# source of potential difference

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#1
I understand that potential difference is the difference in energy across a component but I'm struggling to understand how a battery or cell is a source of potential difference. Is it because the cell or battery transfers electrical energy to the electrons each time they pass through?
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2 years ago
#2
Batteries (or cells) have + and - terminals which means that there will be potential difference.
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2 years ago
#3
(Original post by grace10101)
I understand that potential difference is the difference in energy across a component but I'm struggling to understand how a battery or cell is a source of potential difference. Is it because the cell or battery transfers electrical energy to the electrons each time they pass through?
You would normally say a battery or cell is a source of EMF, rather than potential difference. By that you are saying that the cell gives energy to the charges passing through it. The emf is measured in volts.
Potential difference is also measured in volts. It measures the energy (in joule) gained or lost by a charge (coulomb) passing through that potential difference.
The potential difference in the case of the cell, is a measure of the energy given to the charges. This comes from the chemical energy in the cell being converted to electrical. (In a dynamo it would be mechanical energy that was converted to electrical.)
When the charges flow round a circuit they lose energy. The potential difference between any 2 points in the circuit is a measure of how much electrical energy they have lost in moving between those 2 points.
In a circuit you have this process where the cell gives the charges electrical energy, and the cells lose this energy as they move round it. When they reach the cell again they get more energy and the process continues for as long as the cell can provide the energy. (Until the battery is 'flat'.)
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