hybridfree/eevblog-posts huggingface dataset:
A circuit connected to a nobreak disconected from main is a floating circuit? - Page 1
Forum section: electronics / beginners

author: Airton
author_rank: Newbie
timestamp: September 04, 2022, 08:08:14 pm
content: I was watching this video about scope safety and begin to wonder if someone wants to probe a main earth safely:Would be pratical and cheaper to connect the system that you want to probe in a nobreak disconected from the main (using the batery) instead of buying one of this active probes?Video:

author: Ian.M
author_rank: Super Contributor
timestamp: September 04, 2022, 08:26:50 pm
content: *NEVER* float a scope not inherently designed for floating use!Engineers have died doing that!See:https://www.eevblog.com/forum/testgear/ground-of-oscilloscope-always-connected-to-earth/If on the other hand you propose to float the D.U.T, (device under test), yes, that's possible and usually safe for the scope, but remember that as soon as you connect the scope the isolation transformer's output becomes ground referenced, so the whole primary side of the DUT's PSU becomes a mains live safety hazard zone again.

author: Terry Bites
author_rank: Super Contributor
timestamp: September 05, 2022, 10:11:16 am
content: If you want to see whats going down the earth wire use a current transformer.
A diode!  Spics - Page 1
Forum section: electronics / beginners

author: Aows
author_rank: Newbie
timestamp: April 21, 2025, 08:13:57 am
content: Hi everyone.I think it's an easy question.I have a diode I just wanna know it's spics.It's near a type-C charging port.Here is it's pics. The one with a hole on it.Laptop is an asus c434t. Turned off suddenly and it's dead now. Doesn't charge and doesn't turn on.It says in the back of the laptop it requires 15v/3A.I am a noob by the way, but I can replace that diode.Thanks

author: bostonman
author_rank: Super Contributor
timestamp: April 21, 2025, 01:06:13 pm
content: How do you know it's a diode?If it's near the charging port, it may be a TVS diode.Also, I think you mean "specs" as in specifications.

author: Aows
author_rank: Newbie
timestamp: April 21, 2025, 03:01:28 pm
content: Hi sir.It's look like a diode and I searched in the web for that (KF) marking on it. I've got that (Picture attached) .It's looks the same and there is a 15V mentioned. Like I am gathering evidence. i don't know if it's a diode or not, that's why I am here asking.And yes specs = specifications.Thanks alot

author: Terry Bites
author_rank: Super Contributor
timestamp: April 25, 2025, 12:26:37 pm
content: https://smd.yooneed.one/Search for KF et voilà!Transient voltage supressorVrwm=6.0V, Vbr=6.67..8.45V, 52.6A, 600W(1ms)

author: tooki
author_rank: Super Contributor
timestamp: April 25, 2025, 06:06:38 pm
content: Quote from: Aows on April 21, 2025, 03:01:28 pmWe all know what “specs” means. But you wrote “spics”, which is an offensive word for a certain ethnicity. That’s what he was trying to tell you…

author: gamalot
author_rank: Super Contributor
timestamp: April 25, 2025, 06:38:25 pm
content: If it is a SOD523 package (approximately 1.2mm*0.8mm body size), then it is likely a MM5Z7V5B Zener:https://www.alldatasheet.net/datasheet-pdf/view-marking/1284812/SKTECHNOLGY/MM5Z7V5B.html

author: Aows
author_rank: Newbie
timestamp: April 27, 2025, 02:23:29 pm
content: I im really sorry I didn't mean it that way. Forgive me.

author: Aows
author_rank: Newbie
timestamp: April 27, 2025, 02:37:42 pm
content: Thanks alot @gamalot and @Terry Bites. Gonna check about that once i got it back from a professional (he call himself). He just replaced the Type-C port and it didn't work then he said it could be the processor.
A doubt on my single transistor flyback driver - Page 1
Forum section: electronics / beginners

author: pranavAppu
author_rank: Newbie
timestamp: March 09, 2017, 04:58:14 am
content: I've been teying to build a simple flyback driver with a 2N3055 transistor using an input of a UPS battery but my transistor is failing. Now I've bought a 2N3055 HV2 transistor. Will it withstand?This is my very first project..*written by :PranavAppu/

author: Benta
author_rank: Super Contributor
timestamp: March 09, 2017, 10:07:34 am
content: You already asked about this design in another thread, and got a load of answers. Didn't you like them?

author: SingedFingers
author_rank: Frequent Contributor
timestamp: March 09, 2017, 10:21:58 am
content: Less turns on the base coil. 2-3 turns max or you'll break the transistor down instantly. Also stick a big 15W 10 ohm resistor in series with the supply until you get it working or it'll blow everything out in half a second flat. Also heatsink that transistor. I've built something pretty much identical that worked in the dark ages. They're not pretty but they work.Also don't play with high voltages until you know what you are doing. You'll kill yourself or someone else.Better design here that uses two primary coils and a feedback coil:http://ludens.cl/Electron/scope/scope.png
a doubt with the oscilloscope probes - Page 1
Forum section: electronics / beginners

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: May 13, 2018, 04:08:40 pm
content: a doubt with the oscilloscope probes, if set X1, and for example 12 volts is applied, to oscilloscope 12 volt arrives, until everything is correct, but if you set them X10, it does not reach 1.2 volts in the rigol ds1054z that Example use I get 6.2volts, then does not attenuate X10, but attenuates by X2?in spanishuna duda con las sondas de osciloscopio, si se las setea X1, y por ejemplo se aplica 12 volts, a osciloscopio llegan 12 volt, hasta todo es correcto, pero si las seteo X10, no llega 1,2 volts en el rigol ds1054z que uso de ejemplo me llega 6,2volts, entonces no atenua X10, sino que atenua por X2?

