LED resistor value

[glewis721]

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)

 

[(*steve*)]

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.

 

[glewis721]

thanks!