hold them together,and Fanny's your Aunt

author: petreza
author_rank: Contributor
timestamp: October 17, 2015, 01:30:50 am
content: Thanks for the replies!Yes, must be the 2.54mm (.1inch) pitch. Thanks!I have the wires and the tips and the housings and the tools on order now.
Need help identifying a part - diode of some type - Page 1
Forum section: electronics / projects

author: toli
author_rank: Frequent Contributor
timestamp: March 23, 2013, 08:28:46 am
content: Hello Guys,I'm trying to find a replacement for this part:Its just marked with "76C". I know this is a diode (it actually seems like its a multi-junction diode - probably 3 diodes in series), but I don't have the part at hand to measure its forward voltage drop to know how many diodes are in there with 100% certainty.I was unable to find any info/datasheet for this part - any chance someone can shade some light on this part?BTW, it is used in an old Sansui amplifier for biasing of the output stage so that's why I know it actually a multi-junction diode.

author: SeanB
author_rank: Super Contributor
timestamp: March 23, 2013, 09:04:09 am
content: Output stage will have as many diodes as there are junctions. For a darlington output stage that would be 4 junctions. There will be a low value resistor in series as well to set the bias current across the emitter resistors as well. If quasi complimentary ( NPN power devices all round ) it will have 3 diodes.Replace with 3 1N400x in series, attached to the heatsink with some epoxy for thermal contact.

author: toli
author_rank: Frequent Contributor
timestamp: March 23, 2013, 09:27:56 am
content: Hello Sean,Thank you, I'm aware of what you said and did plan to use this method as well. However, I would like to find whatever data I can about this part anyway, since I didn't come across is in the past.

author: digsys
author_rank: Unknown
timestamp: March 23, 2013, 09:43:30 am
content: This is a long shot, but 76C looks like the marking of a TVS (Zener) 76V AC (Bi-directional).And it looks like ones I've used in the past, but that's just a quick GUESS !Edit: What are the rail Voltages?

author: toli
author_rank: Frequent Contributor
timestamp: March 23, 2013, 09:51:51 am
content: These can't be zeners with 76V, the supply rails are high enough, but they are used to bias the output stage of the amplifier (BJT's), so 76V will fry these transistors in no time
Need help identifying a transistor - Page 1
Forum section: electronics / projects

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 26, 2013, 05:31:35 pm
content: Hi!In the fight to fix my Artesyn XL130 power supply I need some help identifying some kind of transistor. It has the following writing:A431756-D94321I guess the last row is just a production date but so far I couldn't find much with the other numbers.Does anyone know what type of transistor this is? And maybe some alternative part I which is easier to source and which I could use instead?

author: fmaimon
author_rank: Unknown
timestamp: January 26, 2013, 05:42:33 pm
content: It's a TL431 or similar shunt voltage reference.

author: mark-r
author_rank: Contributor
timestamp: January 26, 2013, 10:20:03 pm
content: Unlikely to be a 2SA431 I'd have thought. That's a germanium RF transistor unlikely to turn up in a power supply. It's also been obsolete since the 70s and was in a 4 lead TO72 metal case.

author: bitwelder
author_rank: Super Contributor
timestamp: January 26, 2013, 11:15:18 pm
content: The logo on top of the A431 is that one from Astec. A quick search for Astec A431 brings e.g. to this datasheet:http://images.ihscontent.net/vipimages/VipMasterIC/IC/ASTC/ASTCD005/ASTCD005-1.pdf(three-terminal precision adjustable shunt reference)

author: Wuerstchenhund
author_rank: Super Contributor
timestamp: January 27, 2013, 12:30:24 am
content: TL431 looks good, and they are easy to get.Many thanks for the help!
Need help identifying an IC - Page 1
Forum section: electronics / projects

