brsingr Posted February 5, 2010 Report Share Posted February 5, 2010 questions -what is the equation to find out the resitance in ohms i need for leds. i know it involves the source voltage, the led voltage, and the forward current. also, how do i find the forward current. also, if i wire capacitors in parallel will they all charge enough to cause a jolt upon discharge, or should i go series? i'm worried that the first one will be the only one to charge fully, sort of like the lightbulbs where they gradually get dimmer as you go around the parallel circuit. Link to comment Share on other sites More sharing options...
brsingr Posted February 5, 2010 Author Report Share Posted February 5, 2010 or wait am i getting parallell and series confused? edit:sorry double post edit:yes i am, question still stands though Edit: new question - how to discover voltage requirements of a salvaged LED. just test it with random resistors until it works, maybe? Link to comment Share on other sites More sharing options...
Imoutgoodbye Posted February 5, 2010 Report Share Posted February 5, 2010 Do you own a voltmeter? One o' them nice digital ones? I'll think upon the equation a bit more...my physics are rusty.... Link to comment Share on other sites More sharing options...
Deykari Posted February 5, 2010 Report Share Posted February 5, 2010 Capacitors in parallel will charge and discharge equally. To work out resistance required (remember to connect the resistor in series, even if the LEDs are in parallel) the equation is: R = (Vs - Vl) / I Where... R = Resistance required (per resistor/LED) Vs = Supply voltate (guessing you know this) Vl = LED voltage (voltage required for LED) I = LED current (current required for LED) May be able to supply a little more help with more info, as there are a few rules of thumb you can follow to make things even simpler for working out what you need. As for your recent question, what colour LED is it? Most LEDs have a voltage requirement of 2-4v, red being the lower end of the spectrum. Going by your past exploits, be bloody careful with anything like this, even if you're just toying with batteries. When I first started out with electronics I set fire to my old workplace's workshop from short circuiting across just a battery. Not good. Dey Link to comment Share on other sites More sharing options...
killalou Posted February 6, 2010 Report Share Posted February 6, 2010 What Dey said is 100% correct. Link to comment Share on other sites More sharing options...
Imoutgoodbye Posted February 6, 2010 Report Share Posted February 6, 2010 I get the distinct feeling there's some computer modding involved here....I mean, what else are LED's for? Link to comment Share on other sites More sharing options...
-Totenkopf- Posted February 6, 2010 Report Share Posted February 6, 2010 Wow, wtf? Lights in parallel should all be the same brightness, lights in series will also be the same brightness (provided they are the same globe) just duller. Let me know what you are trying to accomplish and I'll let you know what you need. And what the heck are you doing with the capacitors? They aren't going to do much in a DC circuit but hold charge. The capacitance of capacitors in parallel is additive, whilst in series you calculator the same as resistors in parallel (the more capacitors, the less capacitance). If you can be a little less vague as to what you are trying to accomplish, I may be able to help out. I am an electrician. Link to comment Share on other sites More sharing options...
The-Nameless Posted February 6, 2010 Report Share Posted February 6, 2010 Honestly with what he is asking he is either: a) Modding Xbox/playstation controllers or making a stun gun. Link to comment Share on other sites More sharing options...
brsingr Posted February 6, 2010 Author Report Share Posted February 6, 2010 i've prepped a 360 case for a custom mod. gonna use the green jewel from the original xbox and take the green paint off the back to be left with a clear jewel that says xbox and im gonna put it in the side. and the capacitors i was wondering how they work, a friend was asking me why his tazer glove wasnt working. but im not interested in **** like that any more. im making productive **** Link to comment Share on other sites More sharing options...
Grim_Reefer Posted February 6, 2010 Report Share Posted February 6, 2010 He could be making a sweet oscillator pedal. Link to comment Share on other sites More sharing options...
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