Circuits Answered

Can some one give me a clear definition of a transistor.

Asked by Dr. Kreap 6 years ago  |  last reply 6 years ago


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  |  last reply 3 years ago


Circuit Problem? Answered

Hey guys i just made this circuit ( pic provided ), The problem is when i  clap the led that indicates the circuit is off turns off (power goes to the relay coil) but  the circuit off indicator led turns back on after a few sec and the relay does turn on at all. (Yes the relay works) And another thing I observed is that when i take the coil wires off and attach them to an led instead of relay it works correctly and the led stays on till i clap again to turn the circuit off.

Asked by SA-DIY 3 years ago  |  last reply 3 years ago


Circuit not working...

So I made this circuit (http://niotronic.blogspot.mx/2013/07/clap-switch-with-ic741-and-cd4017.html) but it doesn't seem to be working. When I connect it to power the relay is in on position and the led is off. No matter how many times i clap it doesn't seem to change state. Can anyone please tell me what i could've done wrong? Note: when i touch the bottom of the circuit ( on some pins between 1 and 4 of ic 741) it seems to change state. Help would be greatly appreciated thanks. (This video: https://www.youtube.com/watch?v=zFu0pBvpmIk shows this circuit in action. It seems that he used an LED instead of a relay. I also found similar circuits here: http://www.electroschematics.com/5643/sensitive-clap-switch/    http://www.homemade-circuits.com/2011/12/make-simple-electronic-clap-switch.html     http://circuitdiagramcentre.blogspot.com/2011/12/make-simple-electronic-clap-switch.html)

Asked by SA-DIY 2 years ago  |  last reply 2 years ago


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 (-_-). (https://www.youtube.com/watch?v=zFu0pBvpmIk) 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

Asked by SA-DIY 3 years ago  |  last reply 3 years ago


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.

Posted by arunsun 10 years ago  |  last reply 10 years ago


Soundcard Circuit

I've been looking for a soundcard that will work for what I need for a project I'm working on. I need about 6 inputs I prefer to make it myself, just to make it more fun and challenging :) I don't have much experience with this kind of thing so I need some help. I can't seem to find the information I need by myself so here I am asking for assistance. http://www.netams.com/~anton/usb-adc/index.html The texas instrument pcm2900 chip that is used... Do I need 6 of them for 6 inputs? I need them to be completly separate.  He says he is running 2 inputs off of this chip. I guess the 2 inputs share the converter? When I get to programming I need to have 6 separate data streams (one for each input) Thanks in advance for all advice!

Posted by amplifihip 6 years ago


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

Asked by Dantex 8 years ago  |  last reply 8 years ago


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 ???

Asked by 10sicnarf 4 years ago  |  last reply 4 years ago


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? 

Posted by ReconIII 5 years ago  |  last reply 5 years ago


Protector Circuit?

How can I make a circuit that will protect an LED when I plug it into a traditional light bulb plug?  hint- homemade LED light bulbs.  

Posted by Buzzsushi 8 years ago  |  last reply 8 years ago


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.

Posted by Worby10 3 months ago  |  last reply 3 months ago


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

Posted by Fozzibehr 5 years ago  |  last reply 5 years ago


Circuit Help!

Hi, I'm trying to put together a basic circuit for charging a capacitor/s with a built in LED to indicate when it's charged. I've created a draft on Multism but can't seem to get it to work. I'm a complete novice at electronics and have pieced it together from various schematics I've found. Help please! :)

Posted by si_eng 10 years ago  |  last reply 10 years ago


circuit imprime

Bonjour ,j'ai un ecran plat qui marche 5 s et apres plus rien.je l'ai demonte .allimente plus rien ,ni image ni voyant power.

Posted by riadi 7 years ago  |  last reply 7 years ago


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

Asked by SA-DIY 3 years ago  |  last reply 3 years ago


LED CIRCUIT?

Hi would this work if i used 5 12v Leds(parallel) and connected 3 9v pp3 batteries(parallel) for power, also would the LEDS need there own resistors each? look at image for detail

Asked by jbutcher05 10 years ago  |  last reply 8 years ago


Blinker Circuit

Hi i am looking for a good model for a turn signal circuit. i am trying to make turn signals for my mower (not a joke) and i need a list of parts i need to buy, and a image of the circuit i already have the lights and switches. i would like to have it so a switch is for each side, and   i would also like it to be able to do hazard lights, i dont know if i would be able to do that by switching both switches on at the same time?. but what ever you got to help me would be awesome. thank you

Posted by RC Instructables 6 years ago  |  last reply 6 years ago


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.

Asked by 7654321 7 years ago  |  last reply 7 years ago


Circuit Help

Hi, i saw a video by the king of Random     https://www.youtube.com/watch?v=hCxmn1ERbXc He hand cranks up a drill to charge a phone.. but what i wanna do is similar but different, instead of charging a phone i want to charge a battery and what i need to know is, what component do i need to stop the current from the battery to go back into the drill once i stop cranking so it doesn't depletes..  

Posted by Arghus 4 years ago  |  last reply 4 years ago


Sound Circuit

What I want to do is set up a switch so that every time it is toggled, one of two sounds are played on a speaker (which I also don't know how to connect). How would I go about doing this? This is for a homemade Aperture Science Handheld Dual Portal Device.

