Relay components consist of an electromagnet, a set of contacts, and a spring mechanism. When an electrical current flows through the coil (electromagnet), it generates a magnetic field that activates the switch. This switch either opens or closes the relay contacts, allowing control over the larger circuit. Relays can be classified into various types, including electromechanical relays, solid-state relays, and hybrid relays, depending on the operating principles and the design. The choice of relay depends on factors such as switching speed, voltage, current handling capacity, and environmental conditions.