hybridfree/eevblog-posts huggingface dataset:
I have a torroid an ebay LCR and magnet wire. Balun for HF? - Page 1
Forum section: electronics / beginners

author: Beamin
author_rank: Super Contributor
timestamp: November 05, 2017, 09:33:30 pm
content: So I have lost my ebay 10$ HF balun that was just a tiny torroid and some magnet wire.Is it possible to make a balun/unun for RX with my SDR for below 30MHz? Its a 82' long wire that attaches to coax and ground at the bal/unThe torroid is3cm dia1 cm dia hole in the middle0.5 cm thick (side) X 1.cm thick (front to back) gray magnet like materialI have magnet wire and a ebay LCR meter like seen on eevblog.How important is the torroid size for making this work? The whole balun unun always screws me up when going from coax to a longwire that's open on one end. That's an unun right? Coax is 75 ohm rg6.
I have an LED DRIVER on several Aquarium lights...looking for info on the LED dr - Page 1
Forum section: electronics / beginners

author: OutThere
author_rank: Contributor
timestamp: September 19, 2024, 02:23:48 am
content: I tried search first. all i found was a chip with the same company logo that was a driver of some sort for a SMPS. I believe the company is iweek.cn. I went to their website clicked translate to english when i searched reverted back to Chines. the chip is an LED driver DP9511. Its's a submersible tube with an LED strip. I have repaired several ( replaced burnt out SMD LED) but they only last for a day then I checked the power output way high. I checked the power output of a new one and it was 3v x the number of smd led's. so was wondering if some could get me a data sheet or equivalent data sheet. Something else crossed my mind, well actually 21. whatever the count of LEDs they seem to have the same chip. only parts on the pcb are the afore mentioned chip, an electrolytic cap, and a small power resistor. do they use an RC network to select the output voltage?2. it's possible that the light strips were defective to begin with the higher voltage, like i said the new one was led count times 3vI think humidity/ condensation may build up and short out the unit......some this happens to others work fine so not sureI think i found what I was looking for if you want to still look to...great or comment on how the chip functions would like to hear that alsohttps://www.scribd.com/document/662331058/DP951X-REV1-0-CN

author: BennoG
author_rank: Frequent Contributor
timestamp: September 19, 2024, 05:22:56 am
content: Usually they do constant current output, so the number of leds does not matter.When measured with a unloaded output the voltage can be high 70V is no exception.You need to measure the output when the circuit is loaded and the leds are working.Benno

author: tunk
author_rank: Super Contributor
timestamp: September 19, 2024, 11:03:15 am
content: The resistor connected to the CS pin probably sets thecurrent - doubling the resistor value may half the current.Edit: Currently I'm playing around with an LED driverbased on an LC6640 chip. On that it seems that increasingthe resistor value, the max output voltage is reduced.It may also be the case for your chip.
I have bought a 998D Soldering Station Need Help - Page 1
Forum section: electronics / beginners

author: Canna
author_rank: Newbie
timestamp: August 20, 2018, 10:45:39 pm
content: Hi there boys and girls,This is my first post here and i have come for your advice..I bought the 998D soldering station from ebay.I wont be using this unit day in day out just the occasional job here and there..I received the item today and kinda shocked what i found inside..I was just wondering what use guys advice me to do or recommend.Or If someone here may of owned one of these and what they did..So My question is, Would i be ok to ground/earth the unit to the case from the crimp that is attached to the laminations on the transformer, I obviously should ground the case,But i wanted to hear from you all what should i do to make this unit safe to use thank youHere are some pics i have fixed the hot air earth alreadyhttps://imgur.com/a/9n3g4Wb

author: JS
author_rank: Frequent Contributor
timestamp: August 21, 2018, 04:29:49 am
content: Check for continuity but the case should be already grounded by the transformer mounting screw...JS

author: Ian.M
author_rank: Super Contributor
timestamp: August 21, 2018, 06:19:42 am
content: Not that that's acceptable. The main protective ground connection should never be via a mounting bolt or screw of any other part, as there is a risk of it being loosened by vibration or during maintenanceIt should be to a dedicated bolt, or welded on stud. If a bolt is used, it should have no washers under its head, and on the other side, a sharp star washer against the chassis with paint removed under it, then a spring washer and a nut. Grounds are then connected with crimped ring terminals on top of the first nut followed by another spring washer and a nut. The final nut should ideally be locked - either two thin nuts locked together, or with threadlocker or a locknut.

author: Canna
author_rank: Newbie
timestamp: August 22, 2018, 09:51:01 pm
content: Thats what i thought, i have made a solid earth to case now and with earth feed connected, the transformer posts do go through to the case and are screwed but they have coated everything so thick in paint it did not earth,, i have sanded to bear metal all point that should be earthed and left those that should not.. Thanks for your reply's i just wanted to make sure
I have question about battery pack? - Page 1
Forum section: electronics / beginners

