diode

Everyday

1. A diode is a small electronic part that lets electric current flow in only one direction, like a one-way door. tree →
2. A light-emitting diode (LED) is a diode that gives out light when current passes through it. tree →

In the lessons

Used in science and technology lessons about circuits: a diode in the wrong way round stops the circuit working. LEDs are in torches, screens, traffic lights and Christmas lights because they use little energy. Phrases: light-emitting diode (LED), a diode in a circuit, forward and reverse.

Examples

• A diode lets the current go only one way. tree →
• We put the LED in the circuit backwards, so it did not light up. tree →
• Our torch uses tiny diodes instead of an old bulb. tree →
• The circuit diagram shows a diode as a triangle with a line. tree →
• LED stands for light-emitting diode. tree →
• The robot's eyes are two red diodes. tree →
• If the diode is turned round, the buzzer stops. tree →

Note

Countable. Say «DY-ode». LED is said letter by letter (L-E-D) or sometimes «led». A diode is not a battery: it does not make electricity, it only controls which way it flows. Its long leg is usually the positive one.