hybridfree/eevblog-posts huggingface dataset:
Need name of a switch - Page 1
Forum section: electronics / beginners

author: kahlenberg
author_rank: Newbie
timestamp: June 27, 2023, 12:57:37 pm
content: Hi,I need name of a switch for a project.https://www.pchub.com/acer-travelmate-2410-series-various-item-lid-switch-p63197Such switches are used normally for sensing closing of laptop lid.What is the name of this switch? It is not tactile switch, not limiting switch.Thanks.

author: wasedadoc
author_rank: Super Contributor
timestamp: June 27, 2023, 01:08:03 pm
content: Microswitch?

author: kahlenberg
author_rank: Newbie
timestamp: June 27, 2023, 01:25:44 pm
content: Unfortunately no, it is not micro switch. I think, this switches are linear, that means, when you press it, it doesn't generate any "click" sound.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 27, 2023, 01:34:32 pm
content: Maybe it's a "LID Switch," which appears to be a subclass of microswitch.https://www.google.com/search?q=lid+switch&oq=LID+switch&aqs=chrome.0.0i512l10.4118j0j15&sourceid=chrome&ie=UTF-8

author: kahlenberg
author_rank: Newbie
timestamp: June 27, 2023, 02:13:21 pm
content: It is lid switch, but I need part number only for switch, not with pcb and cable.Not necessarily this one. I need a part number of a lid switch.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 27, 2023, 02:25:50 pm
content: If the link you provided is to the correct switch, just buy the whole unit and use only the switch part. If that is not the correct switch, then we need a picture of the correct switch with dimensions.

author: TimFox
author_rank: Super Contributor
timestamp: June 27, 2023, 02:30:59 pm
content: "MicroswitchTM" is a Honeywell trademark for a brand of "snap-action switch".(like KleenexTM, Band-AidTM, PlexiglasTM, etc.)

author: Lord of nothing
author_rank: Super Contributor
timestamp: June 27, 2023, 04:18:39 pm
content: QuoteMaria?

author: kahlenberg
author_rank: Newbie
timestamp: June 27, 2023, 05:11:13 pm
content: Ok, found similar switches. The name is detector switchhttps://www.te.com/usa-en/product-2331369-1.html?q=jj%2Bseries&source=headerThanks.

author: liaifat85
author_rank: Regular Contributor
timestamp: June 28, 2023, 11:25:43 am
content: It is written Lid switch in the description.

author: Terry Bites
author_rank: Super Contributor
timestamp: June 28, 2023, 12:09:32 pm
content: Wow, how long have Honeywell had a hold on that! 1950 I hear.I bet someone claims Wires™, probably appple. No, I tell a lie. It's Yaesu.I'm registering OverPriced™ before its snapped up. Probably by apple.

author: TimFox
author_rank: Super Contributor
timestamp: June 28, 2023, 01:42:16 pm
content: Quote from: Terry Bites on June 28, 2023, 12:09:32 pmHoneywell invented the snap-action switch in 1932 and named it the Micro SwitchTM.The reason I mentioned the generic term "snap-action" was that novices often don't know the term-of-art for a given type of device to look up.If you patent the Wire, there may be prior art to deal with.
need part a GND Wire - Page 1
Forum section: electronics / beginners

author: generic_username
author_rank: Regular Contributor
timestamp: December 18, 2015, 08:16:57 am
content: Hi everyone,I hope I can somewhat decribe what I need.Up till now I had for my PCB's a part of the GND as a wire on top of the board so I could easily connect my oscilloscope probe to it.It was basically 2 vias for the cable and then I pluged in a bare copper wire.My question is is there a part that does excatly that, I tried searching for it but as english is my second language I'm in a bit of a loss.thx in advance______ <- bare wire - GND| |----------O------O---------------board^| viaMy Amateur try to describe the part in ASCII Art

author: Ian.M
author_rank: Super Contributor
timestamp: December 18, 2015, 08:22:13 am
content: http://www.digikey.co.uk/product-search/en/test-and-measurement/test-points/2294346

author: generic_username
author_rank: Regular Contributor
timestamp: December 18, 2015, 08:23:12 am
content: exactly what I Need thank you
Need parts suggestions for a computer fan type air circ system - Page 1
Forum section: electronics / beginners

author: bradleyheathhays
author_rank: Newbie
timestamp: March 30, 2017, 06:19:26 pm
content: I'm designing a small air circulation system (not computer related) where I need to use two computer type fans and some type of fan speed controller, and I need some advice on what parts to get.Requirements for the fan..- 120 or 140 mm- as quiet as possible- moves as much air as possible (hopefully in the 70+ cfm range)- ball bearings, not sleeveI've done some looking around on newegg, etc and found some good candidates, but if anyone knows of a good brand that's long lived, quiet and moves lots of air please let me know.And as far as supply power and the speed controller are concerned, I'm entirely open to your ideas. Being a novice I'm guessing there are probably better parts suggestions that what I've imagined so far. The power will be coming from 110v so I'm gonna have to convert that somehow. I have a janky little adapter box that plugs into a 110v outlet and outputs to a female 12v car adapter, so that would probably work. Although I'd like a more solid electrical connection than the male in female socket of this adapter would provide.And for the controller I'm thinking a simple light dimmer from home depot might do the trick.Thanks for helping, I'm all ears..

author: james_s
author_rank: Super Contributor
timestamp: March 31, 2017, 08:33:52 pm
content: Any random 12VDC "wall wart" or cord lump style power brick will work fine, so long as it's rated for at least as much current as the fans draw. You can get these for peanuts at thrift stores or garage sales if you don't already have some.You'll definitely want a PWM speed controller for the DC side, you can buy them ready made or you could build something yourself. If you look on ebay or alliexpress you'll probably find a selection of different inexpensive modules that will do what you need. The Chinese are quite good at coming up with handy little electronic modules.

