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?

Topic by Michael2000   |  last reply

Circuits and Circuitboards

I would like to make circuits using paper and a conductive ink pen, but there's not way to "attach" the components to the paper. I'm looking for a conductive glue, like epoxy or super-glue, I can apply directly to the point of contact between the paper and the component. Can anyone suggest a product, or how to make such an item? Thanks, Kevin

Topic by kevin.t.stein.3 

Circuit not working? Answered

Hey Guys, a few weeks back I posted a question about a clap switch with an IC 4017 not working (relay not turning on). Well I tried to make the project again. The problem is now the relay wont turn off (-_-). ( video of the project by another guy ( He doesn't use relay, instead he uses an LED. The problem with mine is that when I give it power the CIRCUIT OFF LED is off and the relay is on, indication that the circuit is in on position, so far so good. But when i clap the CIRCUIT OFF LED turns on indicating that the circuit is off but the relay stays on. The first time I tried, i didnt put the diode near the relay, same result. THen I put a diode (the wrong way), nearly burnt my hand. This time i put the diode in the same way that im supposed to but the circuit still has the same result. I have uploaded the schematics, Hope someone can help me. UPDATE: I was using MJE13003B instead of BC547. When I was using the mje13003b it was very easy to turn the circuit on and it used to come on at first try. When i inserted the BC547 the circuit was in off position I clapped and it worked like a charm the indicator led turned off and the relay turned on. But when I tried to turn it back off, everytime i clapped the status led blinked and thats it, It just blinked, the circuit would be still in on position. I wonder whats the prob since turning it on is easy and turning it off is impossible. NOTE: Now its the same with the on position. Whether its in on or off position same thing happens. In one of the million clap it turns on. Thanks in advance. -Prickly Potato

Question by SA-DIY   |  last reply

Charger circuit

Hey there, I'm planning to build a portable stereo speaker box thingy (you know what I mean). In order to power the 2x10W amplifier I want to use a 7.2V 1400mAh battery pack from an old RC car. As the housing of the box will be sealed I want to implement a mechanism to charge the pack. For this I wanted to achieve 3 things: -If the Power-Switch is turned on, the amp should be powered from the power line -If the Charge-Switch is turned on, the battery pack should be charged -If both of the switches are turned on, the amp should receive power from the power line while the battery pack is being charged. I have thought of the following cabling (see attached picture for a schematic) The blue box is the amplifier, the green box the battery pack and the orange connectors are tamiya connectors (the ones for RC cars) The first switch (marked in green) is a normal DPST switch which establishes the connection with the power line as well as the connection with the battery The second switch is a SPDT switch and activates either the connection between the battery and the amp or the connection between the power line and the battery. Will this work the way I think it will or does this configuration any faults? If the latter, what can I do I have to change? I'm actually really new to electronics, this if my first project so forgive me, if this setup is actually BS Cheers and sorry for the long post ^^'

Topic by Felixkeeg   |  last reply

Switching Circuit

Hi, I want to build a Auto-Switching circuit. I would appreciate if you could help me on circuit. Sorry for my ignorance in circuit design. There are two power sources A and B. The A is 12v and B is 3v.I would be utilizing the power from A only when B is turned On. So an auto switching circuit is required in this scenario. The circuit should sense if B is On, if so it should let A On.

Topic by arunsun   |  last reply

Pulse circuit?

I need to make the circuit that every time it charges the capacitor to a certain voltage (e.g. 5v or 12v) it discharges it

Question by Dantex   |  last reply

Circuit boards

Does anyone know where I can find replacement circuit boards for my Gateway model number vg70 laptop

Question by CarletonG   |  last reply

Circuit tracer???

Can anyone tell me how to make a device that can scan and trace an entire electronic pcb and give a schematic result ???

Question by 10sicnarf   |  last reply

Circuit Timer

I would like to be able to set a time, small like .5 seconds, and be able to power a 12v circuit for that amount of time, any ideas? 

Topic by ReconIII   |  last reply

Circuit design

Hi, I’m hoping someone could help me. I’m looking to design a circuit for a college project that controls a 240v light. The circuit and light will be controlled by a switch however when the switch is first turned on the light needs to remain off (no power supplied) regardless of the amount of time the switch is on. If however the switch was turned on off and on again then the light needs to come on. Any ideas of a circuit and components required to produce something like this? Your help is greatly appreciated.

Topic by Worby10   |  last reply

Charging Circuit

I was wondering if anyone had any ideas on how to make a circuit so that I could charge a battery, but that I can also power an amplifier when the battery is not charging. Currently I have a switch that switches between a charging circuit and powering the amplifier, but I was looking for a way to do this without having a switch that I have to control

Topic by Fozzibehr   |  last reply

Circuit not working?

