Colour code
LED resistor
4 bands
5 bands
Value
–
Tolerance
–
Could measure
–
Or type a value
Show bands
Supply voltage, V
LED forward voltage, V
LED current, mA
Standard series
E12
E24
Typical LEDs:
Red, 2.0 V
Yellow, 2.1 V
White or blue, 3.2 V
Resistor, worked out
–
Next standard up
–
Current with it
–
Power in the resistor
–
Read its bands