2.05 Comparison between gravitational and electrical potential

To understand what we mean by voltage and electrical potential let us consider a similar example.

crane 1        crane 2        crane 3
Consider an object which has been raised above the surface of the earth. If the object is released it will fall back towards the earth attracted by gravity. When the object is initially raised we provide it with energy (potential energy). When it falls this energy is released as it is converted to different forms.

crane 4
The higher the object is raised the more energy it will have to release when it falls.

crane 5
Also the more massive the object is the more energy it will have to released when it falls.
(We can appreciate either of the two previous facts by considering the damage that would be done when the object hits the ground.)

In comparison with the above example,

Electrical potential, potential difference (p.d.)

Electrical potential is a measure of the electrical potential energy supplied to each coulomb of charge by the battery. Electrical potential is measured in volts. A potential difference is just the difference in the electrical potential between two points in a circuit.

p.d. = W/Q