Hey Guys, This is like the 5th question regarding the same circuit. Maybe its because the circuit is a bit hard to make or .. idk. Anyway I tried it on breadboard and in the 5th attempt it worked but now that i soldered it on the normal perfboard its not working. It doesn't detect the clap at all.(the microphone is properly connected).I dont know what I did wrong. I bought a multimetre recently so if you could tell where im supposed to see what voltage that should make it easier to troubleshoot the circuit. BTW Pin 12 and 13 are not connected because i remember when they were connected on beadboard it wasnt working.

Question by SA-DIY   |  last reply

Circuit not working? Answered

Hey Guys I just made this circuit (schematics provided) and it doesn't work. The problem is that the  at the output of the 2N3906 transistor the voltage is only 0.5-0.7. So that isn't powering anything. I was wondering if anyone could tell me what the problem is. (the first pic is the original and the second one is the modified one with i built). Thanks in advance. -Prickly Potato

Question by SA-DIY   |  last reply

Will this circuit work? Answered

It works, but are there any problems with it that might fry the chip or something? Also, I didn't know if audio ground should be connected directly to the amp ground, and I saw one schematic that had a 10K resistor in between so I just did that.

Question by 7654321   |  last reply

Electronic Circuit

I have a spst relay(operating voltage-12v) using for switching the solenoid valve(24VDC and 0.5Amp) which connected through 24 V battery. relay is again connected to the transistor BJT NPN . So please suggest me that which transistor is most suitable.

Topic by jay_3189   |  last reply

circuit board

I need to make a circuit board for a project. It is all 12vdc, I have a 1a fan and a 6a thermoelectric device one setting 1, plus another 6a on setting 2, and a 3rd on setting 3 So 1 is 7a 2 is 13a 3 is 19a How to make the board. Also a second device has the 1a fan plus a 4watt element, plus another 4w on setting 2, plus another 4w on setting 3 So 1 is 1a and I think 0.4a= 1.4a 2 is 1.8a 3 is 2.2a. I think

Topic by Johnieahenderson   |  last reply

Will this circuit work?

Ok, so I'm building a giant led array and I'm running it off of a PWM chip and a few shift registers. Given the number of addresses and variables I need for each one, I'm guessing that the micro running the show won't like that too much and will be a bit slower than I'd like, and i'm not sure if it will be slow enough to cause irritating visual inconsistencies. This got me thinking, how did tube TVs do it? They had phosphors that slowly released their charge and therefor looked alright. Thats how I arrived at this circuit. Will it pretend to be a phosphor well enough or will it need something different?

Question by The Ideanator   |  last reply

LED circuit?

I recently purchased a few LEDs for a project, 2 blues and four reds. I need a way to power them all for months at a time. Would a nice soul be kind enough to draw up a schematic for me, considering I know NOTHING about this stuff? Here are the schematics, taken right off the back of the packets. 4 Red LEDs: Forward Current: 28mA max Forward Voltage 2.6 V max 2 Blue LEDs Forward (supply) Voltage: 3.7 typical, 4.5 Max Forward (supply) current: 20mA typical, 30mA max Any help?

Question by Rotten194   |  last reply

Circuit help

So, my brother tasked me with making him a customizable doorbell for his house for Christmas (of course he didn't tell me till last week, but whatever). looked around at a bunch of stuff online and found a few decent items. some of them use those voice recorder modules from radio shack...which  might work, but I've used them before and they're pretty quiet. also, not the best sound in general from the mic used to record to them. so I found this thing;=1 which is a riff on this thing  which uses an ATTINY85 to play audio via the PWM output from an SD card. I like this guy because it's gives more options for sound and is generally more "gee whiz". however, the guy built it from scrap parts and has some admitted flaws in it, notably the power supply and the audio amplifier. so, I'd like some help figuring out how to build the same thing, but with a more "correct" power supply and amplifier. also, not exactly an electronics wizard so the fact that there are a billion different chips listed as ATTINY85, I wouldn't mind if someone can make a more sensible parts list (there aren't that many parts). I plan to trigger the thing with an off the shelf wireless doorbell type thing.

Topic by crapflinger   |  last reply

Small circuits and Small circuit wire? Answered

Hi,  I am new to the fiddling with wires stuff. Just about to dismantle a bluetooth headset and I notice that the wire inside is tiny!! I intend to lengthen the wire to the microphone and earpiece but my wire is nowhere near as thin. Will it make the circuit run slower if I put thick wire on thin wire?  If I need it, where can I get thin wire from in the UK?  Also, is there a better nomenclature for thin wire or thick wire or have I nailed it? Thanks in advance Phil

Question by comedy_phil   |  last reply

Is my circuit OK?