author: BurningTantalum
author_rank: Frequent Contributor
timestamp: April 01, 2017, 03:54:14 am
content: Be aware that the PC type axial fans are not good at shifting air in ducts, so it may be an idea to lash up the system running flat out to check the operation. Centrifugal type fans provide much higher pressure to move air through a resistive duct. I'm not sure how much space you have for installation but maybe a unit from a cooker extractor could be useful. It would certainly be of better quality and longevity.BT
Need potentiometer advice! - Page 1
Forum section: electronics / beginners

author: rhubarb
author_rank: Newbie
timestamp: March 16, 2022, 03:25:33 pm
content: Hi EEVBLog!!I'm in need of your valuable help againI've been using these potentiometers with push/pull DPDT's attached for ages nowBut I recently came across an eBay listing that piques my curiosity - It was a pot serving similar function but quite a bit slimmer and more PCB friendly (see pic ) - two really important things for a project i want to whizz up.But I'm having a problem sourcing any that meet my specific requirements. I need:a pot value of anywhere between 220k and 500k1 or 2 gangand a DPDT switch (either push/pull or push/push)a short, splined shaft (around 15mm?) same as in pic 1I've searched high and low through distributors, manufacturers sites, and listings but no joy.The main manufacturer of pots in that style seem to be Alps Alpine by my research but even they don't make pots with a DPDT anymore accoording to their website. Which saddens me to no end.If anyone could drop the names of any pot manufacturers that make them in that nice slim style so I can go and comb through their site, I'd be madly appreciative!!All the bestRhubarb

author: Ed.Kloonk
author_rank: Super Contributor
timestamp: March 16, 2022, 04:17:14 pm
content: Is this any use to you?https://www.bourns.com/docs/Product-Datasheets/PDB183-GTR.pdfhttps://www.digikey.com.au/en/products/base-product/bourns-inc/118/PDB183/121300

author: rhubarb
author_rank: Newbie
timestamp: March 16, 2022, 04:24:16 pm
content: those are the ones i'd already been using, i'm looking for something slimmer like in the pic.Thanks for the suggestion though

author: Terry Bites
author_rank: Super Contributor
timestamp: March 16, 2022, 05:04:47 pm
content: have you had a look at the ALPS selection?https://tech.alpsalpine.com/prod/e/html/potentiometer.html

author: rhubarb
author_rank: Newbie
timestamp: March 16, 2022, 05:18:44 pm
content: I have. No luck thoughdon't seem to make any DPDT options listed on their website which is curious because this ebay listing says otherwisehttps://www.ebay.com/itm/283796890759

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: March 16, 2022, 08:54:25 pm
content: If your quantity is enough Alps would custom make parts at a reasonable price last time I checked.Jeff

author: rhubarb
author_rank: Newbie
timestamp: March 18, 2022, 10:30:21 pm
content: Aha! Now that’s worth knowing. I wonder how much I’d have to be willing to pay? Ill do some research. Thanks!!

author: mc172
author_rank: Frequent Contributor
timestamp: March 18, 2022, 11:01:36 pm
content: The device in your picture is made by ALPS, specifically part of their RK097 range. There are off the shelf options available in DigiKey/Mouser etc.https://tech.alpsalpine.com/prod/e/pdf/potentiometer/rotarypotentiometers/rk097/rk097.pdf
Need Power Supply for macbook logic board repair - Page 1
Forum section: electronics / beginners

author: Vietk123
author_rank: Contributor
timestamp: August 19, 2016, 06:11:32 am
content: I am new to the forum and find a lot of useful info here thanks all. I am looking for a bench power supply. I am mainly focusing on macbook logic board repair and iphone logic board testing and repair. What is a decent brand bench power supply should I be looking for? My budget is around 150-200 if need to be. What voltage and amp should i be looking for? I know this question might be answer already have I did search youtube and google and this forum but get mix result. I would love some feed back of you guys thanks in advanced and good to learn from you all.

author: jeroen79
author_rank: Frequent Contributor
timestamp: August 19, 2016, 09:06:18 am
content: The required volts and amps would be dictated by your work.What voltages are used on the apple logic board and how much current does each line use?Are you going to isolate parts so you only need low current or will you have to power everything on the same powerline?
Need rail to rail opamp - Page 1
Forum section: electronics / beginners

author: jeet55
author_rank: Contributor
timestamp: September 10, 2017, 04:09:08 pm
content: For a project that iam currently working it needs rail to rail opamp . So i have no idea regarding part number. So can some one please suggest me commonly available rail to rail opamp.Required: input voltge +5v single supplyOutput should to 5 volts or near to it like 4.8Output current :need to drive mosfets and pins of microcontroller (adc) so not much current needed.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 10, 2017, 05:03:28 pm
content: There are lot's of RR OPs for a 5 V supply. A MCP6001/2/4 would be a rather cheap one.Most AZ OPs for 5 V are also rail to rail if precision is needed.Usually one would use something like the parametric search at the supplier of choice.

author: Benta
author_rank: Super Contributor
timestamp: September 10, 2017, 05:49:17 pm
content: For applications not needing a lot of bandwidth, LMC6482 is my favourite, which I've used in lots of projects. It's a dual, though.

