How does photocell work?

Answer 1

Best Answer - Chosen by VotersActually "photocell" can refer to lots of different things and you are talking about two of them! Let's agree that photocell means "thing that is sensitive to light".

1) A light dependent resistor uses a chemical (typically a Cadmium compound like cadmium sulfide) that changes resistance when exposed to light. It doesn't convert light to current. To use one, you have to provide voltage and measure the change in current as the resistance changes (or you could provide a constant current and watch the voltage change; same thing).

2) A silicon photocell (or solar cell) generates electricity from light. Photons (light particles) hit the silicon and cause electrons to flow out of the silicon (a little more complicated, but you asked for simple).

3) A photo transistor uses light to turn on a transistor. Actually all "regular" transistors are light sensitive. A photo transistor is made to be sensitive and has a window in the can to let the light in.

4) A photo diode is sort of like a photo transistor but used a diode.

That's all from memory, but I think that about wraps it up. Some of these things are really the same things packaged up or specialized for a certain task. But a light dependent resistor is not an electric

Answer 2

A photocell is an sensor that is supplied by a power feed and switches a load e.g:500W light when it becomes dark, letting electricity flow from mains side to the load side of the sensors relay therefore activating the light.

A photocell is just that. Photo means light. It can control a door buzzer or light the porch when some one come up to the house. It changes resistance with incident light. A circuit can be built to use that change.