Laser beam security

Hi all, I'm new to this forum and here is my question: How do I find the schematic for the laser beam home security system? Using the step by step explanation the schematic is not displayed. Regards HtG

Posted by HermantheGerman 10 years ago

Relay Schematic

I have a 1 volt signal that I need to latch open a 12 volt circuit for about a minute. Does anyone have a schematic?  

Posted by Divet 6 years ago

Equalizer Schematic

Is there a schematic or a compact way (some compact sound system without all of the cd players and radio and all of that other fancy stuff, my input is just a 3.5mm jack) of creating an equalizer like below? I just thought up a cool project, but no schematics on the internet...

Posted by guyfrom7up 9 years ago

Can someone help me with schematics please?

Can someone please tell me about the capacitors i should be using in this schematic?  Like i know i need a 0.01uf but what type of capacitor? and (V)? also what is a 6pF?   Last question is about the #16 wire.. Im guessing this is just a inductor i can make by wrapping it around a pen 6 times? but do i use magnet wire or any old regular copper wire? thankyou.

Posted by andrewlapham2010 5 years ago

Printed Circuit Board Help...

P { margin-bottom: 0.08in; } Okay I found this circuit that about Attack and Decay but I have no idea what it is...after research, I think its a effects pedal...(leave a comment if I'm wrong.)  So, it is complex so I want to make this into a circuit board but am not too good so some help would be appreciated.   Can anybody help??? Thanks in advance. Make sure you read my image notes. They are very critical to the design...I think.    

Posted by blinkyblinky 6 years ago

Tube amplifier schematic

Does anyone have a schematic for a stereo tube amplifier, I just acquired a large quantity of tubes, a tube tester and some other assorted electronics from my grandfather. Ive always wanted to make a nice tube amp, now all i need is direction. It will be another 2 weeks or so before I can actually pick them up and start testing them so I was just trying to find some schematics to get me in the right direction. I figure this may even make a nice first instructable as long as im not completely lost in the schematic. Thanks smoke

Posted by smoke 10 years ago

Philips schematics

Philips boombox schematic Inappropriate Incomplete Spam I am attempting to add an external jack to a Philips AZ 1564 boombox and need to know where on the amp c/b to tap into. This jack will be for my MP3 player, searching the internet has been fruitless. Does anyone know where I may be able to find this info?   Preferably for Thanks in Advance !

Posted by kalanikaau 7 years ago

Help! Need a tech to build a board. Schematic included

Hey all Sorry for being new to this. I was wondering if I can pay someone to make me this device Please let me know. Thanks in advance

Posted by Nuke209 3 years ago

schematic for emergency lamp

Hi I have T4 Fluorescent Lights (8W 24v '1Feet length') and 6v 4Ah battery. I Would like to make an emergency lamp with these. Can anyone send me a curcuit diagram/schmatic.. Just manual switching on and off will also do. Thank  you  

Posted by nominds 8 years ago

can someone explain this for me?

In the picture of the schematic there is + symbols and i dont know where to connect them, specifically the 10M ohm one, can you lend a hand?

Posted by Yerboogieman 10 years ago

Philips boombox schematic

I am attempting to add an external jack to a Philips AZ 1564 boombox and need to know where on the amp c/b to tap into. This jack will be for my MP3 player, searching the internet has been fruitless. Does anyone know where I may be able to find this info?   Preferably for Thanks in Advance !

Posted by kalanikaau 7 years ago


I noticed that there was a software that was called Eagle PCB design software but it costs money while there is a version that is free. It appears to me they can do the same thing so, why is the PCB design software $49 but the regular software free?

Posted by blinkyblinky 6 years ago

I will paypal someone $10.00 dollars to draw this in breadboard fashion for me!

