P5_projector
Member
Radio Shack in the states sells 3.5v LEDs and you would need a 1/2 watt 5% 220 oHm resistor to power the leds with a 9v battery. Make sure to put the resistor on the positive wire from the LED (the longer wire). oh and here is the formula just incase you dont get the led.
Ohms = ( V.bat - V.led ) / Amp.led.
V.bat = voltage of battery, V.led = voltage of LED, Amp.led = Amp of LED (should be on the back of the package)
Ohms = ( V.bat - V.led ) / Amp.led.
V.bat = voltage of battery, V.led = voltage of LED, Amp.led = Amp of LED (should be on the back of the package)
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