Relays are electromechanical or solid-state switching devices used to control high-power or high-voltage circuits using low-power control signals. They allow electrical isolation between control and load circuits, ensuring safe and reliable operation. Relays are commonly used to switch loads such as motors, lamps, heaters, and power lines in automation and control systems. Available in various types such as electromagnetic relays, solid-state relays, reed relays, and time-delay relays, they come with different contact configurations, coil voltages, and switching capacities. Relays are widely used in industrial automation, automotive systems, power equipment, consumer electronics, and protection circuits, contributing to system safety, flexibility, and dependable performance.