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which resister?

Posted: Thu Jul 21, 2011 10:49 pm
by stug 85
hi all jus a small question, i have been wiring in the lights on my 1/6 jeep and putting a switch on the dash.
anyhow i have led's in the rear and i want to run a mini maglite bulb up front but the battery pack is 4 aa batterys about 6 volt where as the bulb is 3 volt does anyone know what type of resister to use? :S

Re: which resister?

Posted: Fri Jul 22, 2011 10:06 am
by Tankbear
Hi Stug 85,

I had simular issue when finding a resistor for the LED tail light. I found on a Honda car forum the below fomular.

Source voltage-LED voltage=result voltage

result voltage/current.

current = power (lamp wattage)/voltage (lamp volage)

So I think following that you'll have

6v (batteries) - 3v (lamp) = 3v

3v/current

But need lamp wattage to work out current.

Hope that helps.

Re: which resister?

Posted: Fri Jul 22, 2011 11:18 am
by stug 85
hi thanks for the reply i think a trip to maplin is on the cards thanks again :thumbup:
mark.