hybridfree/eevblog-posts huggingface dataset:
Help me choose between these power supplies pls - Page 1
Forum section: electronics / beginners

author: DaMaDo
author_rank: Contributor
timestamp: December 03, 2011, 09:37:19 pm
content: I'm just starting out and trying to learn all about electronics that I can right now. I'm currently reading 'Make: Electronics' by Charles Platt.I've got an arduino kit and some shields to build etc and will keep expanding as I learn.I'm currently in the market for a power supply. I'd rather get a decent one now than pay $20 for an adjustable AC adapter plus a better one later.The ones I'm looking at are the following:Tenma 72-8345Atten PPS3005SAtten APS3005SOn the Tenma, I like that it's very narrow so I it can fit on my desk better and can also be transported easier.I read some posts here about the Atten ones but they seem hit or miss.I'd like something that I won't need to upgrade for a long time, but I don't want to spend more than $150 now.Please help me decide.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 04, 2011, 06:00:47 am
content: I would choose the last one (i have it) because its simple linear old school deign which you can easily repair if something goes wrong. I blew once a quite expensive smps based power supply and here was no chance to repair it except getting a new board from manufacturer.

author: ciccio
author_rank: Frequent Contributor
timestamp: December 04, 2011, 10:16:23 am
content: Quote from: hacklordsniper on December 04, 2011, 06:00:47 amI second this opinion: I have a defective switch mode PS on my bench, smelling "cooked copper", and it's full of unobtainable parts.Regards

author: Psi
author_rank: Super Contributor
timestamp: December 04, 2011, 11:08:47 am
content: Get one that has a separate knob for voltage and current.It's quite annoying when you have to keep pressing a button to swap what the control does.

author: BravoV
author_rank: Super Contributor
timestamp: December 04, 2011, 06:19:42 pm
content: Quote from: Psi on December 04, 2011, 11:08:47 amAlthough at other type of power supply, just want to warn the problem of these kind ps that uses single knob that does everything, a friend toasted his expensive prototype board by accidentally turned the knob at "coarse" current mode while he thought it was at voltage "fine" mode, go figure.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 04, 2011, 06:22:22 pm
content: Quote from: Psi on December 04, 2011, 11:08:47 amIts invidual, i preffer programable supplies with keypad

author: DaMaDo
author_rank: Contributor
timestamp: December 04, 2011, 09:00:12 pm
content: Thanks all, I'll be looking more into the APS then. Luckily it's the cheapest of the groupEven with coupon, the Tenma is still $119.Hopefully I'll have the APS by the end of month.

author: hacklordsniper
author_rank: Frequent Contributor
timestamp: December 05, 2011, 05:58:43 am
content: Great, let us know which version you will recieve ( with thermal fan control or without)
Help me choose the right components! :) Boost converter, micro, etc. - Page 1
Forum section: electronics / beginners

author: cahe
author_rank: Newbie
timestamp: August 14, 2018, 04:56:16 pm
content: Hello,I'm thinking of creating my first more advanced (for me) project. It will be a boost converter for a 18650 battery (2.5V-4.2V) that will boost the voltage to 8v and when the time comes (when liion hits 2.75v) it will lover the boosted voltage to 7v (so a low battery alarm triggers on the device being powered). This solves one problem - the device is not designed to work with li-ion technology, and has higher low battery voltage alarm than ideal. Thus when using LiIon packs the alarm triggers much too early (noticable when charging that battery again. A 3000mAh battery only receives 1800mAh during charging)This boost converter should have the highest (reasonably speaking) efficiency possible, so this is worthwhile. Right now the low voltage alarm rings at about 7V (so for 2S LiIon pack 3.5V per cell). The device draws about 350mA at 8V. I can configure the packs in 1S2P or 2S1P configuration to gain some efficiency. I'm interested in SMT components. The boost converter should be ideally controlled by a PWM signal, since I'm planning on adding some kind of micro controller (maybe with a screen, buzzer, etc.). The micro could also control the transistion from 8V to 7V.Thanks in advance for all the suggestions and help!

author: cahe
author_rank: Newbie
timestamp: August 15, 2018, 12:48:12 pm
content: I'm thinking abouthttp://www.ti.com/product/TPS63070
Help me decide/decypher capacitor types for this schematic - Page 1
Forum section: electronics / beginners

author: JoeN
author_rank: Frequent Contributor
timestamp: August 17, 2016, 12:42:57 am
content: This is a circuit I would like to try to build. I have one problem with this thing, I can't tell what capacitor types Jim wants me to use based on his instructions. He says: 1) Do not use ceramic capacitors anywhere. 2) Use Mylar or Silver Mica. 3) 0.01uF=Polystyrene Preferred. These instructions just don't make sense to me because a bunch of the values are way too big for Mylar/Silver Mica and a bunch of the capacitors on the schematic are polarized, this seems to me he is indicating electrolytic, right after saying not to use them. I guess you have to. Here are the capacitors on the schematic, what kind do you think they should be?10000pF - Use polystyrene like Jim said? Are there more modern choices that would work? Could polypropylene be used instead? How about mica?5pF - mica?6800pF - mica?.1uF - since ceramic is out, I guess we must use aluminum electrolytic?.47uF - since ceramic is out, I guess we must use aluminum electrolytic?1uF - since ceramic is out, I guess we must use aluminum electrolytic?15uF - Aluminum electrolytic?10uF - Aluminum electrolytic?47uF - Aluminum electrolytic?100uF - Aluminum electrolytic?Schematic:http://cds.linear.com/docs/en/article/ubm_edn_20110811%2018Bit%20ADCs%20Ad%20Free.pdf

author: Len
author_rank: Frequent Contributor
timestamp: August 17, 2016, 06:56:39 pm
content: It doesn't specifically say not to use electrolytics, only ceramics are completely banned. I think it's obvious that the polarized caps (all fairly large values) are meant to be electrolytic.Mylar (PET) capacitors are easily available in the microfarad range, I don't see a problem with using those for the 0.1, 0.47, 1 uF values.

