How does sensor control a switch?

A sensor controls a switch by detecting specific environmental conditions, such as motion, temperature, or light. When the sensor detects a change that meets its threshold criteria, it sends a signal to the switch, which can then either open or close a circuit. This action allows the switch to control electrical devices, turning them on or off based on the sensor's input. For example, a motion sensor can activate a light switch when movement is detected in a room.