author: bson
author_rank: Unknown
timestamp: September 11, 2017, 08:29:52 pm
content: You don't say what kind of bandwidth or slew rate you need. RRIO op amps tend to compromise in these areas for ease of use. The TLV172 for example drops to 0.3MHz GBWP within 2V of its positive rail, with equally poor slew rates, but otherwise is RRIO with no latching or phase inversion effects. If you're sampling very low bandwidth signals, such as a temperature sensor or a fuel gauge, then this is no problem. So it really depends on what your application is.

author: Zero999
author_rank: Super Contributor
timestamp: September 11, 2017, 09:38:23 pm
content: Is that rail-to-rail output or do you need it on the input too? If so, does it need to go to both rails or is just the positive fine?If all you need is an op-amp which can output voltages, all the way up to +V, then a standard op-amp, with a current source, connected the output will do.What's load impedance?By the way, don't bother simulating the attached circuit. The op-amp models don't accurately depict what will happen if the output is pulled-up. See the following thread for more information, if you really want to simulate it.https://www.eevblog.com/forum/projects/better-ltspice-tl072-model/msg999066/#msg999066
need recommendation for tool to proper 'seat' wires in this connector type - Page 1
Forum section: electronics / beginners

author: sanman
author_rank: Contributor
timestamp: April 10, 2019, 04:42:05 pm
content: Can anyone recommend/point me to the proper type of tool to properly 'seat' the wires into these types of connectors?Thanks for the help!

author: helius
author_rank: Super Contributor
timestamp: April 10, 2019, 05:22:47 pm
content: That is called an IDC (insulation displacement connector). The proper tooling is called a "punch-down tool".You need a tool with the proper sized blade for the connector, which differs between manufacturers. You will need to identify the model of connector to find it.For example, for Amplimite HDE connectors you can use the TE 91287-1 tool, which is a very basic manual tool. Other types of tool may have spring assist, wire cutters, or levers or automatically index the connector as you insert wires.

author: sanman
author_rank: Contributor
timestamp: April 10, 2019, 05:38:54 pm
content: Thanks Helius. Based on your information. I will do some research and see what I can find

author: reboots
author_rank: Regular Contributor
timestamp: April 10, 2019, 08:58:35 pm
content: That looks very much like a TE MTA-series connector (or clone) to me. Measure the pitch between the two pin centers: 0.1" (2.54mm) would be MTA-100, while 0.156" (3.96mm) would be MTA-156 (picture attached).Following helius's good advice, here's the official punchdown tool for MTA-100:https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/59803-1/A9982-ND/132430MTA-156:https://www.digikey.com/product-detail/en/te-connectivity-amp-connectors/59804-1/A9981-ND/132433Rather expensive for what they are, but you may be able to find them for a few dollars cheaper through other distributors.

author: ArthurDent
author_rank: Super Contributor
timestamp: April 10, 2019, 10:42:03 pm
content: If you're only doing one or a few connectors, rather than buying the proper expensive tool, I've used a back side of a butter knife or a thin flat bladed screwdriver to carefully push the wire into the connector. Just make sure what you use isn't so wide that it spreads the two halves of the connector and you end up with a poor contact.
Need recommendations on polyswitch resettable fuses for ATX power supply build. - Page 1
Forum section: electronics / beginners

author: dennisyuki
author_rank: Contributor
timestamp: July 17, 2014, 07:49:27 pm
content: I want to build a ATX converted bench power supply.I like this instructional video by Great Scott.But he does not use any fuses on the power lines.I know seeed sudio sells this break out board with polyswitch resettable fuses on the power lines.http://www.seeedstudio.com/depot/ATX-breakout-board-bench-power-supply-p-1222.htmlI like the idea, but I want to build everything in the atx case with resetable fuses using a through hole package.I looked on octopart and found some fuses but cant find any through hole resettable fuses with the same specs as seedstudio.My question is what would be an acceptable spec for a through hole resettable fuses for this project. ie trip amperages, etcAnother questions. Seed studio basically uses one wire for each power line, ir 5v, 12, 3.3, for each output post. But great scott cuts all the lines and bundles all the like kind voltage lines together. what does that do the amperage? ie 1 wire of 5 volts = 2 amps, 2 wires bundled of 5v= 4 amps, etc. Am I thinking of this correctly for the amperages?Also, any tips or other plans that are better I would be open to suggestions.Thanks.

author: kingofkya
author_rank: Regular Contributor
timestamp: July 17, 2014, 08:55:45 pm
content: You might be better off looking up an adjustable current limit circuit there are tones of them useing a lm317. If its a lab supply you want to be able to varied it so you can adjust it so you don't blow something up if you short something on a new board or something like that. For some things you might want 10ma limit others you might want 2amps.https://www.google.com/search?q=lm317+current+limiter&espv=2&source=lnms&tbm=isch&sa=X&ei=YDfIU9_xBZLyoAT-6ILACg&ved=0CAYQ_AUoAQ&biw=1236&bih=833cheap souse for parts.http://www.taydaelectronics.com/catalogsearch/result/?q=POTENTIOMETERhttp://www.taydaelectronics.com/lm317t-lm317-voltage-regulator-ic-1-2v-to-37v-1-5a.html
Need Regulated Power Supply circuit using LT1074 Buck Regulator - Page 1
Forum section: electronics / beginners

author: techguru
author_rank: Regular Contributor
timestamp: November 26, 2017, 05:52:50 pm
content: Hi to all,I want to design 0-24V dc @ 3Ampere rating. Could any body suggest me the CV/CC circuit using buck regulator LT1074. Have a nice evening.

