Assessment and Qualifications Alliance (AQA) GCSE Physics Paper 2 Practice Exam

Dynamos produce direct current. This occurs because of the way that dynamos convert mechanical energy into electrical energy. When a conductor, such as a wire loop, rotates within a magnetic field, a voltage is induced according to Faraday's law of electromagnetic induction.

The key characteristic of this setup is that the direction of the induced current remains constant, resulting in a steady flow of electric current in one direction, which is characteristic of direct current. In contrast to alternating current, where the flow of electricity periodically reverses direction, a dynamo's output remains consistently positive or negative, leading to a uniform flow.

Understanding this mechanism clarifies why dynamos are typically used in applications that require a stable voltage output, such as battery charging and in powering devices that operate on direct current.