Introduction to photocells

(Part 1)

How Does A Photocell Work?

What is a photocell?

How Does A Photocell Work?

By photocell, we mean a photodiode.

What is a photocell?A photocell is an electronic device that converts light energy into an electric

current.

How does a photocell work?Photocells produce electricity from light by the following process: 1. Energy absorbed by the silicon crystal in a photocell2. Negatively charge electrons are knocked loose from the silicon atoms in the crystal3. Electrons flow freely, creating an electric current.

You should know...

Know that photocells:a) transfer light into electricity,b) produce direct current (DC),c) can operate in remote locations,d) have a power or current that depends on the surface area exposed to sunlight.e) DC electricity is current in the same direction all the time

You should know...

The current and power produced in a photocell depends on:

a) light intensityb) surface area exposedc) distance from the light source.

Photocells

Photocells consist of two types of silicon crystal. When light energy is absorbed by the silicon:i. negatively charged electrons are knocked loose

from the silicon atoms in the crystalii. the electrons flow freely, creating an electric

current.

How does a photocell work?

Photocells produce energy by the photoelectric effect. The photoelectric effect is when particles of light (photons) strike the surface of a metal (photocell) and an electron from the metal is ejected. The energy of the photon is transferred to the kinetic energy of the escaping electron, and some of it goes into removing the electron (this is called the work function of a metal).

The power output of a photocell increases as the exposed surface area increases. It also increases as the light intensity increases.

The Sun provides a stable source of heat and light energy. Photocells transfer light

into electricity, and glass can provide passive heating for buildings.