Posted by elementcollector1 7 years ago


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

Posted by Johnieahenderson 2 years ago  |  last reply 2 years ago


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?

Asked by The Ideanator 6 years ago  |  last reply 6 years ago


Timer Circuit

I found this simple circiut on jamesyawn.com, and was wondering if and how to change it so that it could time in the minutes, longer than it does already. I don't know anything about electronics, aside from soldering, and basic connections, so try to give a simple-ish answer. I also wondered about what transistor to use (like a radioshack part number). The circuit I was talking about is under "discrete timers".(update, more questions)What kind of timing (like how many seconds) would I get with this?Using the same stuff shown on the schematic?Also, how do I pick a transistor?Are they interchangeable? What specs should I be looking for? If this seems like too much, could someone give me a link to a site that would be willing to help with (very) beginning electronics?AND, how would you recommend making the transfer schematics for home-etched circuit boards? I can't get the component spacing right.

Posted by John Smith 11 years ago  |  last reply 4 years ago


Theremin Circuit?

Does anybody have a theremin circuit that doesn't have coils? I need it to be compact so programming seems ideal. A PIC solution might work...any suggestions? Any other processor is fine also. No, I can't use a light theremin... And no, I can't use Harrison Instruments' because its too big and too many connections. If possible, then this is to be used on fruit flies to see how much activity they do when foreign substances are added. Again, if possible if a PIC solution is used, then can the PIC detect when the flies move because they change an oscillation. Most likely I will wind a coil and place it in the jar and then have it detect. The best way would be to use the PIC to print an output via some sort of display so that the scientific results can be tested.

Asked by blinkyblinky 7 years ago  |  last reply 7 years ago


Of solder and circuits

To dodge an onslaught of summer boredom, I'd like to fart around with small scale electronics projects (LEDs, maybe a circuit board, etc.). I hope that by the time I finish farting around, I would have something nifty to post on this website. Unfortunately, I have little practical knowledge of this stuff (other than what I learned five years ago in high school electronics). I mean, I don't even know how one technically refers to "this stuff." Can anyone recommend some good books or a general method of wetting one's feet before jumping into the pond? Highly technical sources are obviously beyond me at this point, so I'm looking for introductory-level information that can be flexibly applied to whatever bizarre project pops into my mind on Friday afternoon.

Posted by ringtail.jack 11 years ago  |  last reply 11 years ago


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?

Asked by Rotten194 9 years ago  |  last reply 7 years ago


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 http://spritesmods.com/?art=doorbell&page;=1 which is a riff on this thing http://elm-chan.org/works/sd8p/report.html  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.

Posted by crapflinger 3 years ago  |  last reply 3 years ago


Completing a circuit when a circuit is broken

I'm wondering how a circuit is made similar to an alarm. For example, when a point in a circuit is broken, it activates something else (led, etc.$

Posted by cyberguy91 6 years ago  |  last reply 6 years ago


Basic Circuit Question? Answered

I am making a box that when opened will sound an alarm.  When it is closed, the contacts are touching, thus completing the circuit.  When the box is open they are not touching.  How can I make a circuit that will realize when theyre not touching(without using an Arduino or other programmer)???

Asked by crocboy 8 years ago  |  last reply 8 years ago


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?

Asked by yonch 7 years ago  |  last reply 2 years ago


Random Output Circuit

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

Asked by bob_boyce 3 years ago  |  last reply 3 years ago


electronic circuit simulator?

Where can i find a free circuit simulator doesent just show signals but that shows what the things do like leds light and switches switch and stuff

Asked by coleyy 8 years ago  |  last reply 8 years ago


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??

Asked by agent555 4 years ago  |  last reply 4 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 7 years ago  |  last reply 7 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  |  last reply 1 year 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 gates.now 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 11 years ago  |  last reply 10 years ago


EMERGENCY LIGHT circuit

>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 8 years ago  |  last reply 8 years ago


LED Circuit Help

Https://www.instructables.com/id/Romantic-LED-Heart/ 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 5 years ago


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?

Posted by pattyshaw 6 years ago  |  last reply 6 years ago


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?

Asked by rhhince 9 years ago


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-http://dx.com/p/18v-5w-cree-circuit-board-for-flashlights-16-8mm-5-5mm-26110?rt=1&p;=2&m;=2&r;=3&k;=1&t;=1&s;=58305&u;=26110

Asked by Adarsh_tronix 6 years ago  |  last reply 6 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  |  last reply 9 years ago


Diac Triac Circuit?

Hello all respectful members, I hope you are well and busy with learning hobbies. I want to have a Diac Triac circuit that can run on 220 Volts, 10 / 15 Amperes, 50 Hz. main line. This circuit can be connected to AC socket to cut off appliances at line fluctuations, and can be reset by a tiny push button when line voltage become steady. I request to provide me this circuit with components values part # Any one wants to send circuit direct to my email address will also be accepted I hope to get a positive response from participants here. Thanks for consuming your time.

Asked by CREATIVE 10 9 years ago


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.?

Asked by oharag 8 years ago  |  last reply 8 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  |  last reply 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  |  last reply 10 years ago


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!

Posted by homba 11 years ago  |  last reply 11 years ago


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?

Posted by mrshow555 11 years ago  |  last reply 11 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 5 years ago  |  last reply 5 years ago