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How a relay works

Model: (Various brands) Various
Part: Fuse box

Video tutorial

The relay is an electric switch, and it is the simplest way to allow a low-power circuit to control the on and off operation of a high-power circuit. Its function is to physically and electrically separate the two circuits.

The relay shown in the video is monostable, meaning it remains "energized" only as long as the coil is powered, and it consists of two distinct parts: the control circuit, which is a coil of copper wire wound around a core of iron. When a voltage is applied to its terminals, the coil becomes "energized," and the electricity flowing through the coil generates a magnetic field, turning it into a magnet.

The power circuit, on the other hand, consists of a movable metal armature, a spring, and fixed contacts. When the coil is not powered, the spring holds the armature up, interrupting the circuit.

When the coil is powered, the magnetic field generated by the coil pulls the armature down, closing the contact, and current can flow.


Posted on 19 December 2025 by ScegliAuto


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by ScegliAuto

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