author: hugo
author_rank: Regular Contributor
timestamp: November 30, 2017, 12:13:44 am
content: There you go guru:http://www.changpuak.ch/electronics/PETH-581.php
Need rotary switch 7 positions 4 poles - Page 1
Forum section: electronics / beginners

author: soldar
author_rank: Super Contributor
timestamp: January 04, 2024, 03:56:23 pm
content: I have a hot plate for cooking and the rotary switch, which was crap, failed. The contacts need to control just under 4A and they were undersized. It is an old proprietary switch and no way to find an exact replacement.I need to control 4 poles and for now I am using 4 individual switches and it works but I need to have a reminder card to know what switches to open or close for each power setting.I could use a 7 or 8 position, 4 pole (4 deck), rotary switch rated for 4 or 5 Amps. The contacts need to switch a max of 4 A at 230 Vac from mains but everything I find is just too expensive and not worth it. This is just a cheap hot plate and I am not going to spend more than it is worth.Or maybe there is some easy way to control the 4 switches with rotary cam wheels.Any ideas?

author: themadhippy
author_rank: Super Contributor
timestamp: January 04, 2024, 05:35:31 pm
content: 4 relays and a stock 1 pole rotary switch,use 240v coil relays and no additional psu needed.Of course all depends how much is too much.

author: sparkydog
author_rank: Regular Contributor
timestamp: January 04, 2024, 05:55:05 pm
content: Yes, as noted, I have a feeling you're better off using relays (or triacs!) and an alternate control scheme. 4A seems to be a lot of current for a rotary switch; you're asking to put almost 1kW through it. Sure, for "simple" variants (e.g. 1-deck, 3-position) you might find those and they might be reasonably priced. Otherwise, the only option I'm even seeing is NKK Switches HS16-4N which is going to set you back >$70.Honestly, your lowest-BOM option might be to use a pot and an MCU... at which point you might consider adding a thermistor/thermocouple so you can actually control the temperature.

author: soldar
author_rank: Super Contributor
timestamp: January 04, 2024, 07:59:07 pm
content: Thank you both. As I said, I have it working with four simple switches and this is just an attempt to improve it, especially so I don't have to explain to others the complicated scheme of hand switches. I'd rather stay away from relays and such but if I went that way I would rather go with electronic relays than mechanical.It seems to me the switches for resistive cooking elements are way undersized and fail often.If I had more interest in this maybe I could try to build myself some wheels with cams that actuated four switches but I probably not finish it.

author: _EDMAR_
author_rank: Newbie
timestamp: January 05, 2024, 06:32:51 pm
content: My Dad was a great Tesla fan. I have acquired most of his older electronics from the '50s '60s '70s.I don't have the specs for most of what I have.But these wafer-switches were fun to play with when I was kid.
Need Snubber Recommendation - Page 1
Forum section: electronics / beginners

author: scott216
author_rank: Regular Contributor
timestamp: December 19, 2013, 12:24:12 am
content: I have a hot tub heater that is turned on by a contactor. I have an Arduino that monitors and controls the hot tub and I'd like to reduce the electrical noise generated by the contactor when the heater turns on. I figured a snubber across the contactor contacts would help, but I don't know how to spec the snubber. The load is resistive, 220 VAC and 22 amps. I'd appreciate any snubber recommendations.

author: SeanB
author_rank: Super Contributor
timestamp: December 19, 2013, 04:42:21 am
content: You can buy a snubber network off the shelf, but typically they use a 100-470nF 400v mains rated capacitor and a series resistor of 10-47R 1W, all across the contactor contacts.

author: Kremmen
author_rank: Super Contributor
timestamp: December 19, 2013, 06:22:32 am
content: Have you considered replacing the contactor with a solid state relay? 22 amps is well within the rating of a typical brick SSR, and those would not only avoid sparking and mechanical noises, they will also be zero point switching thus avoiding most if not all EMI issues.

author: scott216
author_rank: Regular Contributor
timestamp: December 19, 2013, 02:11:06 pm
content: Quote from: Kremmen on December 19, 2013, 06:22:32 amI may do that. But I don't want to get a cheap SSR, I've read about the cheap ones not turning off too easily.

author: Kjelt
author_rank: Super Contributor
timestamp: December 19, 2013, 03:08:11 pm
content: Snubber is mostly against arcing, thus lifetime of relaycontacts. A 275V MOV across each relay contact would also do the trick.But I would also go for a nice zeroswitching SSR rated at at least twice the amps you switch and an appropriate heatsink.

author: 13hm13
author_rank: Frequent Contributor
timestamp: December 19, 2013, 03:55:45 pm
content: The snubber may, in certain digital ckts, not be placed around each diode, but rather across the transformer secondary, which is often better. Readthis articlefor more info.

author: minime72706
author_rank: Frequent Contributor
timestamp: December 19, 2013, 04:16:15 pm
content: Anything that manages to call itself a SSR should not have any trouble avoiding commutation failure (turning off when you want it to) with a resistive load.A zero-crossing device is not a bad idea at all, also because the load is resistive.If you want to use a snubber network, I would simply "wing it" with a 0.47uF X2 capacitor and maybe like a 33 ohm power resistor.I was going to suggest a MOV yesterday, but then I figured that I'd have to see how high voltage the noise is. Then I thought "well it can't hurt". I would use one (or more) with a rating somewhat close to your supply voltage so that it actually catches spikes. 250VAC or 275VAC

author: 13hm13
author_rank: Frequent Contributor
timestamp: December 19, 2013, 04:38:18 pm
content: For certain "audiophile" ckts, I place snubbers across many 3-pin regs, and even V+ and ground of certain opamps.http://www.diyhifi.org/forums/viewtopic.php?p=8047http://www.diyhifi.org/forums/viewtopic.php?f=5&t=1779
Need some capacitor advice with rail splitter/virtual ground - Page 1
Forum section: electronics / beginners

