Data Sheet

UCTRONICS Ultimate Starter Leaning Kit for Raspberry Pi #K0064
31 www.uctronics.com
3.21.2 Red, Green, Yellow, Blue LEDs
Light Emitting Diode (LED) LEDs are solid state devices that emit light when electricity passes
through them. They are directional and need to go in the circuit the right way around.
Once a certain “on” threshold voltage is reached (about 2V for a red LED) the current
through an LED rises very quickly with the voltage. In most applications, a resistor is needed
to protect the LED from being overloaded due to this effect.