Hi, I really need help. I've been working on this dern motion detection alarm and am having problems with the delay circuit. I think I have assembled it right and it never works. I have completely re-done it twice! What it is supposed to do is once power from the relay is sent to the 555 timer it will impose a 1 minute delay before sending the power to the alarm/horn. This gives owner adequate time to enter code to disarm. The relay part of the circuit works fine and sends power to the 555 timer and latches as it should. However, the 555 timer never sends power out of pin 3. Could someone please, please, please draw the attached schematic in breadboard fashion so I can double check everything is assembled properly? I would really appreciate it!!! Anyways I will paypal someone $10.00 dollars to draw this in a breadboard layout for me!

Posted by swilus 6 years ago

Schematic Symbol

In this schematic, At the top middle there is a symbol "ODD" that is enclosed in a circle. Can anyone tell me what that is? Im assuming it is the audio jack, but i may be wrong, Thanks

Posted by Grizzly_Bear 5 years ago

Schematic Building Aplication For My Computer

Okay so making schematics is a pain so I was wondering if there are any applications that you can make a schematic with? For instance I could put in a resistor symbol, capacitor symbol, transformer symbol or a speaker symbol ETC ETC and then put in wire and add numbers to identify components and then print it? Are there any applications like that?

Posted by jackillac92 9 years ago

Schematic capture / artworking software.

There are a dozen or so free electronic schematic capture and layout packages around (as node-limited versions of commercial packages). I've briefly tried a few (PCB Elegance, 123 and a couple more) but is there one which is head and shoulders above the rest? I'm looking for good library search and easy component placement and routing. Standard generic symbols as well as specifics, and autorouting and placement. Also ability to save as GIF or JPG. What would other users recommend? Incredible - When I was in electronic design for a living (a fair few years ago) my company spent hundreds of thousands of Pounds on a schematic capture and routing package and the SparcStations to run it on.

Posted by AndyGadget 10 years ago

FREE Schematic publisher(also includeds breadboard and PCB view)IN ALPHA

I did a search and didn't see it on this site anywhere, but I see a huge need for a number of the members here to be able to draw schematics and even simulate a breadboard or PCB. This software is free(but it is still in ALPHA testing). I have no affiliation with this site so I can only answer questions about usability from my opinion. For what a lot of people need on this site to help make "instructables"  that have electronic curcuits in them I think this is perfect. Especially if you can't afford high dollar software, plus if you're not an electronic engineer this software will teach you proper terminalogy and proper drawing designations as well. From what I know, all parts on the program are editable. So if you need a green 3.6v LED you can edit the one that comes default on the program and save it in your tool kit and use it for another project later. Hopefully everybody sees this. If the Mods know of a place to put this where it may be more accesible and visible to everybody here, please move it. Here's the link to find the software. They have it for Windows, Mac OSX, Linux 64 and 32 bit Enjoy PS, don't forget this software is in Alpha, so contact the devs and tell them if you have problems or you'd like to see changes

Posted by navyredman 8 years ago

What do you think of this circuit?

I made a few changes to a circuit, since it's the first time I do this I'd like to know what you think and if there's anything I should change.

Posted by pquadros 5 years ago

Need schematic: 60-LED analog seconds-only clock

I built a "barn-door" tracker to take photos of planets and stars so that they are tracked (i.e they appear as dots, not trails). See if you want more info about  trackers of this type. My tracker can be seen in the first two photos here: These devices depend upon the user manually turning a knob at exactly one rpm for as many as fifteen minutes. This is (very) tedious, but gets good results. The biggest difficulty is in keeping the proper rate of knob-turning. I use a stopwatch timer and have a pointer on the knob so I can manually match each second as it goes by. This has to be done in the *dark*, though, for obvious reasons! So there's an additional problem of lighting the dial and stopwatch. My idea would be to affix a steady red LED to the end of the knob pointer and to use an analog clock consisting of 60 red LEDs arranged in a circle around the knob. Only one LED would be lit at a time, starting at 12 o'clock position, and advancing one LED at a time, clockwise, and keeping each LED lit for one second. This arrangement would let me simply match the knob's steady LED with the currently-lit one and thus makes manual matching of the "second hand" visually easy. I expect a 555 timer circuit (powered by battery, not A/C, for portability) could handle this task, but I don't know enough about electronics to know for sure. I'd like to keep the cost lower than it would be if an Arduino-based circuit were used. I've also never made a custom printed circuit board, but I'm game to try after building a successful breadboard. I just need a schematic!  Thanks, all.