author: mkaluza
author_rank: Contributor
timestamp: December 05, 2020, 03:55:28 pm
content: Hello guys!I'm building a rail spliter for my project and I've come up with this so far (attachments)I mostly followed thishttps://www.tubecad.com/2018/02/blog0412.htmand Horowitz,Hill Art of Electronics.The circuit works for dc, but without any caps I get oscillations on the Vout of about 6MHz, 200-400mVpp when I load it with anything more than few mA. Those I put there fix things, but I don't really know why... Could you help me with placing right caps in right places?To put this into perspective:- I need the rail splitter for my Poor Man's Signal Generator that I'm building,- It will be powered at 28-36V from a XL6009 boost converter board you can get from Aliexpress, which in turn is powered from whatever I have laying around - from laptop power brick to an usb phone charger.- at some point I'd like it to be able to drive 50Ohm line, so it should be able to handle at least +/-150mA- generator will probably output 1MHz max if that is important- output will be DC coupled.There will be also a buck converter (also cheap board from Ali) between those 28-36V and the virtual ground generating 5V for the logic part - display, serial and stm32f103 board (blue pill), which does the UI and feeds the DAC.So I need this to have a ground reference for the cpu, dac and opamps (and output obviously).I hope at least some of it makes sense...Cheers,Marcin

author: fcb
author_rank: Super Contributor
timestamp: December 05, 2020, 04:03:01 pm
content: Post your LTSpice(?) model. Have you built it, or just modelling it at the moment?Have you tried a Zobel network on the output?edit: can you post the BD139/140 models as well.

author: Zero999
author_rank: Super Contributor
timestamp: December 05, 2020, 06:51:05 pm
content: Just embed the models in the .asc file.I'm not surprised it's oscillating, with the BJTs on the output., in common emitter configuration. Why not use emitter followers, which are mode stable?

author: mkaluza
author_rank: Contributor
timestamp: December 05, 2020, 10:40:26 pm
content: @fcb didn't think of that, sorry. Don't have access to my pc now, but I used thishttp://ltwiki.org/index.php?title=Standard.bjtYes, I built it, but only on the breadboard. I saw those oscillations on the scope.Haven't heard of Zobel network before - I'll have a look, thanks@Zero999 I'll do that next time, thanks for the tip (that's my first contact with ltspice, so there's still much for me to learn)The reason for adding that lat pair of transistors to the "diamond" circuit was that I saw something similar in Art of Electronics (and I needed more current/power on the output).
Need some clarification on this circuit - Page 1
Forum section: electronics / beginners

author: subhadeepbiswas!
author_rank: Newbie
timestamp: October 08, 2017, 07:15:08 am
content: I'm making an amplifier which supports USB and Bluetooth as well. The bluetooth device I've used is an USB device. So I connected both the device in parallel and used a DPDT switch to interrupt the 5V power lines of the USBs so that one remains on and other idle at a time and vice versa but that didn't work the USB controller is not recognizing any of the USB devices. I did some research on this and then connected the DPDT with the D+ and D- pins of the both USBs by doing this the controller is recognizing only one USB (mostly the sd card reader not the bluetooth device) so I'm thinking to turn on/off both D+ and D- pins digitally using transistors I'll use the dpdt switch to apply the voltage to the base of the transistors that would select one of the USBs at a time.Here is the circuit I've designed. Will it work? please tell if the design is correct/wrong or I've missed something? Thank you.
Need some help on Blue ESR meter assembly - Page 1
Forum section: electronics / beginners

author: SmallWalrus
author_rank: Contributor
timestamp: February 14, 2012, 11:57:16 am
content: Hi all,Sorry in advance for my extremely noob-cake questionsI got myself a Blue ESR meter lately, and got a bit stumped with the final bit of its assembly.To make it easier for you guys to see what I mean, here is how it looks like now:I managed to figure out where the two variable pots go as well as the 2 blue LED lights, however what got me are 3 little capacitors. The ones that are 22uF, 33nF and 0.47uF.There are two 22uF capacitors on the schematic, and the bigger one I have soldered on, but the smaller one seems a bit too big for the big rectangle there. Have I gotten them mixed up? Also, which of the leads is for the positive terminal? (The positive sign is printed in the middle in between the two leads).I also can't seem to figure out the remaining two capacitors. The little green blocky one has the code "K63 1817 F1103" which I can't seem to plug into any online calculator at all, while the other smaller brown one has "16L 3333" printed on it, which gave me the same problem.Isn't it supposed to be a 3 letter code? How are these codes supposed to be interpreted?

author: Psi
author_rank: Super Contributor
timestamp: February 14, 2012, 12:06:09 pm
content: The pcb footprint that says "22uF BP" probably means "Bi Polar"If that's correct then it's a bipolar electrolytic, so doesn't matter which way around it goes.That also may explain why the + is in the middle.Check the capacitors you have, if any are bipolar electrolytic they will be marked as such or will be missing the typical negative signs down the side.

author: amyk
author_rank: Super Contributor
timestamp: February 14, 2012, 12:21:02 pm
content: Going by size andother people's pictures of their meter, the 0.47uF should be the green block, and the 33nF the smaller one.
Need Some Help Please - Page 1
Forum section: electronics / beginners

author: tony3d
author_rank: Frequent Contributor
timestamp: October 08, 2013, 01:51:24 pm
content: I'm on experiment 10 in the Make Electronics book. I understand what's going on with the transistor being used as a switch, but I'm confused by the mA readings I'm getting. There are suppose to be 3 resistors in the circuit, I'm using 4 (two in series a 217, and 463 ohm) to get the required 680 ohms. There is then another 9,870ohm, and a 217 ohm. for a total resistance of 10767 ohms. Using Ohms law, that would come out to about .0011 amps or 1.11 mA's correct? My circuit actually is drawing about 11.06 mA's. Is that because the transistor is actually amplifying the current? This is all based on 12 volt input.