author: Dave
author_rank: Super Contributor
timestamp: May 13, 2018, 05:16:47 pm
content: Are you using an oscilloscope to measure what 'arrives', or are you using a multimeter that you poke into the BNC end of the probe?When you switch your probe over to x10, what you're doing is adding a 9M resistor in series. If the device you're measuring the voltage with doesn't have 1M input impedance, you're not going to get 1/10 on the output.The reason I'm guessing you're measuring with a multimeter is that their input impedance is usually 10M, so adding 9M in series would give you 10/19 of the input voltage, or 6.3V with a 12V input.

author: Adrian_Arg.
author_rank: Frequent Contributor
timestamp: May 13, 2018, 06:54:48 pm
content: ok
A Few PulseView Questions (Moved to Microcontrollers Forum) - Page 1
Forum section: electronics / beginners

author: Electro Fan
author_rank: Super Contributor
timestamp: April 13, 2020, 11:44:25 pm
content: Post was moved to here:https://www.eevblog.com/forum/microcontrollers/sigrok-pulseview-questionscommentsdiscussion/new/#new
A few Questions from a New Member - Page 1
Forum section: electronics / beginners

author: GrievousAngel
author_rank: Contributor
timestamp: February 19, 2021, 12:05:45 am
content: Hello . . .New kid on the block, right . . . Anyways, I'm GrievousAngel > hoping for good weather with happy trails ahead! (Bang)Q1> Any suggestions for an electronics grade adhesive that sets within a minute or so, fills gaps, strong but can be removed if needed. Not sensitive to contact cleaner or iso-alcohol, plays well with temperatures typically found on PCB, heat sinks, etc. Main use for me would be structural bonding like stabilizing larger caps, attaching diodes to power transistors, mounting a LED in a panel hole, etc.Like most of us, I've used different adhesive types. I'm looking a better electronic-grade thick bodied adhesive (I haven't tried yet). Suggestions?Q2> Also, any well-kept secrets of an adhesive suitable for re-attaching PCB copper traces? I've tried some 'Super-Glue' types with fair to zero results. Anyone replacing copper traces with good results?Q3> Your favorite 'tamper-proof' putty/glue to lockdown trim pots, screws/nuts, threaded adjustable mechanisms, etc?[Off-topic]If interested, I'm going to post a thread about a DIY Active Differential Probe (centered around a TI Instrument grade opamp) I built to improve the 'useful' measurability of an analog audio signal in real world noisy situations. I will use it with my PICO 4262 Analog (Purpose-built) O'Scope/Spectrum-Analyser and/or a Rigol DM3058E 5-1/2 DMM. Being new, I think I noticed a Test Gear Measurement Forum somewhere, so I'll post it there in a day or two.Excited to be here with y'all to share projects and technologies. Thanks for checking-out my post.GrievousAngel (aka Billy)

author: joeqsmith
author_rank: Super Contributor
timestamp: February 19, 2021, 01:14:14 am
content: Black Max? Tak Pak? Both require an accelerator. Keep away from them with your soldering iron.
A few questions on assembling an O2 amplifier - Page 1
Forum section: electronics / beginners

author: l3gi0n
author_rank: Regular Contributor
timestamp: October 15, 2021, 08:07:39 pm
content: I have a few questions about the polarity of different components so please confirm that I am correct:(1) Ceramic capacitors are non-polar.(2) Film capacitors are non-polar.(3) Resistors are non-polar.(4) Electrolytic caps are polar.(5) Diodes are polar.(6) Transistors, MOSFETs, and Voltage Regulators are polar.A question:In the following PCB, Q1, Q2 are MOSFETs and U5, U6 are Voltage Regulators :How do I solder Q1, Q2, U5 and U6 ? The metal side of the MOSFETs/VRs should be facing the thick line on the PCB ? please explain...

author: Manul
author_rank: Super Contributor
timestamp: October 15, 2021, 08:23:17 pm
content: Yes, generally you are correct on all 1,2,3,4,5,6 (no need to talk about exceptions here).For packages like TO-220 and similar, thick line should indicate where back of package should face. Back is the flat side where you can mount a heatsink. If in doubt, look schematic and compare with the pinout of a part.

author: Benta
author_rank: Super Contributor
timestamp: October 15, 2021, 08:24:04 pm
content: 100% on all points.

author: magic
author_rank: Super Contributor
timestamp: October 15, 2021, 08:46:52 pm
content: Pictures of assembled boards, build instructions, etc...http://nwavguy.blogspot.com/2011/08/o2-summary.htmlhttp://nwavguy.blogspot.com/2011/08/o2-details.htmlA few words:Try to get the exact MOSFETs, don't substitute. The layout is terrible and some MOSFETs end up oscillating hereThe recommended opamps have phase reversal. Lose the negative rail and the output goes to the positive. The "power management" subcircuit is critical and it has to work right (see above).DIP ICs are a PITA to desolder. I like having them in sockets, just in case.