author: rks96
author_rank: Contributor
timestamp: September 28, 2020, 02:55:39 pm
content: I have 10 lithium cells! Each cell have a stand alone protection board uses DW01A (2 stand alone 8205A mosfet version) with discharge current protection of around 3ahttps://www.best-microcontroller-projects.com/dw01a.html. I want to create a battery pack 5c2p using separate multi cell BMS boardhttps://www.aliexpress.com/item/32889959726.htmluses bm3451 BMS chip.5 cell BMS has discharging current: 25A and protection 60A (way too much for 2 of my cells in parallel)! If I use small single cell protection board on each separate cell my 5cell pack will be limited to around 2*3=6a max (2 cells in parallel) which is fine by me!In short, it would work like this: I think!Overcharge protection - > BIG 5 cell bms @ 4.23 - 4.28V! Single cell protection board would trigger only @4. 3V.Single Cell over-discharge protect voltage - > BIG 5 cell bms @2.72 - 2.88V! Single cell protection board would trigger only @2.4V.Over-discharge protect current -> protected by a single cell protection 3A a but I use 2s in parallel so 6A (if over current situation, then one of cell protection triggers first and then soon after other cell protection triggers since now all power has to come from only on cell). 5s BMS would trigger only @ 60A.Each single cell has 10000mah capacity (5s2p --> 20000mah @ 21v).Should I remove Single cell protection boards or leave them be? I am not planing on using more than 6a at any time anyways, but I still would like to have all protection and power possible! MYB each cell can handle more than 3a safely if I remove the single cell protection?PS1: I didn't add single cell protection boards! Cells came with them already added! Also, I will not use included thin wires!PS2: I will use CV-CC6A charging so these protection functions I don't care about!PS3: Everything is from China so I don't know if I can trust any of these values!Thanks in advance!

author: sleemanj
author_rank: Super Contributor
timestamp: September 28, 2020, 04:47:06 pm
content: Leave them in place so you have lower current limit. 60A limit is too high for 2p of normal cells.

author: MosherIV
author_rank: Super Contributor
timestamp: September 28, 2020, 05:20:48 pm
content: The single cell built on board protection circuit will limit the total current of the series chain to 3A.If I understood what you have said.You will not be able to acheive higher current unless you remove the single cell protectiin circuits.Make sure that cell voltages are within 0.01V when joining cells in parrallel or high balance current will flow when you join then together.It is also best to make sure cell voltages are balanced when joining in series or you will have (series) unbalanced pack
Intel C4004 Like IC, Need help Identifying it - Page 1
Forum section: electronics / beginners

author: CoopedUp
author_rank: Regular Contributor
timestamp: August 31, 2019, 04:40:59 pm
content: I don't know what this is, I have tried looking up the numbers but I feel like this is a custom batch or something for a company or I just suck at looking things up. I have previously owned a C4004 and this looks fairly similar just different numbers. Anyways If anyone knows what these are I would appreciate knowing as well thanks!

author: CoopedUp
author_rank: Regular Contributor
timestamp: August 31, 2019, 04:52:41 pm
content: What I mean by custom batch is like a Heathkit run or something.

author: Brumby
author_rank: Unknown
timestamp: September 01, 2019, 01:33:51 am
content: Don't get too focussed on the look. It's a 16 pin DIL ceramic package - which could house any one of a number of chips.The markings don't click with me - but then I'm no aficionado. There's a good chance someone here might have an idea.

author: amyk
author_rank: Super Contributor
timestamp: September 01, 2019, 02:19:57 am
content: 7181 looks like a datecode for 1971, which would mean Amelco/Teledyne 300 series "HNIL" (High Noise Immunity Logic, a DTL variant) looks about the right timeframe; 311 is an RST flip-flop and at least the number of pins on the package lines up. I've attached some more info on that family, and since it has a schematic of the 311 you can try to test the pins with a multimeter and see if that also matches.(Source is "Anglo-American Micro-electronics Data 1968-69", which is basically one huge databook; the whole thing can be found at the usual places online if you're curious.)

author: CoopedUp
author_rank: Regular Contributor
timestamp: September 01, 2019, 02:53:04 am
content: I also have some of these smaller round transistors like semiconductor if anyone knows what they are.
I have trouble finding male-to-male USB C OTG cable, am I doing something wrong? - Page 1
Forum section: electronics / beginners

author: dusan
author_rank: Regular Contributor
timestamp: July 27, 2025, 05:57:31 pm
content: I'm making device with STM32G030 and I use CH340 for usb to uart. I will use USB-C female connector on this device (https://www.lcsc.com/datasheet/lcsc_datasheet_2205251630_Korean-Hroparts-Elec-TYPE-C-31-M-12_C165948.pdf). Normally I use PC to communicate with the device by using "USB A male to male C" cable.But this time I need to be able to communicate with device using my android phone. I have "OTG Male MicroB to Female A" cable. I plug OTG microB to my phone and another cable which is "Male A to Male C" which goes to device. This works, I just tested it, on phone I see serial data and I can communicate with it and everything is fine. Btw that OTG is just 5th pin connected to ground in the male microB connector (on the phone side) to tell the phone it will now be host.But my new phone will have usb C connector. I wanted to get rid of extra cable and find "OTG usb male C to male C" cable but I have trouble finding one (e.g. on aliexpress). Does this mean I'm doing something wrong? Does OTG behavior changes somehow when switching from microB to C? Or can I use "non-otg male C to male C" cable? I still want to retain possibility of using PC to communicate with it. I can find non-otg male to male C cables, but not "OTG male C to male C" cable.

author: wraper
author_rank: Unknown
timestamp: July 27, 2025, 06:19:49 pm
content: There is no such thing as USB-C OTG cable. If it a special OTG cable, it means one of the connectors is not USB-C.

