circuit board

 Hi guys, I am looking for a high quality circuit board manufacturing  that can deliver high quality  circuit board ASAP and with fairly reasonable cost .  any suggestion?

Posted by Michael2000 3 years ago

time safe circuit

I'd like to make a time locking box that is equivalent in function to this: I was wondering if there's anyone out there that would be willing to draw up a circuit for it as electronics is not something that I know how to do.  I could do it with arduino but I don't really want to tie up the board that way.  I assume it uses solenoids to operate.   I'm also open to any other ideas/advice people have.  .  

Posted by csiebe 3 years ago


Im trying to make a singe row 18 LED circuit, i used 18 random resistors that i salvaged from things (one for every led), i connected that to a 12v battery and only 4 light up, (1 out of the 4 are dim, the other 3 are good) what do i do to make all 18 light up. (the LEDs are blueish)?

Posted by Emomo 2 years ago

Help with a simple circuit

Heloo, I have hassled with this since last year. I have googled over 9000 times, yet I still remain confused, and unable to find a solution myself. I guess it's prime time to seek help from others. What I have: Lazer; 4,5 V, 150 mA 2x motor; 1,5 V, 250-300 mA 1x motor; 1V, 50 mA (vibrator motor from nokia phones, and it might work with less) The idea: I made a.. Thing.. that had 3 small motors ( the phone ones) that had mirrors on them and the lazer pointed at them, which eventually reached the wall and made made pretty stuff on it.. But that was a prototype, held together with tape, and now I have decided to make a better one. The V2 of it is held together with screws, has better mirrors (v1 had small fragments of an old hard drive disc), better motors, and looks nicer. If possible then I would like to be able to control the speed of the 2 bigger motors( to be able to create different images) The problem: EVERYTHING!!! I somehow managed to make the V1 without any resistors without burning anything out, so it only had switches and wires. That doesn't seem to be possible with the V2 that I have planned. I have read almost everything on the internet about it, but I can't make much sense of it, so I figured if someone was to show me how it's supposed be, I would understand a little more. Maybe even finish the project. What I want: HELP. You may try explaining what I need to do, but all the laws are sooo confusing. I will appreciate any and all posts, be they not on flames. But what I guess would help me the most, is if someone managed to show me exactly what components I need, and where to place them.

Posted by Mutad0r 7 years ago

How to make 18650 circuit protection?

Help me to build circuit protection for single cell without IC. I need schematic too. Thank you.

Posted by myhobbies 4 years ago

Came across this circuit on some gallery and got curious. what does this circuit do?

I found this circuit while on some image gallery but I want to know what it does! I did some research and does this circuit have anything to do with truth tables?  So could you please tell me, what the purpose of this circuit? and whether truth tables are involved? Thanks Dan1001

Posted by dan1001 5 years ago

Driver circuit for coil over plug

I want to use a COP ignition coil to create a spark for a single cyl antique engine

Posted by molddave 6 months ago

Looking for pre-printed circuit boards

I've been looking around the web trying to find a place that sells ready made circuit boards, plated and pre-drilled; like what you would find in Radio Shack but with a larger selection. I've looked at Mouser and their selection is rather limited. What I need is a circuit board about 1" square for mounting tactile buttons on it.  Like I said I've been looking all over and all I can find are websites that make custom circuit boards, but nothing already made. So anyone know of a place where I can buy already made circuit boards?

Posted by wickednick 5 years ago

Wanted: Someone to build this LED circuit for me...

Can someone build me this circuit that is featured on YouTube? Please contact me with a price. Thank you very much.Here is the link: email me directly. Thank

Posted by corlando52 9 years ago

Would This Circuit Work?

A while back I designed this circuit, and to my knowledge it should work, but I just want to get a second opinion. It is a game in which there is a circle comprised of 12 LED's and the goal is for the user, to press a button, and stop clock so that the green LED in the circle is lit. There is another switch in the circuit so that the user can reset the game at any time. I'm sorry that the picture is very faded and a bit cluttered. Any help is appreciated, thanks!

Posted by FrozenStar 6 years ago

simple logic circuit

Uuhhh..I'm not really sure about this..i'm an electronics engineering studentand my instructor in Logic Circuit and Switching Theory requires us to make a project which will include logic i searched in the net for some ideas i found two..but i know i shouldn't copy their projects..can anyone help me?link2link1thanks guys!

