How do solar cells and batteries differ from electric generators that use rotating machinery?

Solar cells, batteries, and electric generators differ primarily in their energy conversion processes and mechanical requirements.

Electric Generators

Electric generators are machines that convert mechanical energy into electricity. They rely on rotating machinery, where a prime mover (such as a turbine or engine) turns a shaft. This rotation moves coils through a magnetic field or rotates a magnetic field past stationary coils, inducing voltage according to Faraday’s law of induction.123

Solar Cells

Solar cells are solid-state devices that convert light directly into electricity via the photovoltaic effect. Unlike generators, they have no moving parts. When light strikes the semiconductor absorber layer, it excites electrons, and a built-in electric field directs their flow into an external circuit.4

Batteries

Batteries are sources of electromotive force that convert chemical energy into electrical energy. They function through chemical reactions occurring at separate electrodes, which transport charge to create a potential difference. Unlike generators, they do not require mechanical rotation to produce power.5