author: smbaker
author_rank: Regular Contributor
timestamp: November 11, 2017, 05:11:35 pm
content: I'm trying to reverse engineer an analog-to-toslink adapter, because the audio level on the optical output seems too low compared to the audio level on the analog input. I've identified a CS8406 audio transmitter which I believe is taking I2S and converting it to the optical (and coax) output. Now I'm trying to identify the IC that converts the analog input to I2S. There is an IC marked "543C 1426" that is connected to the audio inputs. It is a 10-pin surface mount package. However, I'm not getting any obvious correct hits during my googling. Anyone have an idea what this IC could be?Thanks,Scott

author: jaycee
author_rank: Regular Contributor
timestamp: November 11, 2017, 06:17:32 pm
content: CS5343

author: PA0PBZ
author_rank: Super Contributor
timestamp: November 11, 2017, 06:19:10 pm
content: https://d3uzseaevmutz1.cloudfront.net/pubs/proDatasheet/CS5343-44_F5.pdfEasy after googling 543C I2S(Edit: but still too late...)

author: smbaker
author_rank: Regular Contributor
timestamp: November 11, 2017, 06:24:22 pm
content: Yep, that looks like the one. Thanks!It looks like the converter does have the correct analog input network. Maybe my source device isn't driving the analog signal to the range I though it was...Scott

author: jaycee
author_rank: Regular Contributor
timestamp: November 11, 2017, 08:13:30 pm
content: Or it doesnt like driving a 10K input impedance. Try sticking a simple opamp buffer in front of it.
Need help identifying an IC - Page 1
Forum section: electronics / projects

author: censustaker
author_rank: Newbie
timestamp: October 22, 2015, 11:44:48 pm
content: I'm trying to work out how a cctv camera I have works and i'm having a hard time identifying an IC on the board, it's marked as follows:"V1733 02148 "It's a surface mount dual inline package (I'm sure of the exact size) 8 pins.

author: isopropilick
author_rank: Contributor
timestamp: October 22, 2015, 11:55:04 pm
content: can you take a photo?

author: censustaker
author_rank: Newbie
timestamp: October 23, 2015, 12:01:35 am
content: I attached an image.. the best I could get from my iPhone im afraid!
Need help identifying appropriate connector for FPC (BlackBerry trackpad) - Page 1
Forum section: electronics / projects

author: v01d
author_rank: Newbie
timestamp: August 25, 2019, 07:41:03 pm
content: Hi,I want to design a PCB which will interface to a BlackBerry trackpad sensor. Particularly, I'm using a BlackBerry 9800 sensor. I also have a BB 9900 sensor which I think has the same pinout but different pitch. There are previous sensors which use other kind of connector but I would like to interface with the 9800 at least for now. I need the appropriate SMT connector for my PCB but I don't know how to find the relevant part. Moreover, I don't know if it is a custom-made BB connector (do smartphone manufacturers do this?) or if it should be some standard connector. Ideally, I want to buy it from a reputable source such as digikey.The trackpads look like this:Close up pictures of 9800 (left) and 9900 (right) are here:Last one has a caliper in the picture (each tick, 1mm) so I'm guessing it is about 0.4mm pitch (13 contacts).This is what the connector looks like:Alternatively, I could try to design a PCB footprint so that I could directly solder the flex PCB to my PCB, however I'm not sure if it would be feasible. Maybe I can presolder the tabs over the holes and my PCB's footprint and then melt them together?Thank you!!
Need help identifying connectors! - Page 1
Forum section: electronics / projects

author: bhorst519
author_rank: Newbie
timestamp: October 14, 2019, 01:13:29 pm
content: Hi everyone, been reading this blog for a while, but this is my first post. I have a board that I'm looking to build a stand-in for. I have traced the terminals and reverse-engineered the functionality that I need, but I'm having trouble identifying a couple connectors.The first are female terminals used as a high-voltage (400 VDC), medium current (15 A) mezzanine connectors to pass power and relay-control signals to another board. These have the reference designators LF1 - LF14.The second are female pass-through terminals used as HVIL (high-voltage interlock) for a fuse cover. These have the reference designators LF15 - LF18.If anyone has any ideas of a model number for either of these, I'd very much appreciate it!