Relays are electronically operated switches. Which option best describes a relay?

• A. Electronically operated switches
• B. Mechanical timers
• C. Passive resistors
• D. Capacitors

Answer: (A)

Relays are devices that perform switching action driven by electricity. The key idea is that the control side uses an electric current to energize a coil, which creates a magnetic field that moves contacts to open or close a circuit on the load side. This makes the relay an electronically operated switch, allowing a small control signal to switch a larger load current and providing isolation between the control and the load. The other options don’t fit because a mechanical timer is about timing the switch action, a passive resistor simply resists current without switching, and a capacitor stores energy rather than performing the switching function.