author: xvr
author_rank: Frequent Contributor
timestamp: July 27, 2025, 09:02:12 pm
content: USBC do not implement OTG. It use DRP (Dual Role Port) instead. It has almost the same functionality, but implemented in different way (USBC only way). DRP detect type of connected device on other end of USBC cable and switch itself accordingly. Plain USBC cable used, nothing special (as wraper aleady said)
I just bought an oscilloscope and was wondering if it is enough - Page 1
Forum section: electronics / beginners

author: TheGeneralLee86
author_rank: Newbie
timestamp: April 10, 2022, 12:05:06 pm
content: for working on Vintage computers up to Pentium 4 computers and the one I bought the Rigol Oscilloscope DS1202Z-E? I know I am pretty happy with it and will be my first time ever using an oscilloscope and getting a bit more in depth repair my vintage computers. I am pretty excited.

author: chinoy
author_rank: Regular Contributor
timestamp: April 10, 2022, 12:48:13 pm
content: It should do you fine.Congrats on your new scope.

author: TheGeneralLee86
author_rank: Newbie
timestamp: April 10, 2022, 01:04:17 pm
content: Quote from: chinoy on April 10, 2022, 12:48:13 pmOk Thank You I was not sure and was a little worried about it because I am obviously new to Oscilloscopes. I also just bought a couple Multimeters and a 2 in 1 Heat Gun and Soldering station 8786d I from Yihua and the AstroAI MUS10KRD 10k Counts and M6KOR 6k Counts Multimeters.
I love old equipment - Page 1
Forum section: electronics / beginners

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 08, 2013, 04:33:01 pm
content: Hello , I love old equipment which has made me buy this bench multimeter its a Heathkit MI2202, I'm sure some on here will know of the model, it's another piece of old equipment I'll clean up and get back into shape, does anyone know where I could get a manual .pdf, or does anyone know this model type , any info would be grately received.

author: kfitch42
author_rank: Frequent Contributor
timestamp: February 08, 2013, 07:39:14 pm
content: https://www.eevblog.com/forum/chat/some-jerk-is-squelching-heathkit-schematics/

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 09, 2013, 11:23:03 am
content: Not a bad reading from a 30 + year old meter, I've given it a quick clean, & it's running on batteries ,until I change the power socket

author: seb1982
author_rank: Regular Contributor
timestamp: February 11, 2013, 10:03:09 pm
content: Wow - can you feel the envy coming through my broadband connection?! That's a gorgeous thing!I can never seem to find nice, old Heathkits anywhere in the UK except from America on ebay with massive postal costs!God, I wish Heathkit were still going - they'd knock seven shades out of those crappy Maplin kits!

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 12, 2013, 05:08:29 pm
content: I got this one on E-Bay UK, just going to give it a modern power socket

author: ModemHead
author_rank: Frequent Contributor
timestamp: February 12, 2013, 06:29:55 pm
content: I owe a lot of my early interest (and education) in electronics to Heathkit and Radio Shack kits. You might enjoy thislook inside Heathkit Nixie-tube multimeterthat I have. I guess it pre-dates the LED version by a few years.

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 12, 2013, 06:43:23 pm
content: Oh I love the nixie tube gear, I keep looking for a nixie tube frequency counter on e-bay

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 12, 2013, 06:45:17 pm
content: Quote from: M0BSW on February 12, 2013, 06:43:23 pmNow even I'm envious, lovely equipment

author: M0BSW
author_rank: Frequent Contributor
timestamp: February 12, 2013, 07:19:02 pm
content: Now then fellow Radio amateur that is plain greedy, and I can't blame you for so having so many
I made a google docs file about RC circuits and hope you will review it :) - Page 1
Forum section: electronics / beginners

author: renzoms
author_rank: Regular Contributor
timestamp: November 01, 2019, 03:52:40 am
content: https://docs.google.com/document/d/127mfGEHilpGyUfLXKS0QMOAmICfD92BGcwr-xGTOVEY/edit?usp=sharingWhy: There are some things I am certain could be described better or may be misleading/almost correct or completely incorrect. Example: current leads voltage by 90, although an RC circuit with R = 2000 and C = .001 supplied a sinusoidal voltage will not exhibit this. Hoping you can mentor me here.I am not going to school; this isn't school related. I am going to analyze sawtooth and triangular waveform tomorrow. Thanks for anything positive, kind, and good. The notes highlighted in yellow are what I would appreciate a comment on, elaboration on, an example or you sharing personal experience related to the thing. The note highlighted in red is the example and an indication of this doesn't make sense to me anymore.

author: george.b
author_rank: Frequent Contributor
timestamp: November 01, 2019, 07:36:27 pm
content: Current leads voltage by 90 what, platypuses, bananas, degrees?Assuming you meant degrees: current will lead voltage by 90 degrees in a purely capacitive circuit. In an RC circuit with 2000 ohms and 0.001F (assuming you meant ohms and farads, and not stones and furlongs), that is not the case.How good are you with complex numbers? This is all much easier to understand in the complex domain, in terms of phasors and complex impedance.Given that a capacitor's impedance is 1/j(2*pi*f*C), a series RC circuit's impedance, Z, would equal R-j/(2*pi*f*C), with R being Resistance, f being Frequency, C being Capacitance, all units in SI, and j denoting the imaginary unit.You may then calculate current, I=V/Z, which will yield a complex number, with a magnitude and an angle (a phasor). With this, you can see why, in a purely capacitive circuit, current leads voltage by 90 degrees, and, conversely, why that phase angle isn't 90 degrees if there is a resistive component.

