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Old 07-07-2008, 05:54 PM   #1
ricodued
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Member#: 144998
Join Date: Apr 2007
Chapter/Region: MWSOC
Location: Marquette, MI
Vehicle:
2005 Impreza RS
Silver

Default Having an issue working out my circuit for cupholder LEDs

I've two blue LEDs which I will place into the bottom of my two cupholders (one each). They're 5 volt, 30mA LEDs and I'm having an issue recalling my high school physics.

I've got a circuit diagram with my two LEDs, taking up a sum total of 10v from the 12v tap in the cigarette lighter, so I need a resistor in the circuit that will knock out the remaining 2 volts. However, without the amperage of the cigarette lighter tap, I've no idea how to calculate the ohms with V=IR since I have no I (the amps).

Ideas?
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