Lesson 3: Light-Emitting Diodes (LEDs)

What is an LED?

LEDs are diodes. A diode is an electronic component that acts like a one-way street for electricity. It only lets electric current flow in one direction and stops it from going the other way. Think of it like a valve or a gate that only opens in one direction. An LED will not illuminate if the anode (longer positive leg) is connected to the ground.

The anode is the positive terminal marked with a (+) connected to the longer leg of the LED (usually indicated by a notch on the LED casing). The cathode is the negative terminal marked with a (-), connected to the shorter leg (usually indicated by a flat edge on the LED casing).