author: SeanB
author_rank: Super Contributor
timestamp: August 17, 2016, 07:31:56 pm
content: 5pF can definitely be a NPO ceramic, and for the 6n8, 10n, 100n, 470n and 1uF use either polyester or polypropylene, which will work here.

author: JoeN
author_rank: Frequent Contributor
timestamp: August 17, 2016, 10:54:02 pm
content: Thanks for both replies!
Help me decode AC IR protocol - Page 1
Forum section: electronics / beginners

author: pingo
author_rank: Newbie
timestamp: February 11, 2016, 10:11:50 am
content: HelloI have an air conditioner going by the brand name "Tosot". My remote control is broken so I borrowed another one and am trying to clone it.So far I have recorded some of the signals it sends. You can inspect the raw dumps. I made a program to transform the raw values into bits (above 1000 is a one and below 1000 is a zero). I am ignoring values above 2000: there are 3 and they never change - two values at the beginning and one in the middle - can anyone explain their purpose?.Also I noticed that all even bits are always zero and never change so I think only odd bits matter and the even ones can be stripped away.After removing the above-2000 values and all the even bits there are 63 bits left.I can see that the temperature is specified in the left part of the sequence in Little-endian as a number going from 0 to 14 (the temperature range is 16-30).Now I need some help or ideas on understanding the right side of the bits. Could that be a checksum? What are some approaches I could try to calculate it? I am thining maybe the sequence is composed of some Bytes + 4-bit checksum at the end? But the number of bits is 63 which is odd (in both senses). Any ideas or suggestions for the checksum algorithm?If you need more sequence dumps I can record more.Any help will be greatly appreciated.http://pastebin.com/QxsUsj9e- Raw dumpshttp://pastebin.com/raw/H8KV13gZ- Processed dumps, unstripped (above-2000 values are marked as -1)http://pastebin.com/dwPtfdB6- Processed dumps with above-2000 values and even bits removed (changes from one state to the other are marked with "^")
Help me design a DC/DC converter :) - Page 1
Forum section: electronics / beginners

author: syscall
author_rank: Newbie
timestamp: December 12, 2014, 03:20:18 pm
content: Hello,I am building a power supply. 0-30V 5A max. Initially i wanted to go for switchmode all around, but then i thought i only need a switchmode dc/dc 'buck' converter and a 150W linear transformer and 10A bridge to feed it. Control and feedback circuitry is going to be based on the atmega8. Do you know any resource with similar designs, so i could check my ideas with someone's project?I also have a few probably trivial questions:Suppose the transformer puts 30V 5Amax on the secondary, what maximum range of voltages i can pull from the output with buck topology?How do I calculate the inductance of the output stage (after the mosfet).Switching mosfets must switch always, right? i.e you cannot have 100% duty cycle PWM from controller?Thanks and have mercy on a beginners.edit: something like this: (see attachment)

author: Seekonk
author_rank: Super Contributor
timestamp: December 12, 2014, 04:04:33 pm
content: A bootstrap supply cap must go to common in order to recharge so it can't be 100%. However, my solar system is a bootstrap battery instead of a capacitor ( I have rechargeable batteries up the wazoo from local recycling). I use a UNO for my charge controller and use 12V secondaries from old UPS transformers as the inductor. At 490hz a little less than ideal but cheap. With a 255 PWM, that gives you about 200mv steps. Probably good enough for a bench supply.
Help me design selector circuit pls. - Page 1
Forum section: electronics / beginners

author: kimera
author_rank: Contributor
timestamp: January 18, 2025, 12:23:41 pm
content: Please help me design auto selector circuit from this conditionVccInput 9-80Vdc500mAMaxIF VccIn <=15Vdc to circuit AIF VccIn >=20Vdc to circuit B**lowcostThanks to everyone who commented

author: BennoG
author_rank: Frequent Contributor
timestamp: January 18, 2025, 01:33:40 pm
content: what is the current draw of circuit A and B ?

author: coromonadalix
author_rank: Super Contributor
timestamp: January 18, 2025, 01:41:49 pm
content: where here to help in any design, comment and improve if possiblebut not do the job for youno need for current draw sensing just some basic voltage comparators with set values for higher than, lower than ...you have tons of working principles on the weban examplehttps://forum.dronebotworkshop.com/help-wanted/easy-way-to-automatically-switch-circuits-on-and-off-when-a-certain-voltage-is-reached/even with cheap mcu like arduino you can define more controls like : settings - thresholds - conditions etc ...https://microcontrollerslab.com/automatic-power-source-selector-circuit-arduino/code not free tough

author: Ian.M
author_rank: Super Contributor
timestamp: January 18, 2025, 02:04:19 pm
content: Other considerations are how fast the input can rise/fall, and what delay is acceptable - i.e. expecting it to switch instantaneously from A to B or visa versa is unrealistic.Also the specification is ill-defined. What happens in the range 15 V < VccIn < 20 V?Should both A and B be off, or should it retain its previous state or something else?The near 10:1 supply voltage range (9 - 80 V dc) makes it difficult to get a regulated supply for the control circuit if more than a few mA is needed. Are any other (possibly stabilised) supply rails available?

