A relay mainly consists of two important components — the electromagnet (coil) and the contacts. These two parts work together to control the switching operation inside the relay.
The electromagnet, also called the coil, is the heart of the relay. It is made of a coil of wire wound around a metal core. When a small control voltage is applied to this coil, it creates a magnetic field. This magnetic field pulls a movable part of the relay called the armature, which then changes the position of the contacts. The strength of the magnetic field depends on the amount of current flowing through the coil. When the current stops, the magnetic field disappears, and a spring returns the armature to its original position.
The contacts are the parts of the relay that open or close the circuit. They act like a switch controlled by the electromagnet. When the coil is energized, the armature moves and either connects or disconnects the contacts, allowing current to flow or stop in the output circuit. There are two basic types of contacts — Normally Open (NO) and Normally Closed (NC). In a Normally Open relay, the contacts close when the coil is energized, while in a Normally Closed relay, the contacts open when the coil is energized.
Together, the coil and the contacts make the relay work. The coil controls the magnetic action, and the contacts handle the switching of power in the circuit.
Relays from brands like Omron use these two components in highly efficient designs to achieve fast, reliable, and safe switching. Whether in control panels, automation systems, or protection circuits, these two parts — the electromagnet and the contacts — are what make every relay function effectively.