Monday, November 29, 2010

Electric Current

An electric current is a flow of microscopic particles called ELECTRONS flowing through wires and electronic components.
It can be likened to the flow of water through pipes and radiators etc.
As water is pushed through pipes by a pump, electric current is pushed through wires by a battery.
Hot water does work by heating radiators.
Electric current does work by heating fires, lighting lamps, ringing bells, electroplating etc.

A basic law of the universe is that like charges repel and unlike attract. Two negatives will repel each other. A negative and a positive will attract each other.
An electron has a negative charge.
The negative (-ve) terminal of a battery will push negative electrons along a wire.
The positive (+ve) terminal of a battery will attract negative electrons along a wire.

Electric current will therefore flow from the -ve terminal of a battery, through the lamp, to the positive terminal.

This is called electron current flow.

The current flows round the circuit.

In some books current is said to flow from +ve to -ve. This was guessed at before the electron was discovered. They guessed wrong! This is called conventional current flow.

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