The ___________ part of a pressure sensor converts the movement of mechanical elements into an electrical signal.

• A. Actuator
• B. Amplifier
• C. Sensor
• D. Transducer

Answer: (D)

The key idea is transduction: converting one form of energy into another. In a pressure sensor, the mechanical movement caused by pressure (the diaphragm deflection or element strain) is transformed into an electrical signal by the transducing element. This could be a strain gauge, piezoresistive element, or capacitive/other sensor that changes resistance, capacitance, or voltage in response to the mechanical movement. An actuator is the opposite—it uses electrical energy to create motion. An amplifier only boosts an existing electrical signal, and a sensor detects a physical quantity but doesn’t necessarily convert the movement into an electrical signal by itself. So the part that performs the conversion from mechanical movement to an electrical signal is the transducer.