On an electronic oil safety switch, what changes the pressure signal to an electrical signal?

• A. Sensor
• B. Transmitter
• C. Gauge
• D. Transducer

Answer: (D)

Pressure is a mechanical quantity, and the control electronics need an electrical signal to read it. A transducer is the device that makes that happen: it converts the physical pressure into a proportional electrical output (voltage or current) that the safety switch can process. The other parts have different roles: a gauge displays the pressure but doesn’t produce an electrical signal; a sensor detects pressure but the act of turning that measurement into an electrical signal is done by the transducer; a transmitter takes an electrical signal and sends or conditions it for remote monitoring, rather than creating the signal from scratch.