author: renzoms
author_rank: Regular Contributor
timestamp: November 02, 2019, 08:03:43 pm
content: Quote from: george.b on November 01, 2019, 07:36:27 pmThanks. I appreciate your comment George B.
I may have... unintentionally... made a transformer. - Page 1
Forum section: electronics / beginners

author: corrado33
author_rank: Frequent Contributor
timestamp: July 22, 2014, 11:39:06 pm
content: I work with high temperature fuel cells and recently I've been fabricating an oven to bring a newly built apparatus up to 750-800 C. I'm actually using two ovens, an outer oven and an inner oven. The outer oven heats the entire assembly up to 20-30*C below the required temp, and the inner oven brings it up to temp. The temperature of the cell is very slow to respond to changes in current for the outer oven, hence the use of the inner oven.Anyway, I've had a problem with inner ovens breaking recently (I'm in the development stage, it happens) and the other day, while the device was at 650C or so, the inner oven failed. (Actually, now that I think about it it may not have failed...). Anyway, I went to measure the resistance and I was getting -300 kOhms. Yes, you read that correctly, negative resistance.I didn't think anything of it until I read the "Stupid things you've heard people say" thread. I guess I created a transformer. Next time I heat it up I'll have to measure the voltage.Anyway, thought it was funny.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: July 23, 2014, 12:19:51 am
content: If you measured it while it was still hot, the meter might've been confused by thermal or chemically generated voltage. Just a few microamps would do.Tim

author: retrolefty
author_rank: Super Contributor
timestamp: July 23, 2014, 12:41:19 am
content: Quote from: T3sl4co1l on July 23, 2014, 12:19:51 amAh, acting like a giant thermocouple?Next time you measure resistance while hot try both polarity to see if it is a active voltage effecting the resistance reading. Then measure DC voltage to see if there is a small Seebeck effected voltage presence at high temp.
I need a basic serial WiFi module - Page 1
Forum section: electronics / beginners

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 30, 2022, 01:21:30 am
content: I have a couple projects that need WiFi connectivity, simple connectivity. I don't need Arduino compatibility, GPIOs, or any kind of programmability beyond basic setup. About all I'm finding are ESP8266-based modules that apparently need to have firmware flashed through the Arduino IDE or micro Python to function. I need a basic WiFi module that can be configured through AT commands and has serial input and output. These will be attached to PIC UART peripherals. Any suggestions?

author: Jwillis
author_rank: Super Contributor
timestamp: December 30, 2022, 06:07:50 am
content: Ublox NINA W13 serieshttps://content.u-blox.com/sites/default/files/NINA-W13_DataSheet_UBX-17006694.pdforDigi XBEE Wifihttps://www.digi.com/products/embedded-systems/digi-xbee/rf-modules/2-4-ghz-rf-modules/xbee-wi-fiBoth found at Digikey

author: Ian.M
author_rank: Super Contributor
timestamp: December 30, 2022, 08:11:12 am
content: Its worth noting that most reputable suppliers will ship ESP-01 modules with ESP8266 "AT" command firmware preloaded.

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 30, 2022, 12:25:39 pm
content: Quote from: Jwillis on December 30, 2022, 06:07:50 amThe Nina is a nice looking unit , but only available in a surface mount configuration that I can't work with, Also appears to be out of production.XBEE will work, but is pretty spendy at about $50/ea.Quote from: Ian.M on December 30, 2022, 08:11:12 amNoted, I'll revisit some options.

author: MLXXXp
author_rank: Frequent Contributor
timestamp: December 31, 2022, 03:17:10 am
content: You might be able to find something from Hi-Flying Technologyhttp://www.hi-flying.com/iot-moduleI have theirHF-LPT200module and found it could be configured once using AT commands in such way that it will then always automatically connect to a Wifi Access Point (AP) and open a TCP link. It will then go directly into a mode that transparently passes data, unaltered, between TCP and the serial port (called throughput mode, which the ESP8266 calls unvarnished mode).The HF-LP200 is quite old (2013), so I don't know if it's still available but it's likely that some of their newer modules can do the samehttp://www.hi-flying.com/embedded-wi-fi-module-series/low-power-tiny-smt-moduleEdit: I just noticed that you don't want surface mount. They also make modules with pin headers that may have the same functionalityhttp://www.hi-flying.com/embedded-wi-fi-module-series/low-power-moduleHere's a post detailing my use of the HF-LP200, which includes the AT commands I used.https://community.blynk.cc/t/mangocube-hf-lpxx00-usr-wifi232-how-to/5895As I posted, Jinan USR IOT Technology Limited may have equivalent or similar productshttps://www.pusr.com/products/wifi-modules.html

author: Ground_Loop
author_rank: Frequent Contributor
timestamp: December 31, 2022, 04:05:50 am
content: Thanks for the responses. Based on Ian's reply, I ordered a handful of ESP-based modules off Amazon. I'll see where they take me.
I need a bit of advice please - Page 1
Forum section: electronics / beginners

author: Unknown
author_rank: Unknown
timestamp: July 09, 2013, 07:55:51 pm
content: Hello, Firstly I need to build a wide range VFO, I have a feeling these are a bit of a black art, to get them right. Secondly I need to build a Noise source that quite rich in noise content, and do you shield these ?