author: Terry Bites
author_rank: Super Contributor
timestamp: October 17, 2021, 02:20:01 pm
content: Save yourself from more heartache by soldering the smd parts first.
A good book to learn about advanced electronics and arduino - Page 1
Forum section: electronics / beginners

author: skillz21
author_rank: Frequent Contributor
timestamp: September 27, 2017, 03:42:00 am
content: I want to learn aboit electronics, right now I have the rudimentary knowledge, enough to make basic circuits and things (with only passive components and arduino) but I would like to extend that further. Can someone recommend a book for me learn about electronics and circuits and how to build circuits and so on? Also, a book to learn about how to properly code with Arduino, as I am not the best at coding.Thanks!Sent from my @#$%^^$# using Tapatalk

author: rstofer
author_rank: Super Contributor
timestamp: September 27, 2017, 05:23:27 pm
content: There are 1,650,000 hits at Google for "Arduino Programming" and there are dozens of books at Amazon. Some of the books are free for Kindle Unlimited and cheap for regular Kindle. I don't prefer Kindle books for textbooks as it isn't always easy to get to section 5.1.Books will come at the Arduino from different directions depending on what the author is doing. Pick a book that seems to line up with what you want to do (Audio, Robotics, Displays, <whatever>). Or refine the Google search. Or check for used books on Alibris.comhttps://startingelectronics.org/beginners/start-electronics-now/"Advanced" electronics, as EEs would think of it, might be a little over the top but if you decide on a project, there are articles all over the Internet.See if there is anything at Adafruit or Sparkfun that grabs your attention.There is always the Arduino web site:https://www.arduino.cc/

author: cepwin
author_rank: Unknown
timestamp: September 27, 2017, 10:20:05 pm
content: I found an interesting arduiino course on udemy for $11 (Arduino Fundamentals by hackster.io...it was on sale....always best to buy their classes on sale)...the instructor (who you may have seen in sparkfun videos) very clearly leads you step by step from simple stuff up to much more advanced projects. Also most of it can be done in tinkercad (an online design website by autocad). This is working for me as I prefer to learn this way (watch and do) verses a book.
A Good Book to Learn AVR Programming in Assembly and C  - Page 1
Forum section: electronics / beginners

author: bharatcs
author_rank: Contributor
timestamp: February 22, 2017, 06:23:01 pm
content: HelloCan you guys recommend me book to learn avr programming in assembly and c ?Is "AVR Microcontroller and Embedded Systems: Using Assembly and C "by Mazidi / Naimi / Naimi a good book?

author: JoeO
author_rank: Frequent Contributor
timestamp: February 22, 2017, 07:24:43 pm
content: https://www.amazon.com/Programming-Interfacing-ATMELs-Thomas-Grace/dp/1305509994/ref=sr_1_1?ie=UTF8&qid=1487791430&sr=8-1&keywords=thomas+grace+avr

author: jakeisprobably
author_rank: Regular Contributor
timestamp: February 22, 2017, 10:08:28 pm
content: I might suggest you look into using Fourth on AVR. I don't have experience with it myself, but I've watched quite a few tutorials and played around with arduino's on a few occasions. There's this newer guy on YouTube doing electronics tutorials using Fourth and it looks interesting.https://youtu.be/EnCyPzSsloo. All the books I have pretty much require you to do a bunch of boring projects, but that's the typical junk you find at the local bookstores.I would NOT recommend:Arduino Workshop (Boxall)Arduino Robot Bonanza (McComb)These are what the local Barns and Noble had in stock at one point and I bought.Programming Arduino Getting Started With Sketches (Monk)That's a very small reference that is more direct, but it is very very basic.From what I've seen, Adafruit/Sparkfun/Arduino Forum/YT have a reference for almost anything you could ever need IMHO.

author: hugo
author_rank: Regular Contributor
timestamp: February 23, 2017, 12:14:41 am
content: This is also a good book :https://www.amazon.ca/AVR-Programming-Learning-Software-Hardware/dp/1449355781
A good recording device - please suggest - Page 1
Forum section: electronics / beginners

author: Jane
author_rank: Frequent Contributor
timestamp: July 12, 2023, 07:42:32 pm
content: What recording device do you use when you repair various equipment?I think having disassembly video may come in handy when you assemble the equipment.

author: audiotubes
author_rank: Regular Contributor
timestamp: July 12, 2023, 09:35:40 pm
content: I was thinking about this recently.Gopro cameras have good stability and tons of mounts and other accessories. The resolution is not very good compared to a phone but they may have some advantages.Eventually I'll try my Gopro for this.

author: EPAIII
author_rank: Super Contributor
timestamp: July 14, 2023, 09:40:09 am
content: An old cell phone.

author: AndyC_772
author_rank: Super Contributor
timestamp: July 14, 2023, 10:14:18 am
content: I don't use video, but do find good still photos invaluable.For simply documenting what goes where, I use an old Canon IXUS 800IS. It's light and compact, has a very quick and easy to use macro feature, and since the photos are just 6MP they're a handy size - plenty detailed enough for documentation but not a huge waste of storage.To document specific findings for customers (eg. cracked solder joints, mechanical damage to components) then I go to the other extreme and break out the big guns. Canon 5DSR (50MP) plus a 100mm f/2.8 macro lens, or sometimes the MP-E 65mm, and some carefully positioned fixed lights or dedicated Godox macro flashes.Yes, photography is one of my expensive hobbies
A Ic that acts as a Controlled buffer? - Page 1
Forum section: electronics / beginners

author: ThePeoplesLab
author_rank: Newbie
timestamp: October 20, 2018, 05:35:52 am
content: Hi All I'm looking for a Ic that can take in a single 5v input to allow ~2 (or more) separate data lines to connect. Is there an Ic for this I have yet to find one,if not does anyone have a solution for me? I'm looking to switch a rx and tx line from a chip to 2 different sources with only one switch per source, (ie, Switch one connects them to the Usb converter chip, Switch two connects it to a different chip) Thank you all!! - Tavian

author: tautech
author_rank: Super Contributor
timestamp: October 20, 2018, 06:39:53 am
content: CMOS Bilateral switch:http://www.ti.com/lit/ds/symlink/cd4066b-q1.pdf

author: ThePeoplesLab
author_rank: Newbie
timestamp: October 20, 2018, 06:56:06 am
content: That works Perfectly!!! Thank you!
A job in solar energy - Page 1
Forum section: electronics / beginners

author: Blueeyes
author_rank: Newbie
timestamp: August 16, 2019, 12:21:23 pm
content: Hi I'm new to the forum.I am from Romania and I entered a faculty of electrical energy from me in the country.In the future I would like to work in the field of solar energy, but I have some questions about field.1.) I would like to become a specialist in the maintenance of a photovoltaic park.2.) How does a photovoltaic panel work, could you give me some materials or videous with that? (I would like with videous where a person explains the physics and mathematics of the photovoltaic panel).3.) Do you have to have deep mathematical knowledge for this or not?Thank you and I'm waiting for answers.

