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The diode

Diodes are electronic components which can be used to regulate the potential difference in circuits and to make logic gates.

Circuit symbol for diode


The diode has a very high resistance [resistance: The degree to which a component impedes the passage of current. Shown by the letter R. The unit of resistance is the ohm. ] in one direction. This means that current can only flow in the other direction. This is the graph of current against potential difference for a diode:


Circuit symbol for LED

Light emitting diode (LED)

A light-emitting diode, LED, produces light when a current flows through it in the forward direction. LEDs are often used for indicator lights in electrical equipment such as computers and television sets. As LEDs use a much smaller current than other types of lighting, their use is increasing.

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