author: PA0PBZ
author_rank: Super Contributor
timestamp: July 09, 2013, 08:02:20 pm
content: What is a wide range, and what is the range?Let's say you want 0-100Mhz, the normal way to do that is to mix 2 higher frequency sources to get what you want, so for instance a 500Mhz fixed source and a 500-600 Mhz VFO. You can't just make a VFO that goes from 0 -100Mhz...

author: Unknown
author_rank: Unknown
timestamp: July 09, 2013, 08:05:41 pm
content: Quote from: PA0PBZ on July 09, 2013, 08:02:20 pmThat would do nicely, I thought it was more complicatedThere are parts of our hobby I just don't understand.

author: vk6zgo
author_rank: Super Contributor
timestamp: July 11, 2013, 03:12:41 am
content: A 500-600 MHz VFO is no pushover,either!You're not going to make a stable free running one,you are looking at a PLL or similar for that sort of frequency.Oh,& its output should be within a dB or so over that range!Maybe you can crystal lock the 500MHz fixed oscillator,but you will probably have to either multiply it up from a lower frequency,or use another PLL.You are then stuck with designing a mixer & output stage which is flat from 0--100MHz!Complicated?----No,but incredibly difficult to actually do!This is why test equipment manufacturers charge big bucks!
I need a circuit diagram for a simple waveform monitor?? - Page 1
Forum section: electronics / beginners

author: Azhar
author_rank: Regular Contributor
timestamp: November 23, 2014, 06:38:22 am
content: I want to try to build a simple waveform monitor, something like an oscilloscopebut without all the fancy function, I just need the circuit to show the waveform by connecting it to a tv or LCD .. etcIs there anyone who built something similar? or maybe have a schematics?

author: rs20
author_rank: Super Contributor
timestamp: November 23, 2014, 06:53:00 am
content: Quote from: Azhar on November 23, 2014, 06:38:22 amWhat kind of frequencies are you interested in capturing? Do you want to be able to read off voltages, or are you happy with a completely uncalibrated display? Do you want to have a selection of different timebases, or are you happy with just having one fixed timebase?Driving a TV or LCD is much more challenging than capturing a low-frequency waveform, so that's probably going to be your main concern if you want to build a device that just displays whatever kind of waveform.I can imagine an interesting yet hacky approach which would be to drive a VGA monitor, and set up an internal sweep that sweeps along with the horizontal scan, and when the sweep matches the input voltage, it makes the current pixel white. That would produce a vertical waveform on the screen. Totally useless, it wouldn't have any sort of trigger functionality, but hey, it's theoretically doable with discrete components only. It could even have 3 channels easily. I can't emphasise this enough, this is a crazy, curious kind of idea, it would be pretty terrible as an oscilloscope.

author: Azhar
author_rank: Regular Contributor
timestamp: November 23, 2014, 07:04:27 am
content: Quote from: rs20 on November 23, 2014, 06:53:00 amwas thinking of something very simple and basic, not voltage read, uncalibrated display.maybe you are right, it is not easy to build such a circuit, thanks anyways.

author: Richard Crowley
author_rank: Super Contributor
timestamp: November 23, 2014, 07:05:09 am
content: What does "waveform" mean here? What frequency (or sweep-rate) are you looking for?Is this for some fixed waveform, or do you want variable sensitivity and/or variable sweep/resolution?Here in the 21st century, it may be easier to use a microprocessor and make a DIY DSO with a Raspberry Pi or something.

author: tautech
author_rank: Super Contributor
timestamp: November 23, 2014, 07:21:54 am
content: You might find enough to get you started here:http://homediyelectronics.com/projects/howtomakeafreesoundcardpcoscilloscope/

author: Azhar
author_rank: Regular Contributor
timestamp: November 23, 2014, 08:51:12 am
content: Quote from: tautech on November 23, 2014, 07:21:54 amThanks a lot! that's exactly what I was looking for! A Sound Card Oscilloscope
I need a diagram - Page 1
Forum section: electronics / beginners

author: ABDELAFOU
author_rank: Newbie
timestamp: August 29, 2025, 09:07:38 am
content: Hello, please, who knows or has the electronic circuit diagram for this educational board? Thank you. I cannot buy it, so I want to embody each part so that I can learn from it

author: Uunoctium
author_rank: Frequent Contributor
timestamp: August 29, 2025, 09:39:56 am
content: If you visit their homepage, you'll find a lot of information. At a quick search it seems, that an schematic of the complete board is not available but you can find some of the circuit parts with detailed explanations:https://ledlabs.uk/some-explained-schematics

author: SuperFlyEDSguy
author_rank: Contributor
timestamp: August 30, 2025, 06:46:27 am
content: It looks like they have a ton more schematics andprojectsall throughout their website. They also sell just thestandalone PCB, which you could save quite a bit (£115 less!) and then slowly work on building it section by section! From what I see, it’s Free Shipping, butonly to the UK.Either way, it wouldn’t hurt to just contact them and see what they could offer you with shipping, who knows, maybe they’ll give you a good deal?!Tell them that you’ve been discussing it on here, that could mean more business for them!I’m actually interested myself now because it looks fun and it would also be a great way to teach my son more about electronics! I wouldn’t be a potential customer now if you didn’t mention it and who knows who else may be interested as well?!
I need a Forum Moderator's Assistance - Page 1
Forum section: electronics / beginners