author: EEVblog
author_rank: Unknown
timestamp: August 16, 2019, 12:25:28 pm
content: Quote from: Blueeyes on August 16, 2019, 12:21:23 pmNot for maintenance or install, no.Not even for designing large scale systems, basic engineering math would be all that's needed.Start with:https://www.youtube.com/results?search_query=solar+panel+construction

author: atmfjstc
author_rank: Regular Contributor
timestamp: August 17, 2019, 02:23:00 pm
content: Just put the panels on rooftops and not on roadways, and you should be fine

author: bdunham7
author_rank: Super Contributor
timestamp: August 19, 2019, 05:14:06 pm
content: For design, installation and maintenance of actual solar installations you don't need much physics, all though it is nice to know a few things--perhaps to understand issues like why solar cells become less efficient when hot. However, what you actually need to know are:1) Mechanical engineering and building codes. The hardest thing about solar installations is getting them approved and making sure they don't fall down or blow away--or get run over by trucks.2) Basic electrical theory and electrical building codes at the level of a journeyman (experienced) electrician or so. While the circuits themselves are dead simple, the safety code requirements can be extensive.The theoretical aspects are all taken care of by the product manufacturers, you just have to be able to understand their datasheets and installation requirements.
A Layout potential problem - Page 1
Forum section: electronics / beginners

author: Freshman
author_rank: Regular Contributor
timestamp: May 05, 2025, 11:19:39 am
content: Red marked trace is a 5V power rail on the bottom layer of PCB. On both sides of this 5V, is ground. The total board is 4 layers with the IC mounted on Top and having ground. L2 is ground. L3 is power. L4 is the one shown.The ground on either side of the 5V on the L4, will it cause ground bounce issues? Since the ground has to go over the traces and move to the other side of the ground of the IC?

author: mtwieg
author_rank: Frequent Contributor
timestamp: May 05, 2025, 11:35:55 am
content: If you have a solid ground plane on an inner layer, then there shouldn't be a problem. For components on the top layer (the large IC) the inner GND plane will be a preferable return path anyways.

author: Jeroen3
author_rank: Super Contributor
timestamp: May 05, 2025, 11:36:51 am
content: Is there a solid ground layer on any of the internal layers?

author: Freshman
author_rank: Regular Contributor
timestamp: May 05, 2025, 12:47:32 pm
content: OK sure thank you. There's solid ground plane on L2.

author: Jeroen3
author_rank: Super Contributor
timestamp: May 05, 2025, 02:27:46 pm
content: Then the track won't cut the plane.You may not need to fill the top/bottom with ground polygon if you have continuous ground planes on the inner layers.It looks like you are using thick traces for power distribution, is the other inner layer not available for this?You could achieve better impedance using the planes.If there is no inner ground plane the risk of cutting through like this will be that currents may need to go around this trace for their return path.Around an MCU there may be high frequencies (fast edges, clocks) that may cause trouble during radiated emissions testing.When laying out a board, try to imaging any signals going from a chip to somewhere, also having a reverse signal that wants to go back through ground as near as possible to the signal trace.I would recommend the videos from Robert Feranec on youtube:https://www.youtube.com/robertferanecHe handles these scenarios often and has interviews with experts on the subject matter.
A LiFePO4 battery emulator circuit to allow a multi-cell charger to do 1 cell? - Page 1
Forum section: electronics / beginners

author: e100
author_rank: Frequent Contributor
timestamp: September 29, 2023, 09:21:07 am
content: Suppose you have a charger that is designed for charging 4 cells in series, but you only have one cell that needs charging.Is there a gadget that can be placed in the vacant positions to make the charger think there are actually 4 cells present?(I realize the dummy cells will be dissipating a fair amount of power)

author: Vovk_Z
author_rank: Super Contributor
timestamp: September 29, 2023, 09:46:59 am
content: There possibly can be such a device (I haven't heard about it). But it seem to me it is much simpler and cheaper to find a charger which can charge 1 cell.

author: BeBuLamar
author_rank: Super Contributor
timestamp: September 29, 2023, 05:22:23 pm
content: I think it would be easier just to build a 1 cell charger or you can simply charge 4 cells and use the cells one at a time.

author: gf
author_rank: Super Contributor
timestamp: October 01, 2023, 07:52:49 am
content: Charging indiviual LiFePo4 cells with potentially arbitrary SOC in series is not a good idea. If you try to get the cell with the lowest SOC full, you overcharge the others.OTOH, the cells of a series pack are charged and discharged together to keep SOC imbalance small, and the pack is usually also equipped with a BMS to re-balance these small differences.

