P2 - OCR Gateway

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  • Created by: Shruthi22
  • Created on: 06-04-17 22:49

P2 - Collecting energy from the Sun

Advantages of photocells: 

  • robust and are low maintenence 
  • no fuel needed nor long power cables
  • cause no pollution and do not contribute to global warming
  • use a renewable energy source

Only disadvantage is that they do not produce electricity when cloudy or dark. 

How do they work? 

- Contains two pieces of silicon joined together to make a p-n junction. 

One has an impurity to create an excess of free electron (n type silicion). The other has a different impurity to produce an absence of free elections (p type silicon). 

Photons are packets of the sun's energy - they cause free electrons to move producing an electric current. 

The output depends on :-

  • The intensity of light

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