Posted by tjerome 7 years ago


I need some help translating this diagram to a small printed ciruit board I bought from radioshack. I've never done this before and wish to learn. I decided to build this lie detector for my science class science fair project and have all the necessary equipment, I just dont know like what row to put what and emitters, base, and all that good stuff. Please help. Thank you.

Posted by dwatord26 8 years ago

Does anyone have the schematic for a Guitar Hero controller?

I'm working on a hack for my guitar hero controller. It's the model that comes with World Tour, and it is for wii. Does anyone have a schematic for it? A full one would be ideal, but what I'm really interested in is the strumming circuit. Any schematics would be wonderful.

Posted by 4lifenerdfighter 6 years ago

Possibility of an 80 amp 12 volt power supply?

I'm just wondering about the possibility of me building one of these? I basically want to power a car amp inside a house. If its possible, how much money would I be looking at? How hard would it be to find the parts? And would I be better off paying $500 for a good home receiver, vs $200 for a good car amp plus whatever the cost of the power supply would be?

Posted by cvxdes 10 years ago



Posted by kyo-89 8 years ago

Solar charger schematic using mppt

I am facing problems with my solar charger circuit using mppt. The main problem is the mosfet switching followed by the dc-dc converter. When i connect my circuit to MSP430 to give PWM at gate voltage drops across the solar panels. I am using a pnp and npn combination to drive the NMOS IRF540. Please help me with the schematic ..

Posted by akash1994jain 4 years ago

Can anyone help me find some schematics for 120VAC15VDC + 325VDC Power supplies?

Hey everyone.  I am in the middle of a project for which I need to be able to turn my mains 120VAC in to two separate voltages. I need to step it up to 325VDC as well as down to 15VDC. I have two questions.  One is it better to make it 325VDC first then regulate down to 15V? and two, does anyone have any links to schematics or anything that can help me out?

Posted by TheBestJohn 8 years ago

Amateur Radio (AKA "Ham Radio")

I have scoured the internet in search of directions, how to guides, or schematics for an amateur radio (ham radio). However, I can't find anything of the sort. All I can find is pages of "hams" showing off their equipment or pages linking to the same thing. Does anybody have a good simple schematic for a ham radio receiver or transmitter. If not, does anybody know where I can find one?

Posted by gimmelotsarobots 9 years ago

Low battery indicator

Can someone please provide me with a schematic to turn on an LED when a 9v PP3 gets low (~<20%), no microcontrollers, the simpler the better. I am hoping you can do this with a few diodes, transistors, resistors, and maybe some capacitors, but I can't think how this would work.

Posted by andy70707 7 years ago

Joule Thief w/ 555 timer

Hello, I have a question about using a 555 timer with a joule thief. I'm trying to build a circuit for some solar powered bike lights but I have a couple of questions... 1. Am I correct in assuming that it's a bad idea to try to run a TLC555 timer chip from the output of the joule thief? Without a load, it seemed to be pumping out at almost 80 volts. 2. I tried building the circuit so that the two rechargeable 1.2V batteries would power the 555 directly, and then the output would sink and source two transistors alternately, which in turn would switch the LEDs alternately, using the output from the joule thief, which was also powered directly from the battery. That resulted in no LEDs lit and some very hot transistors... Bad idea. The TLC555 chip is supposed to run on a supply voltage of 2-18V, but when I tested it with the 2.4V coming from the batteries, it would source, but not sink... Is there any way to build this circuit so the 555 could blink 2 LEDs alternately while the LEDs are powered by the joule thief? The only alternative I can see that might work would be to power the joule thief from the output of the 555 and just blink all of the LEDs at the same time from the joule thief's output. Any help would be appreciated!

Posted by amklose 8 years ago

Schematics please.

