A diode is an electronic component that allows electricity to flow through it in only one direction, like a one-way street for electric current. If you try to send electricity through a diode the wrong way, it blocks the flow almost completely.

Think of a diode like a turnstile at a subway station that only spins one direction. People can walk through going forward, but if someone tries to push it backward, it won't budge. In the same way, a diode lets electric current pass through in one direction but stops it from flowing backward.

Diodes appear in almost every electronic device you use: phones, computers, televisions, and game consoles. One common use is converting the alternating current from wall outlets (which constantly switches direction) into the direct current that electronic devices need (which flows in just one direction). Diodes also protect circuits from damage by blocking electricity that might accidentally flow the wrong way.

Some special diodes called LEDs (light-emitting diodes) produce light when electricity flows through them. The tiny lights in your digital clock, the indicator lights on your computer, and many modern light bulbs are all LEDs.