author: MrAl
author_rank: Super Contributor
timestamp: October 01, 2023, 10:37:16 am
content: Quote from: e100 on September 29, 2023, 09:21:07 amI would think this is possible but if you have to do this often it will waste a lot of energy. It would take almost four times as much energy to charge just one cell than if you had a 1 cell charger do it.In this day and age we try to save energy not waste it.The dummy cells would have to be like diodes in series but the voltage would have to be more constant, and depending on the method used by the charger it may or may not be able to determine the end of charge termination condition. In other words, you'd have to be very careful or some bad things could happen.
A Lithium Battery Charger with Load Sharing - Page 1
Forum section: electronics / beginners

author: chota.sanjiv
author_rank: Contributor
timestamp: June 11, 2016, 07:55:46 pm
content: Hi Guys,I was referring the following circuit for battery charger with load sharing ie. the circuit will get powered via main power and when its not there it will switch to battery immediately, in the circuit I cannot understand the R2 pull down ,won't it cause extra power consumption for my circuit. ?http://blog.zakkemble.co.uk/wp-content/uploads/2013/05/MCP73831_loadshare.pngregards,Sanjeev

author: ConKbot
author_rank: Super Contributor
timestamp: June 11, 2016, 08:06:52 pm
content: Without r2, what happens when the charger is removed? The voltage on the VDD net will be floating at a point where the diode leakage and current used by the charger ic are equal. The mosfet may not be turned on fully or at all, adding a diode drop between the battery and the load. With the pulldown, VDD goes to ground, the mosfet his turned on fully, and the load gets full battery voltage.

author: Signal32
author_rank: Frequent Contributor
timestamp: June 13, 2016, 08:13:01 pm
content: As ConKbot mentioned, R2 is required so that the circuit will function correctly. And yes, you are correct, it will add extra load to your circuit, though a very small one (0.05mA).
A little help needed designing a power button circuit for my PC - Page 1
Forum section: electronics / beginners

author: Marmotta
author_rank: Contributor
timestamp: December 02, 2016, 12:00:20 am
content: I'm currently planning a HTPC using an Xbox One case and am planning to keep as many original features as possible, including the Xbox One power supply and front power/eject/sync assembly.I have built the touch sensitive momentary/latching circuit for the power button, but I need some advice on the startup/shutdown circuitry.The Xbox One PSU outputs 12V, so I'm connecting the motherboard using a PicoPSU and will wire the 12V directly to the graphics card. Powering on is not an issue - pressing the power button will latch together the 5V standby and Sense outputs on the PSU and switch on the 12V; I will connect the motherboard power pins either with a slight timed delay directly to the power button's momentary circuit or to the 12V source via a relay.However, I'm not sure about how to go about shutting down the system - I need to create enough of a delay between pressing the power button and the 12V cutting out for the PC to safely power down. I think maybe I could do something to affect the behaviour of the button depending on whether 12V is detected (i.e. the console is clearly in a powered on state) or not, but not sure how, maybe with a CMOS analog switch?Thanks in advance for any help.

author: wraper
author_rank: Unknown
timestamp: December 02, 2016, 12:18:54 am
content: Quote from: Marmotta on December 02, 2016, 12:00:20 amWhy don't you just do the right thing and use the PS-ON signal from the motherboard? No fixed delay (unless completely ridiculous) will predict when it is safe to shut down the power, as OS (guess windows) may decide installing updates or something else. Also, if power other than 5VSB is present before starting the motherboard, it may happen to glitch in various strange ways.

author: Marmotta
author_rank: Contributor
timestamp: December 02, 2016, 11:46:21 am
content: I was thinking about this and it's slightly complicated by the fact that the PicoPSU's only intake is 12V and I really wanted to avoid having to solder to the PSU or motherboard at all. What I might do though is design a circuit that will unlatch the Xbox One PSU's SENSE when a low signal is detected from the motherboard's 5V USB port connections, as it would mean the motherboard had safely gone into standby.

author: sparx
author_rank: Contributor
timestamp: December 04, 2016, 08:01:45 pm
content: Why not find the "Power on" led - on the motherboard header and use that as a "power on" sense? It might go wacky in standby, but you could maybe sort that out also.5V usb on all of my computers here remains on, even in complete shutdown.
a little help - OBD specification - Page 1
Forum section: electronics / beginners

author: r
author_rank: Contributor
timestamp: March 15, 2014, 12:51:35 pm
content: i am doing a project for my level 3 course and need to get my hands on some stuff .if anyone could help me out I am doing a project on using the RASPBERRY PI and OBD 1, I am after the data sheets/technical spec for OBD 1 1997 nissan micra hope u lot can help as i have a limited amount of time left to get this imformation i am trying to use a raspberry pi to read the binary data coming out the OBD port.

author: Rerouter
author_rank: Super Contributor
timestamp: March 15, 2014, 01:11:40 pm
content: Here are the trouble codes for a toyota avensis (different vehicle but may overlap)OBD1 Codes 1 Normal Condition. 2 Air Flow Meter signal. 3 Ignition signal. 4 Engine Coolant Temperature Sensor signal. 5 Oxygen Sensor. 6 RPM signal (Crank Angle Pulse). 7 Throttle Position Sensor signal. 8 Intake Air Temperature Sensor signal. 9 Vehicle Speed Sensor signal. 10 Starter signal. 11 Switch signal. 11 ECU/ECM. 12 Knock Control Sensor signal. 12 RPM signal. 13 Knock Control CPU (ECM). 13 RPM signal. 14 Turbocharger Pressure. 14 Ignition signal. 21 Oxygen Sensor. 22 Engine Coolant Temperature Sensor signal. 23 Intake Air Temperature Sensor signal. 24 Intake Air Temperature Sensor signal. 25 Air-Fuel Ratio Lean. 26 Air-Fuel Ratio Rich. 27 Sub Oxygen Sensor signal. 28 No. 2 Oxygen Sensor signal. 31 Air Flow Meter signal (Vacuum Sensor signal). 32 Air Flow Meter signal. 34 Turbocharger Pressure signal. 35 Turbocharger Pressure Sensor signal. 35 HAC Sensor signal. 41 Throttle Position Sensor signal. 42 Vehicle Speed Sensor signal. 43 Starter signal. 51 Switch signal. 52 Knock Sensor signal. 53 Knock Sensor signal. 54 Inter-cooler ECM signal. 71 EGR System. 72 Fuel Cut Solenoid signal. 78 Fuel Pump Control signal. 81 TCM Communication. 83 TCM Communication. 84 TCM Communication. 85 TCM Communication.As for how to decode it, i've not been able to turn up anything more than it being a (early) variant on OBD2here is something else that may helphttp://www.eobd2.eu/data/3111eu_Manual.pdf(it lists the 5 types of protocols commonly used which may help you,