I wish Instructables would show circuit diagrams (schematics) of their projects electrical circuits. I hate trying to figure it out from the photos. We are big boys and can understand schematics.

Posted by warren631 3 years ago

Copy and paste in EAGLE

When creating a schematic in eagle, in a step by step instructions how do you copy and paste multiple components and nets all at once?

Posted by guyfrom7up 10 years ago

IR Robot Control

The cheapest way of wirelessly controlling a robot is IR, right? I'm in need of help for a schematic for an emitter and a reciever (this will be my first IR project). Please don't tell me to google it because I've been looking around and all I've found were vague schematics. I'd probably want to use a 555 timer for the emitter, but the schematics were vague again. For the reciever would I have to use 4, along with 4 emitters to drive 2 motors independently? As in Motor1 front and back, Motor2 front and back?

Posted by guyfrom7up 10 years ago

Ignition Coil

Yes, I just posted something on a flyback. I was interested in that, until I saw this. It got me interested in ignition coils, so I got one new from the autoparts store for $20 (USD). I looked on the site, for the schematic, and realized that I didn't know what the rectangle was. Is it a resistor? I'm new to electronics, what size resistor do I need (if it even is a resistor)?What about the capacitor? I have a 100uf 200v electrolytic one, will that work?Also, part of the core is not in the coil, it's square shaped, could I rig it to work like this flyback circuit?Or this one? (simple driver circuit)?Sorry about the never ending beginner electronics questions, I just really don't have anyone else to ask.

Posted by John Smith 10 years ago

Make a magnetic field detector ?

I dearly want to make a device to measure electromagnetic fields in the house ,since the presence of such has been more than obvious and at times annoying . My CRT monitors behave strange in my room . The geometry of one bends as i turn the monitor in one direction and at the same direction ,my spare one changes color to blueish like pale . Interestingly, they do it in the same direction no mater where i put them in the room . My turntable's (i am in to Hi-Fi gear ) cartridge reacts when i put it in some places in the room and i hear noise come out of the speakers until i reposition the turntable . Anyone have any ideas how i can locate the source ? Some simple device ,or schematic that will give me the ability to measure ,or at least detect to some degree the fields responsible ? Will be thankful for any answer .

Posted by soundsmyth 6 years ago

Can someone convert this schematic to bradboard???

Hi everybody this is my first post. I am getting into electronics and I am no good at reading schematics. I was wondering if anyone could convert this schematic to an eagle eye breadboard view. Any help would be really appreciated. Thanks :) LINK TO SCHEMATIC:

Posted by graphitepanther 5 years ago

Tiny timer with display

Hi I want to make a timer - a very small one - for using in school, for cookling and so on... It needs to have a display with at least four digits, five buttons(reset, on/off, start/stop, minutes and hours). I'm planning on powering it by a CR2032, or another button-sized battery. Does anyone have schematics or circuits I could have a look at? In advance, thank you:)

Posted by simo9836 7 years ago

Technology of the Tube Screamer

Some time a circuit Screams wrong as this foot switch flipflop I can see the arrangement if the design wanted independent control but that would allow a lack of signal.

Posted by iceng 6 years ago

Electronic schematics?

I need a free electronic shcematics Program that checks my circuits.

Posted by OrIsIt 6 years ago

Translating a Schematic to a Circuit Board

I need help translating this schematic to a circuit board. As in which rows to place what due to emitters and bases. I'm new at this, please help.

Posted by dwatord26 8 years ago

Installing CADSOFT Eagle on a flash drive?

Hey everyone, I want to know how I can install CADSOFT Eagle on a flash drive, because I cannot use it at school, because I have to install it on every machine I use it on, because it puts a file in the registry and will not run without it. Anybody have any ideas on how I can do this without getting it installed on every machine?Thanks!