Posted by hazelcharisse 10 years ago

Help with battery charger circuit

I have a slot machine with a 3.6v rechargable lithium battery on motherboard. The problem is the battery goes dead after about a week and the settings are lost. I want to attach a solar battery charger to it so I do not have to leave it plugged in. Could I run the output of the solar charger through a comparator and then to the battery while it is still in the circuit? The panel puts out around 3v in the room I want to use it. Would this be enough to power an op amp? Then when the battery reaches a certain voltage the comparator changes output and stops charging.  If so, would this work? Any advice on how to build the circuit?

Posted by aballworth 5 years ago

need help led circuit

Hello to all I need help to complete this circuit I want to make a flashing sign for my shop window and have to say that i am new to all of this, but a old dog can still learn, i know a few basics and thats about it. I found a 6v dc circuit on one of the sites that uses a 555 timer and 4017 ic and built a bread board circuit that works but it has one led per output 1) i would like to add +- 20 LEDs to each output (10 strings of +-20 leds). Q) what would i need and how? 2) i want to install a pot to alter the flash rate. Q) what would i need and how? I do have a 12v dc reg supply on hand. Please check the circuit picture and let me know what needs to be done to get it to work It would be much appreciated for any and all help received by all the great minds on this fab site MYKEYB

Posted by mykeyb 9 years ago

Simple PIR circuit, need review

Hi, I'm working on a simple circuit. The idea is to have a portable device that lights up when I stand up at night. I have a PIR sensor that triggers 3 LEDS. I use a LM741 as an OpAmp The leds are type 3528. Though these LEDs are supposed to be powered with 12v, I'll use a 9v battery. My main concern is the battery life, tha'ts why I use 100k resistors in stand-by, to limit the current. R3 is used to fine-tune the threshold on the inverting voltage. PIR outputs:    3.3v when it detects motion,    ?v otherwise (but yet >0) Could anyone give me some tips or advice on how to improve my circuit? Thanks, Antonio

Posted by stills 3 years ago

Need Help Making Circuit

I am working on a small weekend project that involves taking the power from the location on the PCB in a keyboard where the LEDs were and making it act as a switch to a small remote control outlet (Something Like This: )I have tried using an LED glued to a photocell, though I am thinking it is somehow acting as a resistor and limiting the power that can go through. I have some transistors, What kind of a circuit can I rig up with them to make this work?

Posted by DELETED_benjgvps 9 years ago

Solar Circuit Question

Hey everyone, first post here. I am a novice at electronics. I am putting together a solar powered boombox. I have a 30w panel, a 10A charge controller, and a 7Ah SLA battery. I will be using this to run a 12v Lepai amp. Do I need something in my circuit that disconnects the amp when the battery drops below a certain level? I have read the if a SLA battery is completely depleted it will be ruined, is this true? My charge controller only has a spot for solar in and battery out. Should I exchange it for one with a spot to hook the load?

Posted by jmitchell51 4 years ago

constant power with timed output

Hi all,           So ive found a circuit that i wish to use found here:;=usb&ModuleNo;=220003&C;=SO&U;=Strat15 its a temperature activated circuit so when it gets to say 30 degrees celcius it switches the relay and makes the connection what i need it to do is when it reaches the designated temp, give a momentary 12v for 2 seconds then do nothing for 1 minute, if it is still at the designated temp after 1 minute give another 12v for 2 seconds then nothing for 1 minute and so on and so on untill the temp drops below the designated temp and the circuit will no longer be live untill it reaches temp again. is there any easy way to modify this circuit or another way to do this thanks

Posted by newbie308 7 years ago

Can I reprogram this?

This is for a LED USB BULB, can i reprogram it?

Posted by SelinA4 7 months ago

Need Circuit Diagram for 5 Watt 12v LED Connect to 6v 5Ah Battery

Hai Friends, I have 5 pieces 5 watt led's. Led Specifications: Model - 5 watt, Forward voltage (VF) DC 9 - 12v, Forward current  (IF ) - 900MA, Output lumens  - 800 - 900LM, Color temperature -  6000 k, operate voltage - 9v to 12v DC I want to connect these Led to a 6v 5Ah Battery. (Used in emergency lamps.I want to replace the old tube light in the batteries and replace with these led's.) I need the circuit diagram for the project.With Low and high Brightness modes.Please help me. thanks in Advance to those people, who are going to help me completing this project....