author: Dave
author_rank: Super Contributor
timestamp: October 08, 2013, 01:54:43 pm
content: Draw the schematic (or just scan it from the book) and we will be able to tell you.Don't forget to draw in the ammeter and the values of the resistors you are using.

author: rexxar
author_rank: Frequent Contributor
timestamp: October 08, 2013, 02:03:09 pm
content: You've counted the resistor on the base in your calculations. It's not actually part of the current path. What you should be concerned with are the resistors from 12V to the collector, and the one from the emitter to the load. If you add those two, you get 860 ohms, and at 12V that's 13.9 mA, which is close enough to the 11 that you're seeing.

author: tony3d
author_rank: Frequent Contributor
timestamp: October 08, 2013, 02:05:41 pm
content: Quote from: Dave on October 08, 2013, 01:54:43 pmHere you go.

author: tony3d
author_rank: Frequent Contributor
timestamp: October 08, 2013, 02:12:35 pm
content: Quote from: rexxar on October 08, 2013, 02:03:09 pmOk, I see. So I need to be looking at the two 217's, and the 463. That's 897. That gives me 13.38 mA's. So, this is because the voltage at the base just opens the path through the other 3 resistors connecting the collector with the emitter, and the 9,870 ohm resistor is just there to control how much current the base gets? So why am I getting a difference of 2.32 mA's? Is it because of the LED?

author: rexxar
author_rank: Frequent Contributor
timestamp: October 08, 2013, 02:17:56 pm
content: Quote from: tony3d on October 08, 2013, 02:12:35 pmExactly.

author: tony3d
author_rank: Frequent Contributor
timestamp: October 08, 2013, 02:23:15 pm
content: Quote from: rexxar on October 08, 2013, 02:17:56 pmWow! That is so cool.

author: rexxar
author_rank: Frequent Contributor
timestamp: October 08, 2013, 04:28:27 pm
content: Quote from: tony3d on October 08, 2013, 02:23:15 pmIf you think about electricity as water flowing through a pipe, a transistor is basically a valve. The more current you apply to the base, the more 'open' the valve is. If you put a larger resistor there, you should see the current go down. I think in the next experiment, you replace that resistor with your finger. The resistance across your skin is several megaohms. See how much current you get out with that big a resistance going to the base.
Need some help understanding this AC LED driving circuit - Page 1
Forum section: electronics / beginners

author: sporadic
author_rank: Regular Contributor
timestamp: November 14, 2012, 03:20:14 pm
content: Christmas lights of course! Traditionally, I believe these were just half-wave rectified strings. This string I have however has a little partially rectified parallel RC circuit going on that seems to adjust the voltage differential based on how man LEDs are in series, always keeping peak current within the safe ranges regardless of the length of the LED string (provided there's enough voltage to drive them). I've attached the schematic along with plots from LTspice for 50 LED and 26 LED count sims. I've been reading up on AC stuff herehttp://www.allaboutcircuits.com/vol_2/index.html,but am not wrapping my head around the math yet. Anyone care to explain to me what is going on or point me in the right direction? Would it be possible to drive 26 LEDs with this same circuit and not damage them? Thanks!Legend for the AC plots (ground in respect to L):Green - Voltage reading at F1 (US mains)Blue - Voltage reading at V+ (beginning of string)Red - Voltage reading at V- (end of string)Cyan - Current flowing through R2Legend for the DC plots (ground in respect to V-):Green - Voltage reading at V+Blue - Current flowing through R2

author: Colin55
author_rank: Contributor
timestamp: November 15, 2012, 08:30:49 am
content: It's a very clever CONSTANT-CURRENT voltage-doubling design.It produces up to 300v on a 120v supply and the current is 25mA.The amazing thing is, you can put any number of LEDs on the output, up to 80 white LEDs.

author: Zero999
author_rank: Super Contributor
timestamp: November 15, 2012, 10:40:31 am
content: Why break the circuit up into three pieces when it's easier to read as one?Perhaps that's why you're having difficulty understanding it.

author: Alana
author_rank: Frequent Contributor
timestamp: November 15, 2012, 02:01:10 pm
content: LEDs would have to be back-to-front paralell in order for it to work. Bug in schematic drawing?

author: sporadic
author_rank: Regular Contributor
timestamp: November 15, 2012, 02:18:55 pm
content: Figured it all out with the help of this thread:http://doityourselfchristmas.com/forums/showthread.php?23028-Need-some-help-shortening-these-new-LEDsand learning about capacitive reactance.As for breaking up the drawing, it represented the physical product. Two plugs with a removable string of LEDs. I didn't have issues following it like that.Circuit was spot on, just my AC knowledge wasn't
need some help with Randy Slone's power supply in Tab Guide To Understanding... - Page 1
Forum section: electronics / beginners

author: mmknee
author_rank: Newbie
timestamp: April 21, 2012, 12:42:52 am
content: I have several questions for someone a lot smarter than me... I am trying to put together a parts list for this power supply, and I want to order everything I need to finish it at once, first is the bridge rectifier, it calls for a 6 amp 200 volt PIV bridge rectifier. The only ones I have found with those values are for PCB mounting, not chassis mounting. Later on it calls for a 0.1uF Ceramic Disk capacitor, but gives no value for voltage... HELP pleaseC3 and C4 are the caps I was talking about in this schematic, the other image is a overall schematic

author: TerminalJack505
author_rank: Super Contributor
timestamp: April 21, 2012, 01:14:47 am
content: It looks like the most voltage that those caps are going to handle is about 2.4V. So caps rated at 6.3V or better should work. Personally, I'd probably just use 25V or 50V caps. That's the voltage rating most through hole caps will be for that size.So far as the bridge rectifier goes... you might have to settle for using a PCB mount part. It looks like the project is going to have a perfboard for the smaller components, anyway. So you can just use a little bigger board and throw the bridge rectifier on it.