author: Neverther
author_rank: Regular Contributor
timestamp: March 15, 2014, 02:31:03 pm
content: Reading binary data might be a fun trick, but have you considered using something like ELM327 to handle the protocol (if the one used by the car is included, page 25 on datasheet)?If you still dont know howto handle the protocol, use one of those USB ELM327 bricks and sniff the serial data when you connect it using some diagnostics software.Protocol might be ISO 9141-2, ISO/DIS 14230-4 (KWP2000) which is supported by elm.

author: r
author_rank: Contributor
timestamp: March 15, 2014, 05:09:23 pm
content: Quote from: Neverther on March 15, 2014, 02:31:03 pmhave tried one off the modules and had no luck but looking at the data sheet my get my self the chip on it own to see if i can get it to work
A load off my mnd - Page 1
Forum section: electronics / beginners

author: PerranOak
author_rank: Frequent Contributor
timestamp: January 25, 2019, 03:14:50 pm
content: I'd like to make an electronic load. Something simple with modest parameters, say, up to 1A and 25V or so.Any recommendations for a nice circuit that you may have seen?Thanks.

author: JackJones
author_rank: Regular Contributor
timestamp: January 25, 2019, 03:45:27 pm
content: There is the eevblog DC load, about as simple as you can get:If you want something a little bit fancier, this Scullcom DC load is pretty good, highly recommend watching the videos.

author: PerranOak
author_rank: Frequent Contributor
timestamp: January 26, 2019, 02:56:51 pm
content: Brilliant! Cheers and thank you.

author: JackJones
author_rank: Regular Contributor
timestamp: January 26, 2019, 03:17:25 pm
content: I have built both of those DC loads, in fact I think the eevblog version was one of my first projects. I think it might have been oscillating though, I remember hearing a buzzing sound coming from it at higher currents. Next time I powered it up it was dead. I didn't have a scope back then so couldn't check. Might make sense to put a series resistor to the gate and/or a snubber from the opamp output to the opamp negative input if you're going for the simpler design.I also built the Scullcom version with minor modifications, like some different component choices and used a micro for it. I'm not a big fan of using Arduinos permanently in projects, it's much more professional to just use a micro. Nothing wrong with it though.I'd suggest watching the whole series of the Scullcom videos if you go that route, because he does add quite a bit of functionality to the design over the videos.

author: MarkF
author_rank: Super Contributor
timestamp: January 26, 2019, 04:09:55 pm
content: Here is mine. For low currents you can get away without a fan.Edit: Updated circuit

author: rdl
author_rank: Super Contributor
timestamp: January 26, 2019, 04:23:16 pm
content: The EEVblog version is worth looking at as a start. It's pretty simple and easy to build, but it usually oscillates. That's easily fixed as long as you have an oscilloscope to see what it's doing.

author: PerranOak
author_rank: Frequent Contributor
timestamp: January 29, 2019, 02:52:11 pm
content: "Loads" to look at, thanks.
A logic analyzer that can decode USB 2 High Speed (480MBits/s) protocols - Page 1
Forum section: electronics / beginners

author: JustAnotherGuy999
author_rank: Contributor
timestamp: March 06, 2016, 01:45:34 pm
content: if it can decode Ethernet protocol too, that would be nice.

author: Simon
author_rank: Unknown
timestamp: March 06, 2016, 01:51:33 pm
content: just don't get a PC based one on USB2

author: wraper
author_rank: Unknown
timestamp: March 06, 2016, 01:52:39 pm
content: Logic analyzer is a wrong tool for this. You need specialized USB protocol analyzer for the task. I'm sure there are universal logic analyzers which can work with USB, but the cost will be insane.

author: tggzzz
author_rank: Super Contributor
timestamp: March 06, 2016, 01:53:29 pm
content: Your first problem will be to ensure signal integrity when you attach a probe to a high speed (i.e. analogue) line.

author: Simon
author_rank: Unknown
timestamp: March 06, 2016, 02:30:21 pm
content: Quote from: tggzzz on March 06, 2016, 01:53:29 pmHis second problem is to stop asking wildly random short questions.

author: tggzzz
author_rank: Super Contributor
timestamp: March 06, 2016, 05:51:47 pm
content: Quote from: Simon on March 06, 2016, 02:30:21 pmYes. And us answering them!Perhaps they'll learn something fromhttps://entertaininghacks.wordpress.com/library-2/good-questions-pique-our-interest-and-dont-waste-our-time-2/but I won't hold my breath.

author: Mechatrommer
author_rank: Super Contributor
timestamp: March 06, 2016, 09:03:22 pm
content: #1) long question, not understandable = -10 ^ 3 marks#2) short question, not understandable = -10 ^ 2 marks#3) long question, understandable = -10 ^ 1 marks#4) short question, understandable = 10 ^ 3 marksthe OP's question is #4... but that just my intellectual interpreting it. this ever growing forum is filled with either question type #1 or #3, majority.

