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LED resistor value

glewis721

Apr 30, 2013
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Apr 30, 2013
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if i am using 3.3 volts and a 1.5 volt LED, what value resistor should i use? (i don't know how much 1 ohm reduces the voltage):confused::confused::confused:
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
25,510
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Jan 21, 2010
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25,510
The answer is 90 ohms (get a 100 ohm resistor).

This assumes you want 20mA through the diode (which is a typical maximum value) and that the resat of the figures you've given are accurate.

Click on the "tutorials" link above and look for the one on LEDs. There's lots of background material and also links to calculators that will assist you in doing the calculations yourself.
 

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