author: mmknee
author_rank: Newbie
timestamp: April 21, 2012, 01:21:03 am
content: wonderful and thank you!! I appreciate the help!!
Need some help with some material  - Page 1
Forum section: electronics / beginners

author: martysdomain
author_rank: Contributor
timestamp: May 13, 2011, 01:55:51 am
content: I am a past engineering student (AAS in EE) reviewing the material for the GROL FCC test, elements one and three. I have seen a good majority of the example problems in school (about two years ago), and work, but I am hung up and have a hard time understanding this one.I need to find Z (impedance) for a circuit, in rectangular form. Frequency is 50KHz, and the two components in the circuit are a 0.01uF capacitor in parallel with a 300Ohm resistor. I calculated Xc to be 318.3 Ohms. I am unsure as to where to go from here, or how to arrive at Z. The solution is 159-j150. Thanks a million, I hope someone can help.

author: sacherjj
author_rank: Frequent Contributor
timestamp: May 13, 2011, 03:23:07 am
content: Resistance in Rectangular form is 300. Capacitive Reactance is 0 - j318.3Let's check that. Xc = 1/2 Pi F C = 318.3 That looks good.The resulting Inductance is Z = 1 / ( 1 / R + 1 / -jXc)If I remember correctly, this expands toZ = (R * Xc^2) / (R^2 + Xc^2) - j (R^2 * Xc) / (R^2 * Xc^2)Z = 30394467/191314.89 -j 28647000/191314.89 = 158.9 - j149.7Edit: Did a search and found a resource that explains it better:http://www.play-hookey.com/ac_theory/ac_rc_parallel.html

author: martysdomain
author_rank: Contributor
timestamp: May 17, 2011, 11:23:41 pm
content: Thank you. I worked through the problem this evening, and checked out the link that you had provided. I feel a little bit better about operating around the imaginary numbers now.
Need some help with this LCD controller IC. - Page 1
Forum section: electronics / beginners

author: Refrigerator
author_rank: Super Contributor
timestamp: December 24, 2015, 02:40:22 pm
content: So i found an old DVD player, the screen still works and i found the datasheet for the LCD controller ( VX1828 , PDF can be downloaded here:http://www.vxis.com/info.htm) and according to the datasheet it accepts s-video but i got completely lost when i saw the pinouts.I want to put composite video in but i don't know where ?

author: bktemp
author_rank: Super Contributor
timestamp: December 24, 2015, 03:41:34 pm
content: Quote from: Refrigerator on December 24, 2015, 02:40:22 pmI wouldn't call that a datasheet. It only gives a overview, but is completely useless if you really need to control this ic.QuoteThis ic needs some configuration from the host. The ic has several composite and S-video inputs, but you need the complete datasheet to configure the the wanted input format.AIY0-3 are the composite or Y input and AIC0-1 are the C inputs used together with the Y inputs for S-video. Without the complete datasheet you can only use the input configured by the processor from the DVD player.

author: amyk
author_rank: Super Contributor
timestamp: December 25, 2015, 07:20:19 am
content: The complete datasheet is here:http://www.daxia.com/bibis/upload/0VX1828B_Datasheet02.pdf(Also attached for future reference.)It has an I2C interface and you can select the input using register #2. The DVD player's CPU probably configures it to use one of the inputs on power-up, but you can add your own MCU to the bus to issue the appropriate commands to select the other inputs.Edit: also attached some source code for interacting with this LCD controller. Appears to be for Nuvoton/Winbond W78E65 MCU.

author: Refrigerator
author_rank: Super Contributor
timestamp: December 25, 2015, 10:14:25 am
content: Quote from: amyk on December 25, 2015, 07:20:19 amThanks alot.
Need some precision parts for reference / testing / calibration - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: August 15, 2018, 11:12:50 pm
content: What should I buy, so that I can test my meters, scopes, etc ? I don't have any decade boxes or anything, nor any precision voltage/current references.And good kits on ebay for this stuff ?

author: malagas_on_fire
author_rank: Frequent Contributor
timestamp: August 15, 2018, 11:34:02 pm
content: HiTry this for voltage / resistor module if 6½ digit is enough for you're applications:https://www.ebay.com/itm/AD584JH-4-Channel-2-5v-7-5v-5v-10v-High-Precision-Voltage-Reference-Module-/253744941455?roken=cUgayN&soutkn=z4SrlG
Need some SMD LED recommendations for lighting up area. - Page 1
Forum section: electronics / beginners

author: Jackster
author_rank: Frequent Contributor
timestamp: June 25, 2017, 12:37:17 am
content: Need to light up my CNC workspace. Looking for recommendations on some low cost, bright daylight SMD LEDs.(The small ones that are no more than 6x6mm, ~0.5w)There are so many of them from all sorts of brands.I know Cree are really good but $$$, OSRAM are okay though I am sure Mike will say otherwise :pSo yea, what are you guys using?ThanksJack,

author: floobydust
author_rank: Super Contributor
timestamp: June 25, 2017, 07:35:11 am
content: I suggest getting some 5050 LED SMD strip lighting off eBay, waterproof if you have coolant spray to worry about. They are 5x5mm parts.Buying Cree LED's from Digikey or Mouser is expensive, and then you have to reinvent the light bulb getting a PCB made with heatsinking etc. The XP-LED's are best with Mcore (aluminum) PCB, but tricky to solder with hot air.The chinese 3W bead LED's on eBay are just as bright and you can buy them pre-mounted on aluminum PCB's so you just need to add a PSU and heatsink.It maybe easier to just buy an LED bulb from the hardware store.
Need suggestion for an audio recorder for this device.  - Page 1
Forum section: electronics / beginners

