Electromechanical Relay Explained

Electromechanical Relay Explained – A Fundamental Component in Automation

An electromechanical relay is an electrically operated switch used to control high-power circuits with low-power signals. It consists of a relay coil, a common contact (COM), a Normally Open (NO) contact, and a Normally Closed (NC) contact.

When the relay coil is energized, a magnetic field is generated that moves the relay armature, changing the contact position from NC to NO. This allows electrical isolation between the control circuit and the load circuit, making relays widely used in PLC panels, motor control circuits, protection systems, and industrial automation applications.

The circuit shown also includes a flywheel (freewheeling) diode across the relay coil. This diode protects the transistor and other electronic components from voltage spikes generated when the relay coil is switched OFF.

Understanding relay operation is essential for troubleshooting control panels, designing automation systems, and interpreting electrical schematics.