316 B
316 B
Calculations
LED Formula
LED Spec:
2.8v (forward voltage) 20ma (current)
Vsupply = 5v (Pi Power) Vf = 2.8v (Led Volts) R = resistor value If = desired current
Vr = Vsupply - Vf R = Vr / If
Vr = 5V - 2.8V = 2.2V R = 2.2V / 20mA = 110 ohms
Make sure to add some play room, we use a 120 omhs resistor