Posted by jinto1729 3 years ago

Circuit Help Needed

Hello, i need help with a project for school due in 3 months. And i  need help with a circuit with some odd requests.  A variable resistor will change the voltage from 1-18v.   From voltages 1-10v will heat up a peltier tile  and from voltages 11-18v will change polarity around causing the peltier tile to then cool down but at a faster rate. This all needs to be done without a switch and only with the  variable voltage.  If 1-18v is not possible 1-12v may be even better.    So voltages 1-10v will heat up a peltier tile and from voltages 11-12v will change polarity around causing the peltier tile to then cool down but at a faster rate. And again without a switch and only with the variable voltage.  Thanks! -Jon-

Posted by MRCmegarallycar 4 years ago

E coli incubator

I am building an incubator for ecoli.  Any comments or improvements?

Posted by drystreams 8 months ago

Bypassing a multi function controller

I have just bought a laser nebular disco thingy off ebay (incorporating a red and green laser) - and whilst its works fine, I don't like the fact that it switches between various modes automatically (flashing, steady, red only, green only etc).  I opened it up to get some pictures of the circuit board - and wondered if anyone with knowledge of electronics could point me in the right direction with regards to bypassing the multi function controller on the circuit board.  I just want both lasers to remain on all the time. Thanks

Posted by Bunglinpie 5 years ago

LED circuitry help

Hello, I am wanting to make an LED circuit consisting of 11 blue LED's and a 9v battery. Can someone tell me which LED's to use, which resistor to use, how the LED's should be aligned (series/parallel), etc. for this? I do not know electricity very well at all and would rather not screw this up. Thank you

Posted by jgruber1 5 years ago


I would like to know if someone could draw up a small circuit using  a TIP3055 as a switch for these led lights,Im running these off a small circuit for a pir sensor, that uses a relay, and i want to use a Transistor or a mosfet  because of size. I just cant do the math for the are the spec. for the led lights."Working input voltage :12vdc working power 36W . working current 5 amp I know that you have to feed the Base with a lower voltage, and the emitter goes to ground, and the collector get the 12vdc. tks for the help. I never was good at algebra in school, don't even remember it,  ha ha ha

Posted by conntaxman 5 years ago

Can someone look over this picture on Circuits with LED?

Ok, After countless stupid topics and stupid questions I just made a quick circuit in 5 minutes, to see if whatever I'm thinking in my head is correct. I really do need someone to verify, I plan on doing a bigger project after I understand how resistors work and all that nonsense. According to my calculations, I have 1 LED, Green, which runs 2.1V at 20mA. To power this, I used 2 1.5V AAA batteries. So that means I have 3V powering a 2.1 V LED. I have to drop .9V, so I did .9V/.02mA and got 45ohms. I need 45ohms of resistance to deliver 2.1V of power to the LED. (In the pic I used 3x15ohm resistors, again, I don't know how to wire them either...) Now This is my wiring, I am not sure how you link up resistors, I linked them all to the negative wire which I think was wrong...Someone please verify though.

Posted by Cygnis 10 years ago

Circuit Board Help

I have a Sony hcd-fx10 dvd home theater system, and one day I turned it on and it went into protect mode. I contacted Sony and they said it needs to be serviced. I found a service manual online and took the unit apart. I consider myself handy, so this was not a problem. Upon further investigation and with use of the service manual, i found a brown burn mark on the bottom of the motherboard, which corralates to the protection detection module on the board; which is my prblem. My question is, Can I simply remove this module, or does it need to be replaced with a new one or something similar? I don't know much about circuitboards but have some skill at soldering. Attached are pictures, the best I could get of the small board, showing the actual module on the board and the burn mark on the bottom of the board. Any info would be great. Thanks.

Posted by jmmybear730 9 years ago

DVD player: Burned circuit repair

My old-ish dvd player (with surround amp) suddenly broke as I turned it on. The speakers began to hum, and as I immediately switched it off, a column of smoke actually rose from underneath it's hood, stinking off fried component... I've opened the player/amp, and immediately located 2 user-accessible fuses that are definitely bust. However, something elsewhere must have broken/shorted, thus causing these fuses to blow (obviously). Is it possible to locate the source of the problems, and perhaps replace the components? I was hoping to find some unmistakable signs of fire, or some exploded caps. Some components do seem to be fried, but how can I be sure I've found the damaged ones? Also, from my intermediate engineer's point of view, my diagnosis is that someone has, at some time, spilled something into the player (note the pools of goo highlighted in the photos attached to this post), which may have shorted out some components. If anyone has some tips to help me along, it would be great! Please have a look at the photo :) - JK

Posted by joakimk 10 years ago

proximity chip relay

Not sure if in correct forum but here goes... I'm wondering if someone could design a simple and inexpensive way to use a chip to trip a relay with proximity. An idea I have for vehicle anti theft. possibly to bypass need for ignition barrel etc. but to allow the car not to be started without the presence of a close by chip. any ideas?

