Question

State whether True or False-
A relay is an electromagnetically controlled mechanical device in which electrical contacts are opened or closed by a magnetizing current.
A. True
B. False

Answer 1

Hint: A switch that connects or disconnects two circuits is also known as a relay.
Instead of manual operation, an electrical signal is used to activate a relay, which connects or disconnects another circuit.
Different types of relays exist, such as the electromechanical and solid-state. Relays that are electromechanical are often utilized.

Complete step-by-step solution:
To operate the switch permanently, latching relays only require a single pulse of control power. Resetting the switch requires another pulse applied to the second set of control terminals, or a pulse with the opposite polarity, whilst repeated pulses of the same kind have no impact.
The classic form of a relay relies on an electromagnet to shut or open the contacts, but various working principles have been developed, such as solid-state relays, which control without the use of moving elements.
To safeguard electrical circuits from overload or defects, Relays with calibrated operating characteristics and often several operational coils are employed; in current electric power systems, similar functions are fulfilled by digital instruments still referred to as protective relays.
Hence, option (A) is the correct answer.

Note:A simple electromagnetic relay is made up of a wire coil wrapped around a soft iron core (a solenoid), an iron yoke that offers a low resistance channel for magnetic flux, a moveable iron armature, and one or more sets of contacts (there are two contacts in the relay pictured).
The armature is mechanically connected to one or more sets of movable contacts and is hinged to the yoke. When the relay is de-energized, the armature is kept in place by a spring, creating an air gap in the magnetic circuit.
One of the two sets of contacts in the relay shown is closed, while the other is open in this scenario. Depending on their role, other relays may have more or fewer sets of connections.