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Diode - GCSE Physics Definition

Reviewed by: Philippa Platt

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A diode is a semiconductor device that allows current to flow in only one direction, serving as a crucial component in electronic circuits. It is composed of a junction between p-type and n-type materials, where the p-type contains an excess of holes and the n-type has an excess of electrons.

When connected in the correct direction, known as forward-biased, the diode permits electrical current to pass through. However, if connected in the reverse direction, known as reverse-biased, it blocks the current, effectively acting as a one-way valve for electricity.

Diodes are commonly used for rectifying alternating current (AC) to direct current (DC) and protecting circuits from potential damage caused by incorrect current flow.

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Philippa Platt

Reviewer: Philippa Platt

Expertise: Chemistry Content Creator

Philippa has worked as a GCSE and A level chemistry teacher and tutor for over thirteen years. She studied chemistry and sport science at Loughborough University graduating in 2007 having also completed her PGCE in science. Throughout her time as a teacher she was incharge of a boarding house for five years and coached many teams in a variety of sports. When not producing resources with the chemistry team, Philippa enjoys being active outside with her young family and is a very keen gardener

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