All electronic sensors consists of two major components: a sensor and a(n) ______.

• A. Transmitter
• B. Amplifier
• C. Power supply
• D. Switch

Answer: (D)

A sensor is about turning a physical thing into an electrical signal that a control system can use, and in many electronic sensors the way this signal is presented is as a simple on/off state. That’s achieved with a switch built into the sensor. The sensing element detects the condition (like presence, position, or level) and the switch changes state when that condition occurs, giving a clean binary output that can drive logic, PLCs, or relays. While some sensors include extra stages such as a transmitter or amplifier, those are enhancements rather than the fundamental two parts that define a basic sensor in this context. The switch provides the direct, easily used interface to the rest of the system.