author: kimera
author_rank: Contributor
timestamp: January 18, 2025, 03:09:34 pm
content: Quote from: coromonadalix on January 18, 2025, 01:41:49 pmThanks for the information, I will study more.

author: kimera
author_rank: Contributor
timestamp: January 18, 2025, 03:10:16 pm
content: Quote from: BennoG on January 18, 2025, 01:33:40 pm250mA max
Help me figure out what these T12 codes mean. - Page 1
Forum section: electronics / beginners

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 25, 2021, 06:28:53 pm
content: What's the difference between BC, BCF, CF and C ?What's the difference between D and DL ?I have a hard time understanding T12 tip codes...is there a guide or anything ?

author: Bassman59
author_rank: Super Contributor
timestamp: October 25, 2021, 06:39:37 pm
content: It looks like each tip size and shape has an ordering code. This is a surprise to you?

author: BrokenYugo
author_rank: Super Contributor
timestamp: October 25, 2021, 06:45:00 pm
content: https://www.hakko.com/english/products/hakko_fm2027_2028_tips.html#t12

author: Vovk_Z
author_rank: Super Contributor
timestamp: October 25, 2021, 08:31:29 pm
content: Quote from: l3gi0n on October 25, 2021, 06:28:53 pmI find only 3-4 types useful, so there is no need to investigate all of them.D24 is a universal tip. BC1 for small SMD (but possibly not for ultra-small). And there are several types convenient for large wires: D52/D4/D32/CF4/C4/BC3/BCF3.As for me, I use mostly only two tips: D24 and (sometimes) BC1.
Help me find a chip for my thermo sensor - Page 1
Forum section: electronics / beginners

author: THATguy
author_rank: Regular Contributor
timestamp: October 16, 2016, 01:25:36 pm
content: DS18B20 18B20 TO-92 Thermometer Temperature SensorData sheet link:http://cdn.sparkfun.com/datasheets/Sensors/Temp/DS18B20.pdfI need a chip that reads a certain current then switches off the circuit.Fairly simple operation. It will need to read the binary output of the thermostat.I've no idea of what sort of chip to look for, this will be a learning experience for me.So if you don't know, but have an idea of how/where to start that would also be great. Cheers in advance.

author: Towz
author_rank: Contributor
timestamp: October 16, 2016, 06:27:20 pm
content: Any microcontroller should do the job, but you need to program it to comunicate with the sensor via 1-wire bus. Seems a bit of an overkill to use such sensor though. If it's just a thermostat switch then a simpler sensor like the lm35 or tmp36 with a comparator (or a regular opamp) will do the trick.

author: THATguy
author_rank: Regular Contributor
timestamp: October 17, 2016, 06:40:22 am
content: That's awesome, thank you so much.

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: October 17, 2016, 08:06:37 am
content: Are you from Samsung?

author: THATguy
author_rank: Regular Contributor
timestamp: October 17, 2016, 09:01:02 am
content: LOL, I want to get a note 7 and walk around pretending to talk on it, and have a little vapouriser inside, so smoke is coming out the top.COPYRIGHT my joke COPYRIGHT
Help me find an alternate for C1765 transistor? - Page 1
Forum section: electronics / beginners

author: AtLarge
author_rank: Contributor
timestamp: May 24, 2019, 02:51:42 pm
content: I am striking out on this THT. I have no other information on it. :-(

author: picburner
author_rank: Frequent Contributor
timestamp: May 24, 2019, 03:03:56 pm
content: It is a Toshiba RF transistor: 2SC1765See attached data sheet.Someone sell it on ebayhttps://www.ebay.com/itm/2SC1765-Original-Toshiba-RF-Transistor-with-built-in-Heat-Sink-Tab-2-pcs/291335516701?epid=1437120765&hash=item43d4f3321d:g:l44AAOSw7ThUmwjw

author: mikerj
author_rank: Super Contributor
timestamp: May 24, 2019, 04:29:22 pm
content: Equivalent to NE224 and SK3049, they were sometimes used in the RF output stage of early CB radios. I doubt there is anything modern with the same package style however.

author: AtLarge
author_rank: Contributor
timestamp: May 24, 2019, 04:51:48 pm
content: Excellent. Thank you!
Help me find this 8pin touchpad connector - Page 1
Forum section: electronics / beginners

author: andrialca
author_rank: Newbie
timestamp: January 27, 2025, 07:39:18 pm
content: Hi everyone, this is my first post, and I need some help.I recently salvaged an Asus ZenBook 14UX425JAthat had liquid damage. A part of the board controlling the fans, speakers, a USB-A port, and the microSD reader burned out, but I’ve already found a replacement.20250126_213641.jpgThe bigger issue is the 8-pin touchpad connector on the motherboard, which is also burned. The damage is on the plastic part of the connector and the connector itself. The traces on the motherboard seem fine to the naked eye.Does anyone know where I could find a replacement for this connector? I’m attaching photos for reference. Thanks in advance!

author: ahsrabrifat
author_rank: Regular Contributor
timestamp: January 29, 2025, 05:41:43 pm
content: You can search at digikey.

author: andrialca
author_rank: Newbie
timestamp: January 29, 2025, 08:04:45 pm
content: i can't find any similar one, what specifically i should search for?

