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Separate Physics · Paper 2 · Foundation + Higher · P7

Electromagnetic devices: relays

Key ideas1 of 3

From a current to a movement

A relay is a switch operated by an electromagnet. When current passes through the control coil, the coil produces a magnetic field and magnetises its soft iron core. The core attracts a nearby iron armature. The armature pivots and moves a contact, completing a separate output circuit. Follow the mechanical movement as well as the electrical connections when interpreting the diagram.

A relay with separate control and lamp circuits, coil, armature, spring and contacts.

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Practice, downloads and sources

Daily 5 · Exam practice · Revision sheet ↓

Foundation + Higher · P7. Use alongside the shared P7 lessons.

AQA GCSE Physics 8463 · 4.7.2.1. Original notes, questions and diagrams. Models are simplified; teaching data are illustrative.