What is the basic difference between a magnetic (proximity) switch and a temperature switch in control systems?

• A. It detects presence or proximity of a metal object without contact; a temperature switch responds to specific temperature thresholds to open or close contacts.
• B. A magnetic switch detects temperature changes; a temperature switch detects proximity to metal.
• C. A magnetic switch uses optical detection; a temperature switch uses humidity sensing.
• D. A magnetic switch requires continuous lubrication; a temperature switch is maintenance-free.

Answer: (C)

A magnetic (proximity) switch senses the presence or closeness of a metal object without making contact, typically using an inductive or magnetic field principle to actuate its contacts. A temperature switch changes its contact state when a specific temperature is reached, using a temperature-sensitive element like a bimetal strip to open or close the circuit. In practice, proximity switches are used to detect parts or objects nearby to control machinery, while temperature switches protect systems by responding to heat. The other options misstate how these devices sense: a magnetic proximity switch does not rely on optical detection, and a temperature switch does not sense humidity. So the first description accurately captures the difference.