author: Simon
author_rank: Unknown
timestamp: March 06, 2016, 09:06:27 pm
content: This user has posted a lot of one liner questions with no background. In fact the typical pattern of posting of somone wanting to spam the forum. They fill the forum with nonsenical posts that are borderline and then put spam in their signature as it retrospectively updates on all posts. they obviously massively over estimate how long it takes to just delete their account and all of their posts as well. Or he is trying to get his post count up for some competition, another user has alreasy been banned for that, this one is getting close.
A magic smoke incident - Page 1
Forum section: electronics / beginners

author: Lee697
author_rank: Regular Contributor
timestamp: May 18, 2021, 10:37:04 pm
content: Cooking chips in the garage last night.... well, just a toasty ESP32 Thing Plus board and an ATtiny85 appetizer! I've been working on a little wifi board that controls a pair of relays, finally had it all working how I want, and had 3D printed an enclosure. Soldered in some tails for some relay outputs (NC) and an power inlet/switch, quick test before connecting up the relay output sockets, as after that getting to the copper tracks would be a nuisance. Grabbed a charged SLA batt from the bench, hooked up - pop! poof! and up went the magic smoke....I'm unsure what happened.I've checked and double checked the power connections I made, and they seem OK. The two voltage regs on the (now chipless) board are working OK (seemingly). I'm left with the conclusion I must have mixed up the battery terminal polarity (first time in 30yr I think.... it was late last night). Other possibilities, perhaps a short from a stray lead on the bench ( I do check for these), I'm even wondering if one of the live (12V) relay output wires had curled under the board and tickled somewhere fragile?Apart from the two chips (ESP32 and ATtiny85), which are easy to replace, there are a handful of bypass caps (on two linear VRegs) and some low-side switching NPNs. If the VRegs are producing correct voltages should I assume the caps are OK?I'm going to run it back up without the chips and probe the sockets carefully and test the transistors before replacing the chips.... Does anyone have any other advice? (apart from reverse polarity protection diodes! 🙂 )

author: TopGun
author_rank: Contributor
timestamp: May 19, 2021, 06:17:03 am
content: Do you have a schematic of your circuit? Did you have the relay directly hooked up to the digital pins of the AtTiny? A few pics would be good.

author: Lee697
author_rank: Regular Contributor
timestamp: May 19, 2021, 06:43:15 am
content: There are two relays, they are switched from digital pins on the ESP32, through 2N4401's, with flyback diodes. The ATtiny is there to stop the ESP wifi server 'wandering off' as I've noted it can do every few days sometimes, it drives a 2N4401 to ground the ESP's reset pin every 6 hours.I scoured the board today at lunchtime, probed all of the IC sockets, tested the transistors/relays, exchanged the caps, and reinserted some new ICs, and all is back up again.... I'll see if I can draw a schematic tonight....

author: Lee697
author_rank: Regular Contributor
timestamp: May 19, 2021, 12:40:26 pm
content: A bit of block diagram/pseudo-schematic....There are two individually controlled relays, there's also an LED and a voltage divider over an analog input for battery voltage sensing.....
A manual reset thermal cutoff switch - Page 1
Forum section: electronics / beginners

author: wirehead_freenode
author_rank: Contributor
timestamp: September 15, 2020, 12:07:46 am
content: Hello, I have a device I'm planning to make that will get hot after prolonged use. To prevent it from getting too hot, I would like a 80 degree celsius thermal cutoff switch that requires a manual reset. Can someone please find one that is sub-$10 USD? I am not sure if I'm naming it correctly either.Thank you for your consideration.Edit: found solution athttps://www.aliexpress.com/item/32982877641.html?spm=a2g0o.productlist.0.0.672168c0ZU5fed&algo_pvid=e2da7d90-f671-41de-b750-fe7a4b31b0d0&algo_expid=e2da7d90-f671-41de-b750-fe7a4b31b0d0-50&btsid=0bb0624516001296891754952eb366&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

author: Rasterist
author_rank: Contributor
timestamp: September 15, 2020, 04:42:12 am
content: How do you manually reset that?If your device has a microcontroller you could have it monitor any of a number of different kinds of temperature sensors (digital or analog) and take appropriate action when the threshold is crossed.

author: Jwillis
author_rank: Super Contributor
timestamp: September 15, 2020, 08:07:03 am
content: Those particular thermal switches are not designed for repeated use . Like many thermal breakers they weaken quickly with repeated use . They are designed as a saftey device in case of catastrophic failure that would prevent a cool down.I don't know what type of circuit you are making but with proper passive and /or active cooling any circuit or device need not become so hot that a saftey device trips with regular use.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 16, 2020, 09:54:10 am
content: You can remove all the spam from the ali links i.e:https://www.aliexpress.com/item/32982877641.html

author: wirehead_freenode
author_rank: Contributor
timestamp: September 16, 2020, 01:27:55 pm
content: It's a manual reset. A pushbutton resets it.I don't intend for the temp cutoff to trip repeatedly, just maybe once in a blue moon if someone leaves the device on. Like a hairdryer.
A mosfet, a dif comparator, a bridge rectifier, and an inductor walk into a bar. - Page 1
Forum section: electronics / beginners

author: Beamin
author_rank: Super Contributor
timestamp: July 23, 2018, 07:58:02 am
content: A mosfet, a diff. comparator, a bridge rectifier, and an inductor walk into a bar where they talk to a BC557 and a BC547 a big cap and some resistors.What would you call this thing? I don't remember building it. My guess from the fact it has 4 leads two are "AC" and one is cat. and an. that it's a regulator or tiny power supply.Will it mess it up if I put DC to it? How would I know how much voltage it takes? It has no part numbers on the board. Certainly it can't take mains power could it? Why else would you have A/C inputs unless it's supposed to work with a transformer.What does the comparator do? I haven't seen that in a power supply. Is it so it can adjust a range of voltages and still stay at the output? To find voltage do you look at how much this IC can handle then trace out resistor that goes to it?