Posted by astrosurfer 10 years ago

I need some PCB help

I'm trying to help a friend make a PCB for a project of his, but I've never made one myself. Using westfw's design rules in Eagle Free Edition, the board is riddled with jumpers, but there are only three with the default-width traces. I ask you, O wise Instructables community, what should I do?We were going to use the iron-on laser printer resist method, but that won't work if it is too sloppy to make thin traces. How thin can the traces be made with this method for a beginner? We also are considering using this film, in hopes that it will be a little easier to use...does anyone have experience with it?The other option that comes to mind is transferring everything to ExpressPCB instead of Eagle, in an attempt to make a bigger board that could use bigger traces.

Posted by CameronSS 9 years ago

Johnny Walker Game caller wont work properly

Guys(and gals) i need help once again. While I was looking in my friends garage i saw a Johnny Walker game caller and these things are expensive so i asked him about it and he said it didnt work. So ofcourse i offered to try and fix it, and he said if i can that i can use it anytime. (and if you have a good memory, you will remember the post i made about how to make one of these game callers) Well, its power supply is 12 volts DC, 2 6v batteries ran in a series. and they are rechargeable by the way. when i plug the recharging plug(you dont remove the batteries to recharge, there is a port right under the place for the cassette) and hit the power button the red LED(that signals power) is at full strength for about half a second then fades to a wimpy red color. at the same time the LED is at its full power there is a noise coming over the speaker and the noise dies once the LED dims. Any suggestions?

Posted by ledzep567 10 years ago

LED circuit on flashlights

I have over 2 months trying to understand the circuit that LED flashlights have  that last a lot, yhe Joule Thief is not the circuit, because the flashlight circuit is just a capacitor, a resistor and a transistor.

Posted by GeorgeElectronics 3 years ago

Touch switch circuit not working?

Hey, i'm making a touch switch for a USB powered desk lamp, and the touch switch isn't working. The circuit diagram, layout and pictures are below. I used the circuits from the following two websites to design the circuit: the 4th circuit.     I've joined the output of the touch switch to a transistor that should activate the toggle. But the output of the touch switch appears to be constantly on. Can anyone see a problem with my circuit design or circuit?

Posted by Detective Inspector Me 5 years ago

Soft Circuit Contest - Deadline Approaching!!!

Get your entry for the Soft Circuit Contest in before the deadline: October 11th!!!!!!! Check our soft circuit channel and guide for ideas and inspiration. Prizes include Lilypad Arduinos and others brought to you by Fashioning Technology - a fun blog with excellent soft circuit tutorials and resources.

Posted by Carleyy 7 years ago

Soft Circuit Contest Deadline Extended!

We are extending the deadline for entries for the Soft Circuit Contest until October 11th!!!!!!! Check our soft circuit channel and guide for ideas and inspiration. We have some great prizes brought to you by Fashioning Technology - a fun blog with excellent soft circuit tutorials and resources.

Posted by Carleyy 7 years ago

Soft Circuit Contest - Next Week!

We are launching a Soft Circuit contest starting next week! Instructables has a great soft circuit channel  that will provide you will tons of inspiration.  Check out these other websites for tips, tools and ideas. Fashioning Technology Soft Circuit Saturday I Heart Switch Lilypond

Posted by Carleyy 7 years ago

Soft Circuit Contest Deadline Extended!

We are extending the deadline for entries for the Soft Circuit Contest until October 11th!!!!!!! Check our soft circuit channel and guide for ideas and inspiration. We have some great prizes brought to you by Fashioning Technology - a fun blog with excellent soft circuit tutorials and resources.

Posted by Carleyy 7 years ago

Need to build a circuit board

I need to build a small circuit board, with a timer and a led light, small as a nickel, I will provide more details. any idea?

Posted by danielm 10 years ago

LM35 circuit design

Hi, any advice on putting an LM35 into a circuit to control a small (120w max) DC immersion heater element so that it maintains water temperature around 38C ? Thanks

Posted by RionZion 1 year ago

disposable camera charging circuit

Why doesn't the transistor in the inverter circuit of the disposable camera ever heat up? dont they need heat sinks? can anybody pls show me a schematic of a simple disposable camera charging circuit? pls show the transistor number and type

Posted by buddybro 4 years ago

Basic LED Circuit?

I brought 5 RGB LED's just now on the interweb, but I have no clue about circuits all I know is theirs parallel circuits which I will be using and I have a power source of 2 AA batteries. Sorry for such a newbish question, any links to and learning articles would be greatly appreciated.

