This diagram covers The AC Generator within Electromagnetic Induction for GCSE Physics. Revise Electromagnetic Induction in Magnetism for GCSE Physics with 13 exam-style questions and 12 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 4 of 14 in this topic. Focus on the labels, the relationships between parts, and the explanation that turns the diagram into an exam-ready answer.
Topic position
Section 4 of 14
Practice
13 questions
Recall
12 flashcards
🔌 The AC Generator
Figure 2: In a generator, a rotating coil cuts through magnetic field lines, inducing an alternating EMF
An AC generator (alternating current generator) works as follows:
- A rectangular coil of wire is placed between the poles of a magnet
- The coil is rotated mechanically (by steam turbine, wind, water, etc.)
- As the coil rotates, different parts cut through the magnetic field lines
- This changing flux induces an EMF in the coil
- Slip rings and brushes allow the rotating coil to connect to the external circuit without wires tangling
- The output is alternating current (AC) — the direction reverses twice per rotation
The EMF is maximum when the coil is parallel to the field (coil sides cutting through field lines fastest) and zero when the coil is perpendicular to the field (coil moving parallel to field lines, cutting none).