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Question

Difficulty: EasySwitches and Relays

In an electromechanical relay, which internal component creates the magnetic field needed to pull the movable armature and actuate the electrical contacts?

  1. A
    A thermal bimetallic strip
  2. An electromagnetic wire coilAnswer
  3. C
    A dielectric ceramic barrier
  4. D
    An electrostatic storage plate

Answer

An electromagnetic wire coil creates the magnetic field that pulls the armature to actuate the contacts in an electromechanical relay.
An electromechanical relay consists of an insulated wire coil wound around a ferromagnetic core. When a control current passes through this coil, it produces an electromagnetic field that pulls the hinged iron armature, physically shifting the contact positions to open or close the circuit.

Step-by-Step Solution

1
Identify the operating mechanism of an electromechanical relay.
An electromechanical relay uses an electrical control signal to produce mechanical motion via magnetic force.
Relays use electromagnetism to allow a low-power circuit to open or close a separate electrical circuit.
2
Determine which component generates the magnetic force within the relay.
An insulated wire wrapped around an iron core forms an electromagnetic coil that produces magnetic flux when energized.
When current flows through the coil, the resulting magnetic attraction pulls the movable iron armature toward the core, changing the position of the contacts.

Key Concept

Electromechanical relay coil operation and magnetic contact actuation
Estimated Time:45s
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Topics

Switches and Relays

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