How a Photocell Works - Ben's Question

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In summary, a photocell works by converting light into electricity through a chain reaction caused by photons knocking electrons out of orbit. The current increases rapidly at the start as voltages slightly increase, then levels off before rising again once the voltage reaches a sufficiently high level. This can be attributed to the increase in temperature and subsequent change in resistance, resulting in a curved graph instead of a linear one.
  • #1
bjohnson
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I was wondering if anyone is able to tell me how a photocell works and why results for voltage versus current change the way they do. In particular i am looking for why the current increases rapidly at the start as voltages slightly increase, and then a flattening out occurs, i.e. the current doesn't rise much, and finally why the current starts rising again once the voltage gets sufficiently high enough

Thanks in advance :smile:

Ben
 
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Hi, Ben;
All that I can address is the first part. Photovoltaic cells work because if a proper material is exposed to light, the photons knock electrons out of orbit and a chain reaction of sorts takes place to set up an electron 'flow'. I've never heard of those other stages that you mentioned. Sorry for the limited response, but that's the best that I can do right now.
 
  • #3
Hello! I have no idea here, I've just finished A-Levels, so I don't know a great deal about Physics at the mo, but I think I did some work experience on photocells...

Just quoting Danger, but when the photons knock electrons out of orbit and they make a current, isn't it just a case of, when you have more electrons flowing, therefore a larger current you have a higher temperature, so a higher resistance - meaning the resistance isn't constant, so the graph is curved as it isn't an ohmic conductor...? Just thinking out loud really!

Sam
 

What is a photocell?

A photocell is a type of electronic device that converts light into electrical energy. It is also known as a photoresistor or light-dependent resistor (LDR).

How does a photocell work?

A photocell works by using a semiconductor material, such as cadmium sulfide, that changes its resistance when exposed to light. When light hits the photocell, the resistance decreases, allowing more current to flow through the circuit.

What are the applications of photocells?

Photocells have a wide range of applications, including in light-sensitive switches, automatic lighting systems, burglar alarms, and solar panels. They are also used in cameras, street lights, and traffic lights.

What is the difference between a photocell and a photodiode?

Both photocells and photodiodes are semiconductor devices that convert light into electrical energy. The main difference is that photocells have a variable resistance, while photodiodes have a fixed resistance. Photodiodes are also more sensitive to light and have a faster response time.

What are the advantages of using photocells?

One of the main advantages of using photocells is their low cost and simplicity. They also have a long lifespan and are not affected by vibrations or shock. Additionally, they do not require a power source to operate, making them energy-efficient.

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