| Intermediate Technology Education | Energy and Power Technology | Pre-Design | Topic 3 | Optional Activity 3 |

Electrical Generation—AC

The purpose of this activity is to learn how electricity can be produced using a magnet and copper wire.
  • Learn that producing electricity using a moving magnet and a coil of wire was the second method discovered for generating current electricity
  • Learn how the electricity produced this way is different in some ways than the electricity produced by a battery

Generating Electricity

Figure. Faraday's Generator—Royal Institute

You use a lot of electricity in your homes. Where does it come from? You might have a few devices using cells and batteries but the majority of the electrical energy you use comes into your house through 3 wires usually attached to a utility pole and power line. The power line must eventually lead somewhere. What is at the far end of that power line?

Michael Faraday

In 1831, roughly 30 years after Volta showed that Direct Current electricity could be produced using a wet cell, an English scientist discovered that electricity could be produced if a permanent magnet was moved near a copper wire. Michael Faraday's discovery led to the development of electrical generators and transformers, an essential part of our electrical grid that we usually take for granted until the lights go out during a winter storm!

A simplified explanation of Faraday's discovery would go something like this. Electrical current is the movement, through a conductor, of incredibly tiny, charged particles called electrons. These electrons are not normally moving through the conductor unless forced to by some energy (in the case of a cell, it is chemical energy).

The electrons have electrical charge but they also have another property, they behave as tiny magnets. Anyone who has ever picked up two magnets understands that there is a force between them. Sometimes they attract, sometimes they repel depending on how you hold them.   When Faraday brought his magnet near the copper wire, the tiny electrons were compelled to move through the wire. This is the electron movement or electrical current he detected using a sensitive instrument called a galvanometer.

In the activity that follows, you will attempt to recreate Faraday's discovery using a similar apparatus and a computer to measure and display the electrical voltage. 

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