I'm building a circuit that uses two 5V inputs and one 24V input. I drew a schematic that I think will work but I want to make sure it does before building it. Can somebody tell me if I'll really get 5V and 24V?

Question by yonch   |  last reply

Random Output Circuit

Hi all I need to create a circuit that, when triggered, closes one of two relays. Any ideas? Nigel

Question by bob_boyce   |  last reply

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.  .  

Topic by csiebe   |  last reply

dtmf circuit problem?

This is the circuit for dtmf based robot using cd4514 for 16 outputs it has 2 l293d ic for controlling 4 motors will this work??

Question by agent555   |  last reply

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!

Topic by FrozenStar   |  last reply

What is this circuit symbol? Answered

I'm wondering what Q22 is, I have never seen that before.

Question by T_T_   |  last reply

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

Topic by RionZion   |  last reply

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!

Topic by hazelcharisse   |  last reply

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.

Topic by Antexter   |  last reply

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.

Topic by YoungOne453 

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!

Topic by Jur   |  last reply

Cree Circuit Board Answered

Hi,I just want to know what a Cree Circuit Board is?Can this be used to connect a cree led to mains 220 volt AC? Here's a link-;=2&m;=2&r;=3&k;=1&t;=1&s;=58305&u;=26110

Question by Adarsh_tronix   |  last reply

Electronic timer circuit.

I have a 9vdc supplying 3ma constant current. I wish to switch polarity automatically every 5 minutes with a timer. How can I do that simply?

Question by rhhince 

Printed circuit bards

I was wondering if I can print my circuit design onto acetate and use it to expose my circuit board. Would that work? If not what could I do instead of of ording them for rediculous prices online?

Topic by pattyshaw   |  last reply

LED Circuit Design?

I'm a Mechanical working in the LED field. I'm trying to design a LED circuit with the little knowledge I have. Here is my circuit in a nutshell: 3.2 Vf typ - 3.6 Vf MAX -.150 mA 24 volt CV PS supplying 3.3 A 7 series in parallel with 22 chains I calculated using typical Vf as the following: 24/3.2 = 7.5 devices so I rounded down to 7 devices in a series chain. 7*3.2 = 22.4 volts required 24 supplied - 22.4 volts = 1.6 volts to dissipate. Resistance = 1.6/.150A = 10.67 ohms Wattage across resistor = 1.6*.150 = .24 W So I found a SM resitor 10.7 Ohms at .25 W. I have a concern with Vf variance. Would this circuit not work if I get Vf's higher than 3.2 Vf? So if I change my circuit to 6 devices per series chain I need 19.2 volts and need to dissipate 4.8 volts. This just seems like a waste.I still do not understand Vf variance. If I design for 6 and dissipate 4.8 volts with a resistor - won't the series chain be starved if Vf goes higher? So how do you accommodate this variance? I just have worries about this design - regardless if I design for 6 or 7. I know some about LEDs but I do not know what happens when I get Vf variance. Does the resistor go at the end of the series circuit? If this is the case then I understand how variance in the circuit would be able to use available voltage - and then the resistor is at the end to disipate what is left over. I've heard concerns that I'm not allowing for more head room #i.e. doubling the resistor value and wattage requirements). If I double the voltage dropped don't I take this away from the LED circuit possibly starving it? I have always assumed the resistor goes at the beginning of the circuit - regulating the current/voltage prior to it entering the LED series circuit.?

Question by oharag   |  last reply

Circuit Design Edumacation

Can anyone direct me to free internet resources that will help me with circuit design? I can usually figure out what type of parts are needed for a given circuit, but am often completely stymied by what specific parts to select - what resistor value, which transistor, what voltage and uF cap? What's available? Thanks!

Topic by homba   |  last reply

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!

Topic by karhas   |  last reply

Parallel Circuit question?

When connecting LEDs in a circuit in parallel, why do you need a resistor for each LED or LED series within the parallel. Couldn't you use 1 resistor connected to the power supply before the current even got to any of the LEDs in parallel?

Topic by mrshow555   |  last reply

Blown Circuit Identification

So I am trying to repair an old hair straightener so that I can use it for some project on another. Part of the circuit blew. I think it was a diode but am not 100% percent sure. If someone could let me know what the part is so that I can possibility replace it.

Topic by Trenyx   |  last reply

LED matrix circuit?

So I am trying to make something like this:   to basically make an LED display on a cap. The thing is, I don't want to program anything, just light up a design, wired with a switch to turn on and off. Most instructions are how to program a display using a microcontroller and transisters, etc. My plan is to use 3mm leds and just solder them together and power it with a 9V. Would that be feasible, wiring the LEDs in parallel strands. Also, I know that I might want to use resisters to make sure the current isn't too high and burn out the bulbs but I'm not sure where to put them in the circuit or how to calculate it. (I can't make a circuit from looking at a schematic either)

Question by AeroGophers   |  last reply

A circuit that turns on randomly

Hey, Another quick questions for the more technically minded than me. I need to make a circuit that turns on randomly between 2 set times. i.e. a circuit that will turn on at a different point between 1 and 3 seconds each turn. I'm hooking it up to a keyboard to stimulate it to press a button, but I think I've that bit sorted! It's getting it to turn on and off randomly that's confusing me. So if any of you geniuses can help!? :D Thanks in advance!

