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D.C. Theory © copyright M.J.Morris 2004 |
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D.C. Theory © copyright M.J.Morris 2004 |
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After completing this section you should be able to:
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Why do the electrons move?
The electrons are repelled by the negative charge at the negative terminal of the battery and attracted by the positive charge at the positive terminal. Therefore the electrons drift away from the negative terminal and towards the positive terminal. When the electrons reach the positive terminal a chemical reaction transfers them across the battery and back to the negative terminal. Compare the electrons moving through the cct. to ball bearings rolling down a ramp and the battery to a lift which raises them back to the top of the ramp each time they reach the bottom. |
Conventional current flow
As stated above the movement of electrons and therefore the direction of current flow is from the negative terminal of the battery to the positive terminal. However before the true nature of electricity was known scientists assumed that current was the result of the movement of positively charged particles and therefore that current flowed from the positive to the negative terminal. This (incorrect) convention is still used today and is called conventional current flow. When discussing the true nature of current we call it electron flow. In general conventional current flow is indicated on circuit diagrams and true electron flow is used when we describe how an individual component works.
