Types of voltage

Types of voltage

There are two types of energy transfers in

• When energy is ‘lost’ by a coulomb (i.e. ‘given’ to a component), it’s called ‘potential difference’.
• When energy is ‘gained’ by a coulomb (usually from a cell), it’s called ‘EMF’.

Potential difference

• Potential difference is the work done by unit charge.
• It’s a type of voltage that represents the energy transferred to or from a component in a circuit (not from the cell/battery).
• If the potential difference across a component is, for example, 6V, that menas that 1C of charge transfers 6J of energy to the component.
• It’s called the ‘potential difference’ because it is the difference in energy (work done) or volts across a component.
• Potential difference can be measured with a voltmeter.

Potential difference equation - work done and charge

\text{potential difference} = \frac{\text{work done}}{\text{charge}}

V=\frac WQ

Potential difference equation - current and resistance

\text{potential difference} = \text{current} \times \text{resistance}

V=IR