author: t1d
author_rank: Super Contributor
timestamp: July 08, 2020, 03:28:19 pm
content: I couldn't find where/how to report forum bugs. I am having trouble with my thread:https://www.eevblog.com/forum/beginners/researching-alternatives-to-dim-bulb-circuit-to-control-ac-current-while-testing/msg3125924/#msg3125924When I make a new post and attach a new image, the server is going back to my older posts and changing the old image to the new image??? Weird.Thanks for your help.t1d
I need a little help hacking a vacuum. - Page 1
Forum section: electronics / beginners

author: cl
author_rank: Newbie
timestamp: January 20, 2020, 11:21:02 pm
content: I have a few robotic vacuums I picked up at thrift stores for next to nothing. They are older ones and I would like to be able to attach them to an ESP8266 and control them over wifi from a computer. That is the end goal. The idea being to use the ESP to push the buttons and read if the LED's are active. Just trying to keep it simple.I tore one of them apart, tracing the (tac switches) buttons (clean, dock, max) It appears they are inline from pins on the SoC to ground. So the buttons just pull the lines low, Ill assume they have been debounced.I know I could use a transistor across the pins of the tac switch and use the esp to trip the transistor, making the connection to ground. That is the first thing that came to mind.What I am wondering is there a better way? Could I go digital pin on ESP to digital pin on SoC?Thank you

author: kernels
author_rank: Newbie
timestamp: January 21, 2020, 01:40:16 am
content: Tactile switches connected to microcontrollers often have a pull-up resistor and when you press the button, it pulls the pin to ground.The digital IO on most modern microcontrollers can be configured to work in open-drain mode (they will pull down to ground, but not pull up to vcc), so in theory one of these open-drain IOs can be used to connect directly to the vacuum cleaner switch line. BUT . . . it is a good idea to keep some level of isolation between the two circuits, so a transistor, fet or even opto-coupler would be a better solution.

author: james_s
author_rank: Super Contributor
timestamp: January 21, 2020, 01:49:59 am
content: Transistors are cheap, I'd probably just use them. If the vacuum microcontroller is 3.3V then you could probably connect them directly but 5V may fry the ESP8266, I don't know offhand if it is 5V tolerant.

author: cl
author_rank: Newbie
timestamp: January 21, 2020, 11:37:07 am
content: Thanks for the info,The SoC turned out to be an ARM STM32F071 processor and from the datasheet runs at voltages between v2.0 - v3.6The units have IR remotes and I have found what appears to be an ICP port on the main board. Im guessing there are lots of different ways to go about hacking this thing. lol(Shark Ion RV720 series)
I need a little Help with a 4011A Function Generator I purchased on evilbay  - Page 1
Forum section: electronics / beginners

author: ExodusEffects
author_rank: Contributor
timestamp: August 21, 2018, 03:21:13 am
content: It appears someone has been in side of the unit already trying to do some repair work I’m going to assume that Q1-4/Trimmer 1/4 will need attention. Looks like they did some soldering on that break out board Powers on but that’s as much as I know as of yet

author: t1d
author_rank: Super Contributor
timestamp: August 23, 2018, 04:35:27 am
content: You said that you are not sure, if the unit functions properly, or not. Then, you say that you are ordering new parts. I think there is a gap, here.I suggest you do some research and that you make certain your unit has a problem, before doing anything else:- YouTube... Search your exact make/model, for an operational tutorial. If there is nothing for your exact model, use the next closest model, in the line... A prior model, of your unit, or the next model, up, or down. If you find nothing, for your manufacturer, look at a generic tutorial, for Function Generators.- Search the net, for the operator's manual and the (separate) repair manual/schematic. The OM will have, likely, a procedure, to demonstrate the unit's functions. Often, you will find groups that are formed around your type FG and they have lots of expertise and information. Beware of sites offering to sell you the information. Keep looking; you will probably find it, for free. Also, beware downloading, from anybody that you are not certain is legit. Offering this type of information, is often a ruse, to giving you a virus. Another great source, for this information, is the manufacturer's website. If the unit is not too old, they will have, often, the exact information, you need, for download. If not, major repair houses and distributors, will, sometimes, share these documents.Bottom line, get the documents, for your unit, read them, determine if you have a problem, at all, then post, again, for help, with the problem. Best wishes.
I need a little help with a Yihua 853D soldering station  - Page 1
Forum section: electronics / beginners

author: KoolBreeze
author_rank: Newbie
timestamp: November 04, 2019, 03:58:33 pm
content: The hot-air gun handle says it's a 108D or based on it. I have one of these cheap 3 in 1's and I now believe it now to be a knockoff but it's affordable for now it works well except I don't have fan control so I changed the potentiometer with no effect started looking and found liquid either from a burst capacitor or something else not sure but what I want to do is bypass the PCB and wire the fan control directly to the potentiometer but I don't know which wires do what and all my searches end up showing me nothing usable then a question in this forum was a close match to my question yet it wasn't so now I have registered in order to ask you all for some help on determining how to complete the bypass. It uses a 3 wire B10K potentiometer. Everything except for the fan potentiometer works I cleaned the area with alcohol. Can a capacitor blow out the bottom? I know they are made to blow out the top and so I'm not sure if the liquid was capacitor juice or something else. I took some time to think about my next move. I have to pull the mainboard out and look underneath for a short if that fails, I will need to do the fan bypass. I even had to order a cheaper station to fix this station (lol) it arrives today. This station is new but it's not worth shipping it around to get fixed besides that I can fix this if I can figure out what wires on the hot air gun do. If you need more information please just ask I will do my best to answer. I am an old school PC hardware repair tech. I bought this station and a digital microscope to train myself for soldering SMD parts so I know a bit about how electronics work. Any help would be greatly appreciated...
I need a power supply with an output 24V and 5 A at least - Page 1
Forum section: electronics / beginners

