Electromagnetic relays — identifying the moving part: In an electromechanical relay used in electronics and control circuits, which component is the primary movable element that shifts position when the coil is energized to open or close contacts?

Introduction / Context:
Relays are widely used to isolate control signals from power circuits, to switch loads, and to implement interlocks. Understanding the internal construction helps technicians diagnose failures and select appropriate parts. A key element is the component that physically moves when the coil is energized.

Given Data / Assumptions:

• We are discussing a conventional electromagnetic relay.
• A coil creates a magnetic field when energized by current.
• Mechanical contacts change state due to a movable piece attracted by the magnetic field.

Concept / Approach:
When the relay coil is energized, magnetic flux is produced in the iron core. This flux attracts a pivoted or spring-loaded movable piece called the armature. The armature motion opens or closes the relay contacts (such as SPDT or DPDT). Some relay designs include a plunger-type mechanism, but in standard terminology the main movable member in many relays is still referred to as the armature that actuates contacts.

Step-by-Step Solution:

Verification / Alternative check:
Exploded diagrams and datasheets for electromagnetic relays label the moving member as the armature, while the stationary piece is the yoke/core. Plunger styles are a subtype, but the moving magnetic element is still categorized as an armature assembly driving contacts.

Why Other Options Are Wrong:

• Plunger: A plunger is a specific mechanical style often used in solenoids; in relay terminology, the general movable member that operates contacts is the armature.
• Cone: Not a standard relay part.
• Brushes: Found in motors and generators, not in typical sealed relays.

Common Pitfalls:
Confusing solenoid plungers with relay armatures; assuming “armature” only applies to motors. In relays, armature denotes the moving magnetic element that actuates contacts.

Final Answer:
armature