author: inse
author_rank: Super Contributor
timestamp: January 29, 2025, 08:12:09 pm
content: FFC connector, # of pins and pitch (probably 0,635mm, measure with caliper) and whether contacts are top or bottom.The board is also damaged, do you feel confident fixing it?

author: andrialca
author_rank: Newbie
timestamp: January 29, 2025, 08:13:09 pm
content: i would like to try at worst it doesn't work like it does now, right?

author: inse
author_rank: Super Contributor
timestamp: January 29, 2025, 08:16:11 pm
content: buona fortuna!If you are not used to this kind of soldering job, buy a couple more of them.You will need a flux pen and solder wick, hot air would be beneficial.No pencil type soldering tip, small chisel preferred.
Help me find this plug - Page 1
Forum section: electronics / beginners

author: daslolo
author_rank: Regular Contributor
timestamp: April 04, 2020, 10:26:39 am
content: This old telescope from 2000 has a GPS patch with a plug that looks like a u-fl, maybe a tad larger diameter (difference below 0.1mm) but the center hole that receives the pin is wider, maybe by 0.1 or 0.2 mm so the patch antenna doesn't fit a u-fl receptacle of the new gps module I want to attach.Is that plug MHF3? Is there an adapter to u-fl I can purchase?
Help Me Find This Type of SMPS/Hi-Freq Transformer Supplier/Model - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 25, 2019, 12:56:41 am
content: transformer selection part is always baffling, digikey cant provide with the spec i want or lack thereof. this is to step up 5Vdc input to ±12V to ±18V (bipolar Vdc) output. power rating is around 6-12W preferably small size such as 1x1x1cm unit, or probably more if science doesnt allow such small size. but i saw small unit such as this..but usually they are getting power from mains 110-220Vac input. i need 5V input. the topology is something like in attached picture (transformer in the black lined box). 3 pins input centre tapped. centre pin will be Vdc+ input and both transformer end inputs will be alternatingly switched to create Vac effect. and then on the output, 2 pins only producing 12-18Vac, and later to be bridge rectified to get ±Vdc output. 3 pins centre tapped output also acceptable. toroidal type suggestion is also welcomed, and higher power transformer of this kind too are welcomed. any hint on transformer selection method, supplier or model number? thanks.

author: gcewing
author_rank: Regular Contributor
timestamp: July 25, 2019, 01:10:54 am
content: Things like that tend to be custom-made for a particular purpose, so it might be hard to find one off the shelf. You may have more luck searching for a ready-made dc-to-dc converter module.

author: Mechatrommer
author_rank: Super Contributor
timestamp: July 25, 2019, 01:23:57 am
content: Quote from: gcewing on July 25, 2019, 01:10:54 ami have few dc-dc modules and ICs but i need isolation in this design, so needing a transformer. yes diy is the last resort in mind, i also already have few smps toroidal and H shape core stock, but winding coils takes time, esp if i want to make many of them, and i lack knowledge in making efficient transformer...

author: temperance
author_rank: Super Contributor
timestamp: July 26, 2019, 10:29:16 pm
content: That's not difficult if you go for a flyback converter with this transformer: 750314782https://katalog.we-online.com/en/ctm/MID-POELT/S/750314782?m=n&sq=750314782&sp=https%3A%2F%2Fwww.we-online.com%2Fweb%2Fen%2Felectronic_components%2Fsearchpage_PBS.php%3Fsearch%3D750314782#vs_ct:2-This transformer has a 1:1 winding ratio between (5-3):(6-10):(7:9) which fit's your application.-Switching frequency: the inductance between (3-5) is 37µH. The energy stored in one switching cycle is 0.5 x L x I². The total energy transferred is 0.5 x L x I² x F.Regards

author: floobydust
author_rank: Super Contributor
timestamp: July 26, 2019, 10:36:55 pm
content: Coilcrafthas several transformers, based on a chipset or app note.
help me find this wire-side connector - Page 1
Forum section: electronics / beginners

author: Boschi
author_rank: Regular Contributor
timestamp: August 19, 2020, 12:27:59 pm
content: for a project im buying some of these:https://lcsc.com/product-detail/AC-DC-Power-Plugs-Receptacles_Ckmtw-Shenzhen-Cankemeng-DC-005-5-5-2-0MM_C132516.htmland because they are so cheap (and they are really handy) im buying some more than what i need.i was trying to also buy the wire-side connector, but it seems like im not having much luck in finding those. how are they called/what should i search?PS: while typing this im realising that i dont even know if my tecnical language about this is even correct. usually i call both the pcb side and the wire side connector, is it right? sorry for the silly question but im not mothertongue!

author: BILLPOD
author_rank: Frequent Contributor
timestamp: August 19, 2020, 02:05:05 pm
content: Hi Boschi, they are called 'Coaxial DC Power Connectors"Go here:https://www.cuidevices.com/blog/how-to-select-a-dc-power-connector

author: Vovk_Z
author_rank: Super Contributor
timestamp: August 19, 2020, 02:10:30 pm
content: Quote from: Boschi on August 19, 2020, 12:27:59 pmYou may try '5.5 2.0 mm connector plug'.

author: Benta
author_rank: Super Contributor
timestamp: August 19, 2020, 04:30:25 pm
content: Also called "barrel plugs".
Help me identify a Strain Amplifier - Page 1
Forum section: electronics / beginners

author: Atomillo
author_rank: Regular Contributor
timestamp: June 25, 2021, 01:30:26 pm
content: Hi:I recently became the owner of a rack with three 6M81 strain amplifiers and one 5636 control unit, all made by a brand called "San-ei" (I do not have the sensors)I tried searching the web for any data without any luck. I originally bought them cheap to use the rack and house my own electronics in the bins, but would appreciate if anyone here could point me to the uses that this device could have had in it's previous lifeMany thanks, and sorry if this is not posted in the right forum.

