The energy transferred when electric charge flows through a component (or device), depends on the amount of charge that passes and the potential difference across the component.
The power rating (in watts, W) of an electrical device is a measure of the rate at which an electrical power supply transfers energy to the device and/or its surroundings.
The rate of energy transfer depends on both the potential difference and the current.
The greater the potential difference, the faster the charges move through the circuit, and the more energy each charge transfers.
The National Grid uses transformers to step down the current for power transmission. The power output from a transformer cannot be greater than the power input, therefore if the current increases, the potential difference must decrease.
Transmitting power with a lower current through the cables results in less power being dissipated during transmission. |