author: Angel86
author_rank: Newbie
timestamp: June 30, 2015, 05:57:00 pm
content: Hi,First all, sorry for my english, I am not english speaker. I'm from Spain.I am new in that world and I reach this forum searching in Google for a Constant Current Driver for my LED project, but I think it is resolved.Now need a power supply for my project, an aquarium LED lamp . This is my project screenshoot:Sorry the interface is in Spanish.We can see that the project demands a power supply with 24 Volts and 4,54748 Ampers. I want at least 24V and 5A, but if it can be more ampers it could be better. I could to expand the project in the future but if it is 5A it is good.As I said I am new in that world, I want a power supply that it can be simulated on Proteus, to test it with simulation first.It is all.Thanks in advance to all for read my post and help me.

author: PSR B1257
author_rank: Frequent Contributor
timestamp: June 30, 2015, 06:06:47 pm
content: QuoteNo, you dont. Nobody is simulating a power supply, unless the simulation itself is the power supply.Switch mode power supplies with a nominal voltage of 24V and a nominal current of 5A will you find everywhere.http://www.ebay.es/itm/Fuente-Alimentacion-Alimentador-Transformador-24V-6-5A-/170428302418?pt=LH_DefaultDomain_186&hash=item27ae518452among thousand others

author: Ian.M
author_rank: Super Contributor
timestamp: June 30, 2015, 06:14:22 pm
content: Any commercial constant voltage 24V LED lighting supply rated at more than 125W will do the job. 150W supplies are common, or go for a 300W one if you are certain you are going to expand it.You will seldom if ever find SPICE simulation data for a PSU. Simply use a voltage source with some series resistance if you need to model droop with load, and check that the current doesn't ever spike above the PSU's rating.

author: Angel86
author_rank: Newbie
timestamp: June 30, 2015, 06:20:35 pm
content: Ok, sorry I thought you could simulate.Yes I know, but I want to do one and learn about Power supply, because I want to all the project by me.
I need a replacement part - Page 1
Forum section: electronics / beginners

author: Hextejas
author_rank: Frequent Contributor
timestamp: February 08, 2024, 03:39:59 pm
content: for this xformer and I have been unable to find something similar for less than $20.00.It goes into a desk lamp.When I had an electrician friend show me how to determine that it was faulty, he said something that made no sense to me. (not a surprise).Anyhow, he asked me for a new bulb and he said something about it being both AC and DC.?Apparently I had bought the right bulbs by accident.That dual voltages was a mystery to me and I think it might have something to do with the proper xformer.many thanks

author: BeBuLamar
author_rank: Super Contributor
timestamp: February 08, 2024, 05:44:38 pm
content: What dual voltage? The transformer is simply a 120VAC to 12VAC step down transformer. The light bulb should be 12V. I don't know if you can get the tranformer for less than $20. Prices have been increased quite a bit but the transformer should be easy to find a replacement.

author: reboots
author_rank: Regular Contributor
timestamp: February 08, 2024, 07:58:30 pm
content: Here are a couple of inexpensive 12V electronic power supplies which might work, if you're sure the transformer is bad.https://www.ebay.com/itm/276316962657https://www.amazon.com/dp/B015HLH4SM/If your lamp uses an incandescent bulb, it would work on either AC or DC. I think your friend was telling you that with the right bulb, it wouldn't matter whether you used an AC or DC 12V power supply.
I need a transformer calculation refresher! (Basic maths refresh) - Page 1
Forum section: electronics / beginners

author: WyverntekGameRepairs
author_rank: Regular Contributor
timestamp: December 23, 2019, 08:31:57 pm
content: Hi, I need a refresher on this subject because it has been a long while since I calculated transformer windings' specs.I thought it would be best to put it here so others can learn from it too.I need to relearn three different basic things:1) How to calculate the Primary:Secondary number-of-turns ratio2) How to calculate voltage change in respect to the P:S ratio3) How to calculate current change in respect to the P:S ratioThese three things are the basic fundamentals for transformer design, and are important to any hobbyist or person who wants to learn how to build or implement a proper transformer into their projects or designs. (Or if you are like me and need a refresher course to get rusty gears turning again). There are tutorials online, but I think that it is better that anyone can come here and get an answer too.

author: Jwillis
author_rank: Super Contributor
timestamp: December 24, 2019, 08:03:25 am
content: Google's awesome.http://www.learnabout-electronics.org/ac_theory/transformers01.php

author: vu2nan
author_rank: Contributor
timestamp: January 03, 2020, 05:37:39 am
content: The relationship is quite simple.Np / Ns = Vp / Vs = Is/IpWhere Np = primary turns, Ns = secondary turns, Vp = primary voltage, Vs = secondary voltage, Ip = primary current and Is = secondary current.Regards,Nandu.
i need help about placement of an external resistor - Page 1
Forum section: electronics / beginners

author: walidantar
author_rank: Newbie
timestamp: May 20, 2025, 07:40:09 am
content: hello, i need a little help about placement of 10k.ohm external resistors for gpio input pull-down with respect to pins, is it ok to put it after the pin? i want to save a little space a place the resistors underneath the board .. the application is scan switching diode matrix .. is it mandatory to place the resistor between the diode and the gpio pin or it's ok to let the resistor after the pin?

