What role does a touch sensor play in a circuit?

A touch sensor serves as a crucial control interface in a circuit by detecting physical contact and responding to it. When someone touches the sensor, it can change the output voltage, signaling to other components in the circuit to perform specific actions. This capability makes touch sensors particularly valuable in applications such as consumer electronics, where user interaction starts various processes or functions.

In comparison, measuring temperature changes is not a function of a touch sensor; that role is typically fulfilled by thermistors or thermocouples. Regulating a power supply is usually carried out by voltage regulators, which maintain a constant output voltage despite variations in input voltage or load conditions. Dividing power supply voltage is the function of a voltage divider, typically involving resistors arranged in a specific manner to achieve the desired voltage levels. Thus, the unique ability of a touch sensor to change output voltage in response to touch identifies it as the key correct answer in this context.