author: ledtester
author_rank: Super Contributor
timestamp: June 25, 2021, 02:01:58 pm
content: On the 4th page of this PDF:http://actaorthopaedica.be/assets/846/8372646.pdfthere is a description of measurements taken with the "6M81, NEC San-Ei Instruments, Tokyo".In 2006, Nippon Avionics acquired NEC San-ei Instruments and in 2008 changed its name to NEC Avio Infrared Technologies Co., Ltd.https://www.avio.co.jp/english/company/history.htm

author: Atomillo
author_rank: Regular Contributor
timestamp: June 25, 2021, 02:19:18 pm
content: Wow thanks!So if I understand this correctly, the amp is designed to be operated with two sensors in a Wheatstone bridge. Since the signals coming from strain gauges are normally very small (micro/mili volts right?) I wonder if perhaps this amp could be used as null detectors with good sensitivity.
Help me identify chip from samsung galaxy s5 - Page 1
Forum section: electronics / beginners

author: NickyYTSRB
author_rank: Newbie
timestamp: September 15, 2018, 12:56:13 am
content: I have took galaxy s5 a part and replaced chip called "SKC TI" because screen was not working. Now I have on extra. How can I find datasheet on it. I searched the web but all I can find is "SKC TI" for buying. No documentation at all. I want to save this and use it in future project if I can get hand on datasheet. I think that it is backlight controller but im not sure.Hereis exmaple.

author: NickyYTSRB
author_rank: Newbie
timestamp: September 15, 2018, 01:13:53 am
content: Quote from: blueskull on September 15, 2018, 01:03:32 amThanks for fast answer!! Well then its just gonna collect dust. I feel sad for that little ic.

author: perieanuo
author_rank: Frequent Contributor
timestamp: September 15, 2018, 01:21:21 pm
content: Google "galaxy s5 power ic skc " you find your soare parts in 2 minutes.Regards,pierreEnvoyé de mon iPad en utilisant Tapatalk
Help me identify component - Page 1
Forum section: electronics / beginners

author: Wild Rat
author_rank: Newbie
timestamp: November 29, 2016, 12:55:45 pm
content: Please, help me identify what component is this:

author: amyk
author_rank: Super Contributor
timestamp: November 30, 2016, 03:38:59 am
content: PIC16LF1503T-I/MG

author: Wild Rat
author_rank: Newbie
timestamp: November 30, 2016, 06:09:14 am
content: Thank you very much. How did you find this? I try all ways of googling with no result.

author: amyk
author_rank: Super Contributor
timestamp: November 30, 2016, 11:03:19 am
content: Google: QFN16 "MGC"You really need the quotes because for some idiotic reason Google thinks you're looking for "MCG" instead, which might be why you didn't find anything...
Help me identify part - Page 1
Forum section: electronics / beginners

author: DarkZero
author_rank: Regular Contributor
timestamp: July 12, 2019, 08:33:44 am
content: When i search for this part number i get no meaningfull results guess its a old transistor but i need specs in order to replace it

author: capt bullshot
author_rank: Super Contributor
timestamp: July 12, 2019, 10:12:02 am
content: There's no BCxxx transistor starting with two digit number, so it might be a BC174 (but these don't have the -40 suffix, rather A/B/C), so it isn't the BC174, same with the BC274, then we have a BC373-40 (but no BC374), no BC474, no BC574, 674, 774, 874There's a BCX74-40 made by Siemens, I guess this one is right, since there's some kind of X top left. Normally transistors of this vintage are marked with the full type number, just a bit scrambledSo its data: NPN, 45V Uceo, 800mA, 625mW,-40 indicates beta in the ballpark of 400.BCX types are usually fast switching bipolar transistors.http://www.rsp-italy.it/Electronics/Databooks/Siemens/_contents/Siemens%20Transistors%201980-1981.pdf

author: DarkZero
author_rank: Regular Contributor
timestamp: July 12, 2019, 04:47:24 pm
content: Let me give u some more info my dentist friend that does my teeth for free has these modules that die yearly that drive a pump now the service guys plugs in a new one and charges him a small fortune so he gave me couple of non working ones and i found that on all 5 this transistor is shorted so the malfunction repeats. I want to try and repair it so i can say thx to my friend for fixing my teeth free of charge. Besides this electronic module looks super simple.

author: Rigolon
author_rank: Regular Contributor
timestamp: July 12, 2019, 06:06:11 pm
content: I believe capt bullshot is right, since that symbol on the right side of the X mark was used by Siemens back then.I would try getting some equivalent transistors and using them to see if it's a match.
Help me identify the opposing connector - Page 1
Forum section: electronics / beginners

author: BollWeevil
author_rank: Newbie
timestamp: November 10, 2020, 06:38:57 pm
content: Can anybody help me figure out what kind of connector mates to this and maybe where to buy it? Trying to save $80 and three days on the Volvo part.https://photos.app.goo.gl/eZEWf2SUgXXP92A57

author: Gregg
author_rank: Super Contributor
timestamp: November 10, 2020, 08:41:34 pm
content: The mating connector is likely a standard automotive weather resistant one similar tohttps://www.ebay.com/itm/Amphenol-AT-Connector-Set-2-Conductor-18-16-Ga-Deutsch-DT-Compatible/382176534292?hash=item58fb7f1f14:g:ul8AAOSwMtxXrRTSThe same seller has lots of different ones available and the brands/types may lead you to other sources.You really need to measure the existing unit connector to ensure a proper connector.

