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gregorygarver.com San Francisco Real Estate Forum
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MRMOM
Joined: 11 Apr 2007 Posts: 4
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Posted: Thu Jul 15, 2004 12:43 am Post subject: LED vdc, mA, and resistor help?!?!?!? |
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| If you have an LED light that operates on 3Vdc at 55 mA, and from your own knowledge you know that it will burn out if you connect it to the 13.8 Vdc electrical system in a car, then what kind of resistor do you need to reduce it without it blowing up (( in Ohms )) |
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Richard_Guttman
Joined: 27 Sep 2005 Posts: 3
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Posted: Wed Aug 18, 2004 4:04 am Post subject: LED vdc, mA, and resistor help?!?!?!? |
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| You need to drop (13.8-3) volts drawing 55 ma,so R=E/I = 10.8/.055 = 196 ohms (200 ohms) |
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