A photoelectric cell, or photovoltaic cell, needs light to produce electricity. Here's how it works:

1. Light strikes the cell: Photons (particles of light) hit the surface of the cell, which is made of a semiconductor material like silicon.

2. Electrons are excited: The energy from the photons knocks electrons loose from their atoms in the semiconductor material.

3. Electron flow creates current: These free electrons move through the material, creating an electrical current.

4. Circuit completes: The current is collected by electrodes on the cell's surface and flows through an external circuit, powering a device.

In summary, light energy is converted into electrical energy through the photoelectric effect. The amount of electricity generated depends on factors like the intensity and wavelength of the light, as well as the material and design of the cell.