Posted by Antexter 10 years ago


>i want a design of an EMERGENCY LIGHT circuit pcb> >i want it to run two 61 cm 20W florescent tube lamps> >the circuit should have a key to turn on or of and a key to operate one or two lamps> >u may use one key as u like , operation time on battery is 3 hours as minimum .> >i may buy the design after testing it .

Posted by spyman114 7 years ago

LED Circuit Help

Https:// I would like some input on making this using a 555 timer and POTs to make an adjustable fade in/fade out circuit while running on a 9v battery and using a pressure switch to turn the LEDs on when the box is opened.

Posted by YoungOne453 4 years ago

Would this work? (simple circuit diagram)

Well, i'm pretty much clueless about electronics, so I was just wondering whether or not this diagram would work, and if not, why? Thanks =]

Posted by Weissensteinburg 10 years ago

What is this? (speaker circuit)

I found a pair of broken speakers in a junkyard a while ago and wanted to take the good-looking connectors. When I removed them from the chassi I saw that there was a circuit board on the other side and now I wonder what it does. At first I thought it was an amplifier, but there is no connection for power or batteries. I made some schematics of the circuit, I hope that will help. Gogo gadget, internet community intelligence!

Posted by Jur 9 years ago

inverter circuit

I have several BD139 transistors, several types of transformers, blocker diodes and 40pf 50v capacitors. can anyone show me a simple schematic to convert low voltage to high voltage?

Posted by buddybro 4 years ago

Circuit for multiple LEDs

Hello to all, I'm attempting to use a new nano-technological material (which is conductive) as both a resistor and as a conductor in an LED circuit (it works well as both). At the moment I have a parallel circuit with a 9v battery source and about 10-15 white LEDs..problem is only the first 3 are lighting up (at least with a decent amount of light). Do I simply need to change the circuit to a series or is there something else I can do to get an even (and bright) distribution of power through about 10-15 LEDs?? I would also rather only use a 9volt battery if I can help it. Thanks for any advice :) ~Kate

Posted by kemi 10 years ago

Parallel circuits question

I am trying to make an LED grow light and I have an electrical question. I want a simple light grid, but I am not sure on the math. I understand how to calculate a the resistor needed for a series circuit with a power source and several LEDs, but I do not grok the math for parallel circuits. Can all of the parallel series equal the total voltage? Do I just add the amps from all of the LEDs to figure how many series I can run parallel? Or am I completely off track? Thanks for the help!

Posted by karhas 6 years ago

Best DC Motor Starter Circuit I ever Saw

I wish I had drawn this very good DC Motor Starter control. There are enough questions about a starter box, this is one. It has everything you need to wind up a big machine. A

Posted by iceng 6 years ago

Help with DC motor control circuit

I am looking for some advice in regards to a DC motor control circuit i am trying to build out of some electronic parts I have lying around. See attached control circuit diagram.  The idea is that a timer will trigger the relay to either run the motor in reverse at full voltage or it will run forward stopping and starting as per the wave form from the 555 timer. So on for about 2 seconds and off for about 2 seconds. This waveform can be changed using R1 and R2 which are trim pots.  The circuit works as expected until I hook the motor up. When the motor is meant to be following the waveform from the 555 it will actually stop and start very erratically. Any help on the reason for this would be great.  Also this is one of my first electronics projects and any feedback on my design would be appreciated. 

Posted by jmullo 2 years ago

Wireless, Wireless, WIRELESS! Help with circuits

Heyall, I just have a seemingly easy problem, but apparently it's not. Everything out there is wireless, doorbells, your electric car key, the fan control, garages, my bike speedometer. With so many wireless circuits, why is it so difficult to find a cheap, inexpensive circuit that a hobbyist can make? No, I didn't mean buy a circuit then mod it. I've searched all over and it's so hard to find a simple wireless solution that includes both a RX and a TX. I've seen Xbee but that's something I would have to use with my Arduino. It's also not exactly 'cheap'. So that get's crossed off the list. Are there any schematics for simple wireless RX/TX button or two that works up to 50 feet? What about schematics for a wireless circuit that works up to 100 feet? For my RC plane I have this TINY receiver that has six channels. The transmitter isn't that big either and it works up to 1 mile! But instead of paying 25 bucks for 1 mile and 6 channels, what about 1 or 2 channels for a 10 dollar circuit? See what I'm jabbing at? I don't want to by a doorbell then start unsoldering stuff from board to mod it! With so many wireless applications out there this should be a walk in the park! If you can give help me I would GREATLY appreciate that! Thanks!

Posted by HavocRC 4 years ago