author: BollWeevil
author_rank: Newbie
timestamp: November 11, 2020, 03:08:08 pm
content: I updated the pictures so you can see the measurements and the keying better. it's for a battery monitor sensor (BMS) from a 2nd generation Volvo S60 T5. it looks like the dimensions are about 1.1mm x 0.7mm Inside Diameter with an outside barrel length of 1.6mm, and I just measured the depth of the connector's opening (no picture) by bottoming out a small allen wrench, and it actually came to 1.8mm, so it appears it goes slightly deeper into the sensor than the exposed connector housing would indicate.doesn't seem to match that one on the ebay page.
Help Me identify This Battery Management Component - Page 1
Forum section: electronics / beginners

author: Mechatrommer
author_rank: Super Contributor
timestamp: October 08, 2017, 07:52:08 pm
content: Help Me identify This Battery Management Component... boxed in yellow. 3 big conductors, sort of carbon paste in the middle. maybe its a sensored fuse? or current sense? underneath of this thing is dipped in some form of solidified oily thing some form of coolant? not the white color. the white color is glue, there is another oilish thing underneath dark greenish color not seen in the photo. saw it in a picture of a laptop battery dismantled somewhere in the net cant find the description. anyone familiar?

author: amyk
author_rank: Super Contributor
timestamp: October 08, 2017, 08:44:06 pm
content: 3-wire triggerable fuse.
Help me identify this component?  Thanks - Page 1
Forum section: electronics / beginners

author: Rick Law
author_rank: Super Contributor
timestamp: March 19, 2013, 10:29:52 pm
content: This component is a unknown to me. With the attached picture, what are the two big black blocks with 101 labeled on them?That picture is not the picture of my actual component but look exactly like mine - mine is not in a position to take good pictures.Mine has 330 printed on where this similar component has 101 printed. Are they inductors? transformers? alien eggs?ThanksRick

author: 4to20Milliamps
author_rank: Regular Contributor
timestamp: March 19, 2013, 10:54:34 pm
content: alien eggs for sure.http://www.okokchina.com/p/ZZ-Other-Parts-Components/Chip-Inductor-SMD-Power-Inductor-424321.html

author: Rick Law
author_rank: Super Contributor
timestamp: March 20, 2013, 12:19:10 am
content: Quote from: 4to20Milliamps on March 19, 2013, 10:54:34 pmThanks! That was what I thought, but I was not sure. When I last looked closely at components closely, SMD was yet unknown and fastest Intel CPU's was the 8086...Thank-you again.Rick

author: 4to20Milliamps
author_rank: Regular Contributor
timestamp: March 20, 2013, 03:05:48 am
content: you are certainly welcome, and I know how you feel about the technology/age gap, I still use windows 3.1< the only operating system ever made that was worth a crap.

author: hammil
author_rank: Regular Contributor
timestamp: March 20, 2013, 11:54:29 am
content: Ah, the LM2596 module.. Wonderful devices, and cheap as chips too!
help me identify this PSU board... - Page 1
Forum section: electronics / beginners

author: Herschel
author_rank: Regular Contributor
timestamp: February 22, 2024, 05:51:36 pm
content: can someone plz help me to find from what this powersupply board actually came from. I got this powersupply board inside from a rip-off replacement powersupply of my water filter. so what is the actual specs of this powersupply board. I dont have much info about this board. its a 24v powersupply. I am not sure if they modified it to produce 24v. the powersupply dont like to run for a long time as the mosfet explodes every time under stress... i had a long time searching it on google lens, still no info...

author: coromonadalix
author_rank: Super Contributor
timestamp: February 22, 2024, 08:06:01 pm
content: trash this psu and try at least an 3 amp 24v psuyou see only one big rectifier diode on the transformer output ... witch i doubt it would endure an continuous 3 ampwant to play safe say 5amp ... don't buy china crap, go with meanwell or serious brandi know it could be costly but eh ....and to do your tests the best would be to try an variable psu with volt and current meter, you could see the real values needed ....

author: Jwillis
author_rank: Super Contributor
timestamp: February 22, 2024, 08:49:18 pm
content: PSU boards like the are as numerous and various as the products they're put into. Tracking down a published schematic is virtually impossible even if a brand name is available.This is what is called "proprietary" or exclusive right of the manufacturer that produces the product it's used for.Difficult to say if it's been modified unless you look at the solder joints. Specifically around the feedback opto-coupler PC1. But just at a glance the unit looks to be at best 2-3 amp.

author: MathWizard
author_rank: Super Contributor
timestamp: February 22, 2024, 11:15:27 pm
content: It's low part count for sure. Anything on the bottom side ? What does the load need ?

author: Herschel
author_rank: Regular Contributor
timestamp: February 23, 2024, 12:52:31 am
content: Quote from: coromonadalix on February 22, 2024, 08:06:01 pmthe "only one big rectifier" was put up by me. originally it had a smaller rectifier which gets really hot, desolders and shorts itself on operation. anyway i rewound the coil with a much thinner copper and it seems to handle that. usually chinese ones come with aluminum coil
Help me in finding error in maxwell theorem - Page 1
Forum section: electronics / beginners

author: A2
author_rank: Contributor
timestamp: July 15, 2014, 03:51:38 pm
content: I have attached a circuit.I have to measure voltage across load. I have used maxwell method to solve this.Problem is voltage across load comes out to be negative since current I2 that I have calculated comes out to be negative.However while simulation in multisim result is positive voltage.However magnitude is same in both case but I get error in sign.I don't know where I am doing error?

