What is the principal use of a relay in electrical systems?

Relays are essential components in electrical systems that primarily function as automated switches. The principal use of a relay is to switch circuits on or off automatically based on specific conditions or signals. This capability allows for the control of larger electrical currents or voltages by using a low-power signal. When the relay receives the appropriate trigger, it opens or closes a circuit, enabling or disabling the flow of electricity.

This is particularly useful in various applications, such as controlling motors, lighting systems, or other devices where manual operation would be impractical or unsafe. The use of relays enhances automation and protection in electrical circuits, making them crucial in numerous systems, including industrial and residential setups.

Other options, while they describe important electrical functions, do not accurately capture the primary purpose of a relay. Storing electricity for later use pertains to batteries and capacitors, increasing voltage levels is related to transformers, and measuring electrical consumption falls under the role of ammeters or energy meters.