What is the purpose of a switch in an electrical circuit?

The purpose of a switch in an electrical circuit is to make, break, or change connections in the circuit. This function allows for the control of the flow of electricity. When the switch is in the "on" position, it completes the circuit, enabling current to flow to devices such as lights or appliances. Conversely, when the switch is in the "off" position, it opens the circuit, stopping the flow of electricity. This capability is crucial for managing electrical power, allowing users to turn devices on and off without having to disconnect wiring or power sources directly.

The other options provided don't accurately describe the function of a switch. Increasing voltage is typically achieved through transformers or other electrical components, while measuring current usually requires a device such as an ammeter. Energy storage is performed by components like batteries or capacitors, not switches. Thus, the role of a switch fundamentally revolves around its ability to control connections within a circuit.