author: macboy
author_rank: Super Contributor
timestamp: July 15, 2014, 05:46:53 pm
content: Look at the 2k resistor. Look at the direction of the current flow in the loops that you have drawn. Look at the sign of the voltage that you have drawn on each side of the resistor for each loop. Is it all correct without any reversal between loop 1 and loop 2?

author: adi101
author_rank: Contributor
timestamp: July 15, 2014, 08:16:30 pm
content: i2 < i1, so the second loop equation is wrong.It should be 2000 (i1-i2).
Help me read this datasheet  - Page 1
Forum section: electronics / beginners

author: Hextejas
author_rank: Frequent Contributor
timestamp: January 25, 2018, 04:14:38 pm
content: I have a simple circuit where I want to turn on and off a led, plus dim it by controlling the gate on this jfet with a potentiometerWhat is the cutoff voltage that I need to apply to the gate ? Is it -6VThanks

author: frog_jr
author_rank: Newbie
timestamp: January 25, 2018, 04:44:46 pm
content: -6V to assure cutoff, but it "may" cutoff at as low as -1V
Help me replace this SMT LED! - Page 1
Forum section: electronics / beginners

author: K3mHtH
author_rank: Regular Contributor
timestamp: August 06, 2016, 08:54:43 pm
content: Hey everyone,I need to replace this surface mount LED, but I'm having a hard time finding an equivalent on digikey. It shines at a right-angle (you can see the lens sticking out the right side in the picture), and it measures .12" at the widest point (top to bottom in pic), and .04" wide (left to right in picture) without lens and .09" including lens. It is about .03" off the PCB.

author: Zero999
author_rank: Super Contributor
timestamp: August 06, 2016, 08:58:25 pm
content: What colour is it?Are you certain the LED is faulty?

author: K3mHtH
author_rank: Regular Contributor
timestamp: August 06, 2016, 09:03:35 pm
content: Quote from: Hero999 on August 06, 2016, 08:58:25 pmHey Hero, it is currently RED and working but not very bright at all (it is used to edge-light a piece of plastic behind an LCD display) and I'd like to replace it with a brighter version. For colour, I'd be fine with RED or WHITE. My problem is that I'm not sure if this LED is considered 1204 in size, and if this is what digikey considers "Surface Mount, Right Angle" as the mounting type.I'm not sure why this LED has gotten dimmer over the years, but from reading online it seems to be a common problem with this piece of equipment and everyone has had success replacing the LED's.

author: pyroesp
author_rank: Regular Contributor
timestamp: August 06, 2016, 10:28:23 pm
content: Why not change the series resistor that limits the current through the LED ?EDIT: Maybe R2 ?

author: GBowes
author_rank: Contributor
timestamp: August 06, 2016, 11:54:33 pm
content: Not easy to be sure of the size in your picture. If you measure the length and width you will know the package size. Yes, it is a right angle LED.A 1204 package would be 0.120" by 0.040"Graham

author: Lee Leduc
author_rank: Regular Contributor
timestamp: August 07, 2016, 09:33:25 am
content: Mouser stocks Kingbright brand Right angle SMT LED's. Maybe you can find something similar here.http://www.mouser.com/Optoelectronics/LED-Emitters/_/N-ec209?P=1z0z7pt&Keyword=kingbright+right+angle&FS=True

author: K3mHtH
author_rank: Regular Contributor
timestamp: August 12, 2016, 11:26:30 pm
content: Okay, replaced these LED's with some 1204 right-angle LED's.Even though I measured, the 1204 replacements were a lot smaller than the originals.. not sure what that's about. But they did span the pads fine, and they worked.So, I guess this thing had some LED's that went bad (very dim). Never seen that before!!
Help me route HS-USB on Dual Layer Board - Page 1
Forum section: electronics / beginners

author: luisr
author_rank: Contributor
timestamp: February 08, 2014, 12:49:01 am
content: Hi guysI'm designing a Breakout Board for a LPC1837JBD144 for personal use and development.After reading some HS-USB signal integrity articles I found one very interesting that fits just my designhttp://www.focusembedded.com/blog/high-speed-usb-in-a-two-layer-pcb/That article recommends to options when using fiberglass as core (0.062? thickness):1.- Use 18mil traces with a separation of 6mil from each other2.- Use “Co-Planar Waveguide” (CPWG) routing technique with 12mil traces and put GND between D+ and D-Now, I did some routing test and with 6mil clearance I can route using 18mil traces necking down to 15mil when approaching to the microcontroller pins, so... I can probably get away doing this. The second suggestions is not an option for me because I must route the trace through the corner of the microcontroller (between pins 36 and 37) and go under it in order to avoid using vias.I was trying to validate those values using Saturn PCB Design calculator and it gave me and Invalid input error, I would need to use 18mil/8mil to get it to calculate Zdiff and even then it would be way out the required 90ohms (Zdiff=127.216 Ohms Zo=110.446 Ohms)Do I really need to go with 4 layer pcb and use buried striplines in order to use high speed usb? I know I would no be able to achieve 480Mbits/s but I want to get my design as fast as possible!Thanks in advanceP.S I'm using eagle's length-freq-ri.ulp script and the difference in length between D- and D+ is about 1.01mm! that makes me wonder what would be the max difference in length before signal integrity becomes an issue (clock data skew is the term?) for this kind of signal (480Mhz)
Help me test this function generator - Page 1
Forum section: electronics / beginners

author: openthomas
author_rank: Contributor
timestamp: July 28, 2013, 06:33:44 am
content: Picked up a smartarb 625A. Trying to figure out if it is working OK, got it cheap. I hooked it up to my oscilloscope played around a bit ( see video at 2:04 ). I noticed that the frequency of the wave jumps around a bit. Is that normal ?How should I go about testing this thing ?