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 15, 2022, 01:10:00 pm
content: This cam switch chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/viewer.html?pdfurl=https%3A%2F%2Ffiles.pepperl-fuchs.com%2Fselector_files%2Fnavi%2FproductInfo%2Fdoct%2Ftdoct0123__eng.pdf&clen=5904935&chunk=trueis designed to save and load its settings via a cassette recorder. What is the best choice for a replacement recorder for this.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2022, 01:25:29 pm
content: Please post a functional URL, or at least the full name and model number of the item.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 15, 2022, 01:41:54 pm
content: the unit is the pepperl fuchs fc-21-v cam switch.I will try to attach the pdf in the next post.

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 15, 2022, 01:44:08 pm
content: I can't seem to either attach the pdf or provide a link to it.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2022, 01:56:53 pm
content: It’s almost certainly equivalent to what a Commodore 64, BBC Micro, etc pull have used. I have zero experience with cassette based home computers, so I can’t make any recommendations, but maybe see what people use for those now. The only issue I can think of at all is whether the audio output from the machine to the recorder is mike-level or line-level.

author: tooki
author_rank: Super Contributor
timestamp: January 15, 2022, 01:58:32 pm
content: Quote from: BeBuLamar on January 15, 2022, 01:44:08 pmhttps://files.pepperl-fuchs.com/selector_files/navi/productInfo/doct/tdoct0123__eng.pdf

author: BeBuLamar
author_rank: Super Contributor
timestamp: January 15, 2022, 02:04:39 pm
content: In the manual it indicates to use the mic level input but I made measurement and test recording it's pretty much line level. I have used a real cassette recorder, a laptop with sound card, the old Iphone with 3.5mm phone for mic and headphones. They all works but I need to find something that can easily be used by inexperienced user.Handheld digital recorder works to certain extend but I run in to a number of problem.1. The interface of these devices is kind of difficult to maneuver. I need to set the recording level manually and fixed. Most of those default to auto.2. It's relatively difficult to name and locate tracks for different machines.3. The input and output are 2 channel stereo. I need to make up cable to operate them in 1 channel mono.4. The output seems a little low and the machine won't read correctly with low input.
Need the name of this type of connector - Page 1
Forum section: electronics / beginners

author: sebth
author_rank: Contributor
timestamp: September 01, 2016, 11:14:00 pm
content: Can someone tell my what is the name of the white connector on the cable in this image I included as attachment.Is there any way to find that kind of information online. I tried to search for "flex cable connectors" and similar terms but I could not find it.Thank you

author: amitchell
author_rank: Regular Contributor
timestamp: September 01, 2016, 11:56:13 pm
content: LVDS FFClike thishttp://www.snynelec.com/web/products%201.0ph%20lvds%20ffc%20cable-en.htm

author: sebth
author_rank: Contributor
timestamp: September 01, 2016, 11:59:49 pm
content: Thank you !
Need Tips: First Interview for Charging Infrastructure Role - Page 1
Forum section: electronics / beginners

author: Xenon_K
author_rank: Contributor
timestamp: May 08, 2025, 07:17:52 am
content: Hello everyone,I have my first job interview next week for a working student position at a large energy company. The role focuses on charging infrastructure at substations.Does anyone have any advice on how I should approach the interview? I’m also unsure what exactly the job description might involve and what tasks I can expect. Which skills should I highlight in particular?Since this is my first interview for such a position, I really have no idea what to expect. I would greatly appreciate any tips or insights!Thanks in advance and best regards!

author: Halcyon
author_rank: Unknown
timestamp: May 08, 2025, 07:20:23 am
content: Duplicate post:https://www.eevblog.com/forum/jobs/need-tips-first-interview-for-charging-infrastructure-role/
Need to buy BP2309 Offline PFC'd Buck LED driver - Page 1
Forum section: electronics / beginners

author: ocset
author_rank: Super Contributor
timestamp: January 04, 2020, 01:55:13 am
content: HiWe wish to buy the BP2309 LED driverhttps://datasheetspdf.com/parts/BP2309.pdf?id=1022012But we cant find it on digikey Mouser etc.How do we buy these in 1000's?There is no western equivalent.Even findchips.com dont have a price for it.Its also on BigClive

author: jhpadjustable
author_rank: Frequent Contributor
timestamp: January 04, 2020, 05:27:35 am
content: Bright Power's product pagedoesn't seem to mention it. Maybe it's no longer an active product and you'll need to consider a replacement.

author: ocset
author_rank: Super Contributor
timestamp: January 04, 2020, 09:06:21 pm
content: Thanks, interestingly, 17:01 of the above video shows the MOV being placed downstream of the LC input filter. The MOV has a approx 100n film capacitor across it...thus the MOV will quench the LC ring at power up and this will dramatically reduce its life...(theres no big 'lytic to quench it as its PFC'd) .....the conveniently low 160mA input fuse will blow.This seems like a way of getting the tube to fail early in its life wouldnt you say?.....so customers then just go and buy another...more profit.That MOV should be a TVS...the MOV should actually be right at the front end.