Topic by FreshGarbage   |  last reply

Circuit Design Question

Ok, I have a power source that outputs about .5 volts sometimes, but at other times as much as 12 volts. I want the power to illuminate an LED in both cases, without burning it out. I think I need a capacitor for this but I'm not entirely sure? Can anyone tell or lead me to a tutorial or circuit diagram that shows how to do this? Thanks!

Topic by Joe426   |  last reply

Camera Circuit Problem

Most of these have a inverter with 5 pins. Side A: 2 pins. Side b: 3 pins.Well, mine came with 4 pins total. you can see theres 2 transistors.. MY question / idea.. Why cant u just delete the transistors? Like...Left side of inverter Top = Battery + Bottom = Battery -Right side of inverter: Top = Line to capacitor Bottom = Odly Battery +Is there ANY way i can hook this up Easier? I WANTED to cut the circuit to that super small size, with a LED, Transistor, Diode, and inverter. But .. Thats impossible with these.. and i got 8 of the 4-pin ones!! ARG!

Topic by Killa-X   |  last reply

Need a protection circuit?

Hi i am making my own speaker system. i am using this amp the issue im facing is that a few days ago i power this amp with a smps 12v 1amp supply and it was working fine till something went wrong with the psu and there was a spark in the psu, the major problem which occurred  was that this caused a surge which travelled through the amp to my audio source which in this case was my computer. i ended up frying my sound card . can anyone help me make some kind of protection circuit which allows audio signals to pass through but does not let current from the psu pass through.

Question by cfrek   |  last reply

Circuit Boards and LEDs

Ok I need to know, does radioshack sell circuitboards? or at least those white ones as seen in If they don't then what store can I get them at? Also does anywhere else other that radioshack and the internet sell LEDs

Topic by lighteuplife   |  last reply

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.

Topic by Mutad0r   |  last reply

Circuit Design Help

Trying to build a simple circuit to power a small pump while the sun is out. Here are the specifics: Solar Panel (60 cell mono panel) Open circuit voltage 36.4V DC, Short circuit current 7.96A. Pump 12 V DC, 9A max Using E=IR ,  R=E/I, (36.4-12)/7.96 =  3 ohms Power = V(sq)/R = 24.4/3 =198 watts  I purchased a resistor that meets these requirements and hooked everything in series. (Solar panel lead to resistor, resistor to pump, and pump to other solar panel lead. The pump does not turn on when the panel is in the sunlight. I measure the voltage coming out of the panel and it is within specification. I also tested the pump by hooking it up to a car battery and it works fine. Any ideas what I am doing wrong? thanks!

Topic by OMGIMDUMB   |  last reply

Sound Locator Circuit?

Hey all, Here's an idea maybe one of you solder-jockeys can help me out with: Ever have a sound that you'd like to find the source of, but your ears can't tell you where it's coming from?  I'd like to build a circuit to do that. I was thinking of something like three electret microphones with op-amps between them in differential mode.  That would give three signals that would be, presumably, the ratio of sound coming from each mic.  (And, therefore, an indication of direction.) Of course, I'd also like to get an adjustable bandpass filter in there somewhere to isolate just the sound I'm looking for.  That's the part that complicates all designs I've thought of. And then, if I could somehow figure out distance too, that would be the ULTIMATE! Here's one possible use case: A car makes a funny squeal noise a highway speeds. The mechanic takes out this device and magnets it inside the hood.  He runs a control wire back to the cabin. Once the car is in motion and making the desire noise, he adjusts the BP filter using potentiometer(s) and a pair of headphones. The device tells him where (relative to itsself) the sound is coming from. Your bill is less because the problem was diagnosed quickly without a lot of guesswork. Thoughts?

Topic by PS118   |  last reply

Crystal circuit board ?

Can crystals ( quartz, ruby , amethyst, etc.)  be used in technology to amplify power? keep power sustained, renew power or something ? 

Question by AlexxSolace   |  last reply

Electrical Circuit Help

I would like to make the LEDs in the pre-wired controller in the first picture shown blink to music using the formula in the second.  I was thinking that I would need to leave the +/- coming out of the controller on different power than the LED strips this way you have constant power to the controller and therefore the remote to control the colors.  Anyone know how I can incorporate this?

Topic by chunkyblamm   |  last reply