author: MasterOfNone
author_rank: Regular Contributor
timestamp: July 28, 2013, 10:22:17 am
content: What you are seeing might be normal, the frequency counter feature on your scope isn’t going to be as accurate as a dedicated Frequency counter.If you think the Frequency is really jumping around then don’t look at the trigger position on the scope. What you should do is adjust the Horizon position so that you are looking at the waves a lot later than the trigger position (I.e. the trigger position disappears off to the left of the screen). Then set the display to Infinite Persist. With your scope setup like this any frequency changes between the trigger position and the position displayed on the scope will cause the waveform to be drawn in a different position on the screen, and since the scope is set to infinite persistence you will see it. So you can leave the system running like this for a while and if the frequency is really jumping you should catch it.Remember you can test the principle by manually changing the Frequency of your function generator by a small amount temporally.

author: openthomas
author_rank: Contributor
timestamp: July 28, 2013, 09:39:52 pm
content: Ok I think I got that, take a look

author: MasterOfNone
author_rank: Regular Contributor
timestamp: July 29, 2013, 08:31:45 pm
content: That only looks like a bit of jitter to me. If the frequency was jumping temperately I would expect to see the wave drawn in a completely different place on the scope. However when doing the test I see that you have only move the horizontal position along 56.56us. If you moved the horizontal position further along you would have more of a chance of catching the problem on the scope, because every time the scope triggers there would be less of the capture to the right of the point you are viewing.But anyway the Frequency displayed on my DS1052E does the same thing as yours, but when I use my dedicated Frequency Counter I don’t see this issue.
Help me to understand air valve - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: June 30, 2025, 07:40:02 pm
content: Here are pictures of valve attached, what i understand it has two input points A & B, I do not understand its default settings, air coming into volve throught point B will out at point S.Point P is connected with A but this point is totally closed that means P is not useable.Point R is also not useable its not connected with anything.When i use it if i blow air through point B it passes out at point S, point P is totally block.its interesting that no matter Relay is on/off point P is blocked no air in or out, point B -> S is is always open for air in/outI wanted to learn how actually these kind of air volve are used.

author: Andy Watson
author_rank: Super Contributor
timestamp: June 30, 2025, 08:38:28 pm
content: Seems like an Airtac/clone of a 4V110-06. See part-way down this page for a description of its function:https://www.discountairvalves.com/4V110-06

author: BeBuLamar
author_rank: Super Contributor
timestamp: July 01, 2025, 09:26:42 am
content: Supply pressure to port P. Air will normally come out to either port A or B. When you put 24V to the coil it switches. Port R and S are exhaust ports and not connect to anything. The pieces on those are mufflers to reduce noise when air is exhausted out.

author: WattsThat
author_rank: Frequent Contributor
timestamp: July 01, 2025, 11:43:55 am
content: The input port is P (pressure)Output ports are A and B (connected to actuator/cylinder/piston ports)Exhaust ports are R and S and as pointed out, have mufflers installed. Sometimes there is a screw in the muffler that is an adjustable orifice that allows for control of the rate of change of the exhaust port(s).Coil de-energized:P -> BA -> RCoil energized:P -> AB -> SThese connections are shown pictorially on the valve body with the small diagram and the four diagonal lines.
Help me to test Marantz SD-74 cassette player - Page 1
Forum section: electronics / beginners

author: sairfan1
author_rank: Frequent Contributor
timestamp: January 13, 2024, 04:20:29 pm
content: I have an old cassette player from 80s which is not working, its power ONs but no further response, after some inspection I belive there could be issue with LC6502B OR LM6402H I tried to find datasheet on the internet but could not find enough so that I can test it. (BTW I'm not experienced in reparing)Some pins of LC6502B are directly connected to VFD display (Fluorescent display) and some go to VFD Driver AN6870NVFD segment who are directly connected to LC6502B are OFF (not litting) same is the case with LM6402H some of its pins are connected to front pannel (via TC7800) for play/stop/forward etc. buttons, but no response on pressing buttons, related LEDs stay OFFI tried to find datasheet for LC6502B/LM6402H could not find something informative but looks thease are 4 bit microcontrollers, I was not able to find any information that can help to understand expected voltage/signal on its different pins,I'm looking for help, based on this information can I investigate LC6502B/LM6402H are the reall problem?EDITED: describe further and include pictures

author: wasedadoc
author_rank: Super Contributor
timestamp: January 13, 2024, 04:33:39 pm
content: Photo?

author: z2000
author_rank: Newbie
timestamp: January 15, 2024, 09:11:45 pm
content: I have the Marantz SD 74 service manual. I don’t know how to load it here or send it to you if you need it.

author: wasedadoc
author_rank: Super Contributor
timestamp: January 15, 2024, 09:55:56 pm
content: Complete mix of Japanese ICs. I suspect the LC6502 one is a Sharp device.Does the motor run when it should?