author: golden_labels
author_rank: Super Contributor
timestamp: May 20, 2025, 09:22:52 am
content: Yes, it is fine.It is exactly the same from electric point of view. At least as long as we talk about signals that slow andlumped-element modelholds.

author: PGPG
author_rank: Frequent Contributor
timestamp: May 20, 2025, 01:15:17 pm
content: Quote from: walidantar on May 20, 2025, 07:40:09 amYes. It is ok.It is perfect place to use SMD resistor.

author: walidantar
author_rank: Newbie
timestamp: May 20, 2025, 03:02:58 pm
content: thanks you
I need help choosing a proper connector. - Page 1
Forum section: electronics / beginners

author: DeadlyFoez
author_rank: Contributor
timestamp: June 03, 2016, 08:31:30 pm
content: Sorry if I'm in the wrong section, if so a mod could move this to the right section.I have been tasked with putting a connector onto some breakout boards so they can connect to some flat flex cables. There is 8 pins @ a 0.5mm pitch on the flat flex and the breakout board. Sadly, I can not find a CAD or schematic, or whatever the hell you would want to call it, for the breakout board to verify measurements for any connectors. I'm great at soldering and this will be very easy for me to do once I have the right connector.These is the breakout boards, obviously using the ones with the 0.5mm pitch.http://www.amazon.com/26mmx19mm-FPC-8P-0-5mm-2-54mm-Adapter/dp/B00O9Z09NU/ref=sr_1_fkmr0_1?ie=UTF8&qid=1444228439&sr=8-1-fkmr0&keywords=FPC+Connector+to+DIP8This is the flat flex cable.http://www.ebay.com/itm/181788970860?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AITAnd this is what I found for a connector to solder on, and with just a little eyeballing it looks like it would work but I would like someone with more experience to verify if it should be okay.http://www.digikey.com/product-detail/en/wurth-electronics-inc/68710814022/732-2019-1-ND/2060643The picture shows a 6 pin connector, but I'm sure all of you are used to digikey's generic pictures.I have only ordered from digikey one other time and it was a long time ago. Thank you all for taking the time to give me a quick hand with this.

author: uncle_bob
author_rank: Unknown
timestamp: June 04, 2016, 12:19:02 am
content: HiThe fancy name for what you are playing with is an FPC cable / connector. There is a multi layer problem here:1) The interconnect cable is a bit tricky to do.2) The connectors are a bit weird3) If you simply buy the cable, it tends to be connector speciificSimple answer is to pick both the cable *and* the connector at the same time. If you already *have* a connector on one end, you need to get some pretty good data on it. Might you get lucky? Sure, it's quite possible you will.Once you find a connector, you will likely have to do up a custom part for it in your layout program.Bob
I need help creating a toggle with a type D flip flop. - Page 1
Forum section: electronics / beginners

author: MarkS
author_rank: Unknown
timestamp: August 24, 2024, 11:34:54 pm
content: I'm having trouble deciphering the datasheet for the74HC74(<-clicky) flip flop. I am currently prototyping with Logisism. Using that, there is no combination of preset and clear that will give me a working toggle that starts with the Q output low, other than both preset and clear being held low. Any other combination does not toggle. According to the datasheet, this is an unstable configuration. The datasheet shows the clear line being set via a RC circuit as a POR, with set held high. That does not work in Logisism using its built in POR component. The problem for me is that it will be a couple of weeks before I can buy parts, so I am relying on the software to work. I do not know if this is the correct behavior of the chip, or a bug in Logisism's D flip flop component. I'm at my wit's end! NOTHING works except for the circuit that should NOT work. Can someone clear this up for me? I attached a picture of the working circuit from Logisism for reference.

author: Ian.M
author_rank: Super Contributor
timestamp: August 25, 2024, 12:00:41 am
content: Compare the 74HC74 datasheet's function table (page 11 of your link: Table 8-1) with that of the CMOS4013(page 10: Table 1). The 4013 matches your observed Logisism D flipflop behaviour because it has active high Set and Clear inputs. TTL D flipflops historically had active low Set and Clear therefore the 74HC74 has also (for 7474 functional compatibility), so unless Logisism has a specific 'x74 type D flipflop model, which would have active low Set and Clear inputs, you will need to add inverters in front of its generic D type's S and R inputs (for simulation only).

author: MarkS
author_rank: Unknown
timestamp: August 25, 2024, 01:05:51 am
content: Quote from: Ian.M on August 25, 2024, 12:00:41 amThank you! That was it. They do have a x74 chip and that worked.

author: MathWizard
author_rank: Super Contributor
timestamp: August 25, 2024, 07:52:23 am
content: In LTSpice, you can probably get models for that chip and a CD4013. Or try making the circuit with other logic chip models.I've made working SR latches, and a JK-flip-flop, and others, in LTS and on a breadboard, using just BC547's, and I think all 1k, 10k and 100k resistor's. They worked good enough, but I never used it in a project yet.