Posted by thermoelectric 8 years ago


I just designed (if it works out) a super efficeint Beam Solar engine that works at low voltages. Before I post it I want to ask a few questions to see if I need to revise my design. 1) MOSFETs work on voltage, no current, right? 2) Do MOSFETs have a voltage drop, like biploar transistors have a voltage drop of about 0.6 volts? EDIT: I got a new design that I want you guys to evaluate that doesn't use mosfets. It's incredibly simple and I want to know what you guys think. How it Works: The solar cell energizes the transformer coil while turning on the transistor. The transistor shorts the circuit and then the transistor turns off, then it repeats creating pulsed dc that drives the stepup transformer. I chose this design because there's very little components and there's no voltage drop across the transistor to the transformer. Theoretically this could run on as low as 0.7 volts, which is good for BEAM robots.

Posted by guyfrom7up 10 years ago

Can Anyone Convert This Image to Eagle Schematic And Board?

Can Anyone Make Me A Eagle Schematic And Board? Please Try To Create.......(I'm new to Eagle) Thanks A lot............

Posted by ElectroPro9460 5 years ago

LED based VU meter schematic.

I've recently bought a new pair of headphones, and would like to add a semicircle of LEDs (Green->Yellow->Red) to each can, LEDs that would light to the music playing through headphones. As a result, I've been looking for a VU meter schematic that incorporates LEDs and a 1/8" jack. Any link to such a schematic or ideas for my potential project would be greatly appreciated!

Posted by dmfunk 11 years ago


Hey, I really need a circuit schematic for a simple low power (under 3.5V) FM radio using the TA2003P IC.

Posted by Unknown... 8 years ago

Need advice to find 12V dc/ac schematics

Hi, Im looking for schematics for a Chicago electric - 2000 Watt / 4000 Watt Peak Power inverter part number 95596 from harbor frieght. i did search there site with no luck, and i could use it asap. Or if you some advice about how I should go about repairing it, that would be great. It simply will not power on. TY in advance for your help :)

Posted by intheshed123 7 years ago

Doubt about suppy to circuit

+5V suppy connector was not  mentioned in schematic  So I added that  Please tell me whether it is right or wrong  schematic and layout is attached below

Posted by ashirwad 6 years ago

555 TImer/Chip Help

I need your help people of Insturctables. I am working on an project, and I need to make a circuit whit a 555 timer/chip so that it makes,for example, an LED light up in every 2 second. I mean when it turns on, it needs to be on for 2seconds than off for 2 second...loop. ON(2 seconds)___OFF(2 seconds)___ON(2 seconds)___OFF(2 seconds)___LOOP I need the output to be 12V. Actually I need it for a fan to turn on and off(the fan runs on 12 volts) Can you help me make a circuit for this, what value of the resistors and capacitors do I need... It would be grate if some one could make a schematic of the circuit in Eagle, or so... If I make an Instructables about my project I will surely mention who helped me realize my idea! Thank you all! -Stanislav

Posted by comodore 9 years ago

Attiny schematics

Recently I've been wondering if I could actually build a cpu, I knew about the attiny and thought that I might try to build it without any chips. (Ambitious I know) I'm pretty experienced at soldering and coding and have been doing both for 17 years so I reckon I can manage it. Does anyone happen to know the whereabouts of any schematics for the attiny 25/45/85? If you do please tell me, it would be a great help.

Posted by MakerBox 2 years ago

Need HELP with mod !!!

I need help powering a timer I salvaged from a microwave oven. Here's the schematic for the board. It needs a -5v power supply. I have a 9v battery and a 7805 regulator. Can anyone help me figure out how to make this thing work?hi-res schematic

Posted by mrshow555 10 years ago

audio amplifier don't understand wire schematic :/   the one i am having trouble understanding is the 20 gain amplifier

Posted by pattyshaw 6 years ago

S.O.S. LED Flasher Schematic Diagram

'Hello everyone,I looking to find an electronic schematic of a small LED flasher circuit thatflashes an S.O.S. light code. 3 short flashes, 3 long flashes, and 3 short flashes, than a 5 or so second delay, than repeats.Hoping to us a 555 timer IC.This is for a science project for my 14 year old.HELP! Thanks.Anyone?'

Posted by mark liles 10 years ago