Question

What is the main purpose of Relay?

• A. To measure electrical resistance
• B. To filter electrical noise
• C. To amplify electrical signals
• D. To switch electrical circuits on and off

Hint:

Relays are "Electromechanical." If you hear a "click" when a device (like a heater or car blinker) turns on, that's usually the physical armature of a relay moving!

Answer 1

The Correct Option is D

1. How it Works: A typical electromagnetic relay contains a coil of wire. When current flows through this coil, it creates a magnetic field that pulls a metal armature. This armature then physically moves electrical contacts to either "Make" or "Break" an external circuit.

2. The Switching Function: The fundamental purpose is

switching. It allows you to:

• Turn on a heavy industrial motor using a tiny button.

• Control high-voltage AC using low-voltage DC from a computer.

• Automatically switch power sources in the event of a failure.

3. Addressing other options:

• Measurement: Done by Ohmmeters.

• Filtering: Done by capacitors, inductors, or electronic filters.

• Amplification: Relays can "amplify" in terms of power control, but they are binary (ON/OFF). Continuous signal amplification is the job of Transistors or Op-Amps.