In electrical terms, what does a switch do?

A switch in electrical terms functions as a device that controls the flow of electric current within a circuit. When a switch is in the 'on' position, it closes the circuit, allowing current to flow freely from the power source to the load (such as a light bulb), thus enabling the electrical device to operate. Conversely, when the switch is turned 'off,' it opens the circuit, stopping the flow of current and turning off the device.

This functionality is essential for controlling electrical appliances safely and conveniently. For example, light switches allow you to turn lights on or off without needing to manipulate wiring, which could be dangerous.

In contrast, other options relate to different electrical concepts. Increasing current refers to the effect of resistance and voltage, while decreasing voltage pertains to the use of transformers or resistors. The conversion from AC to DC is a function of rectifiers and not related to the operational function of a simple switch. Therefore, the correct option highlights the role of a switch in managing electrical current flow within a circuit.