Electromechanical relays (EMRs) are switching devices that use an electromagnetic coil to mechanically open or close electrical contacts. When current flows through the coil, it generates a magnetic field that moves an armature, either completing or breaking a circuit. EMRs are widely used for controlling high-power loads with low-power control signals in industrial automation, HVAC systems, motor controls, and safety circuits. Known for their simplicity, electrical isolation, and ability to handle large currents and voltages, EMRs remain a reliable solution for applications where physical switching and clear on/off states are required.