author: pyroesp
author_rank: Regular Contributor
timestamp: July 23, 2018, 08:51:43 am
content: It's a 1W/3W power LED driver.It's a Velleman kit, 2 sec google search :https://www.velleman.eu/downloads/0/illustrated/illustrated_assembly_manual_k8071_rev1.pdf

author: Beamin
author_rank: Super Contributor
timestamp: July 23, 2018, 02:44:52 pm
content: Quote from: pyroesp on July 23, 2018, 08:51:43 amI looked at their kits and didn't see this one. But I suck at seeing though.
a mosfet question about electronic circuits - Page 1
Forum section: electronics / beginners

author: circuit975
author_rank: Contributor
timestamp: May 13, 2024, 07:48:29 pm
content: I stated my question as a pictureThis is the mosfet channel adjustable circuit example question.When calculating Vgs in this question.We know that Vgs = Vg - VsVg = 1,5 VWe know that Vs = Id.Rsbut I don't know what to do next.the person who helped is really much appreciated thanks

author: Alex Nikitin
author_rank: Super Contributor
timestamp: May 13, 2024, 10:05:08 pm
content: Hi and welcome to the forum!From the look of it, you have got all the right formulae, however you've got the polarity wrong for Vp, as far as I can see.CheersAlex

author: circuit975
author_rank: Contributor
timestamp: May 13, 2024, 10:14:00 pm
content: thank you, but I don't know what is right or wrong, can you analyse it?

author: circuit975
author_rank: Contributor
timestamp: May 14, 2024, 06:15:07 am
content: up help me please
A multimeter that can do it all - Page 1
Forum section: electronics / beginners

author: edavi
author_rank: Contributor
timestamp: February 15, 2021, 03:42:01 pm
content: Shot in the dark question. I'm somewhat new to electronics. I've been dabbling in graphics card diagnosis and repair, and my cheapo multimeter has done me very well for older architectures. The newer graphics cards have some resistances so low it looks like a short on my current meter. My quest is searching for a meter that can measure at least down in the milliOhm range (microOhm would be nice to have but not necessary), and measure capacitance/impedance is an added bonus. I know of the DE 5000's existence, but I'm looking for something that has all the functions in one. I've found it to be very difficult to search for multimeters that can at least go down to this range! I'm curious to see what options there are on the cheapest side and the nicer side.Thanks

author: wizard69
author_rank: Super Contributor
timestamp: February 15, 2021, 04:47:48 pm
content: If there was meter that could "do it all" we wouldn't have the variety of instruments we have now. You will likely either need a specialized meter or a bench top DMM with a good four wire OHMs capability.At least on the handheld meters I've used, I pretty much ignore OHM readings below about 2 OHMs as there are too many variables to trust the readings. You can null out the lead resistance and so forth if you really need to take the time.

author: RoGeorge
author_rank: Super Contributor
timestamp: February 15, 2021, 05:04:33 pm
content: Quote from: edavi on February 15, 2021, 03:42:01 pmPut a picture with such a resistor. Most probably those are zero ohms resistors, like jumpers, so there is no need to measure them more precise.

author: Simon
author_rank: Unknown
timestamp: February 15, 2021, 05:55:55 pm
content: Please do not create identical topics, it really annoys other users when they find out:https://www.eevblog.com/forum/testgear/a-multimeter-with-low-ohm-resolution/msg3466144/#msg3466144
A n00b's question - Page 1
Forum section: electronics / beginners

author: KernelPanic
author_rank: Newbie
timestamp: January 09, 2012, 11:51:39 am
content: Hello peeps,I have been slowly acquiring a myriad of experience tearing anything remotely electronic to find out how it worked since the tender age of 5.I am currently a compSCI student and have a working knowledge of electronics , soldering , etc..My current dilemma is that i am hoping to setup my home lab to dabble with various electronics projects , and i cannot seem to find any stores in Australia that cater for beginners such as myself.After a LONG time googleing various establishments i came across adafruit industries in America.https://www.adafruit.com/products/136They have a toolkit which seems to be sufficient for someone who is just getting started , trouble is , the shipping cost is almost as much as the kit.Does anyone know where i can get myself a half decent toolkit locally that won't cost me a king's ransom ?Thanks in advance

author: mobbarley
author_rank: Regular Contributor
timestamp: January 09, 2012, 11:58:29 am
content: Go shop at Jaycar - you can handle the stuff and see what you really need. They have cheap stuff and some more reasonable tools too.For the tools you won't use so often go to dealextreme and order away - cheap chinese tools with free postage - but the shipping can take 3-5 weeks.

author: ipman
author_rank: Regular Contributor
timestamp: January 09, 2012, 12:09:47 pm
content: Where are you located? I cannot figure out.And be aware that the prices sometimes reflect qulity, tough not allways.

author: mobbarley
author_rank: Regular Contributor
timestamp: January 09, 2012, 12:31:06 pm
content: And of course:http://www.eevblog.com/2011/04/30/eevblog-168-how-to-set-up-an-electronics-lab/

author: metalphreak
author_rank: Frequent Contributor
timestamp: January 09, 2012, 02:49:08 pm
content: www.jaycar.com.auwww.altronics.com.auhttp://littlebirdelectronics.com/<--- Sparkfun reseller in AUhttp://au.element14.com/<--- free shipping on any online orders over $10. Don't have to be a business, as they gladly set people up on "hobbyist" accounts.The Duratool and Multicomp brands at Element-14 are you best bet for low cost stuff from there.Where abouts in Australia are you?

author: KernelPanic
author_rank: Newbie
timestamp: January 10, 2012, 10:37:28 am
content: Thanks for the replies guys , at least i know where to look now .I'm in Sydney BTW.