A power relay is an electromagnetic switch that is used to control high-power electrical circuits by using a low-power signal. The relay consists of a coil, contacts, and a switching mechanism. When a current flows through the coil, it generates a magnetic field that moves the switch's contacts, either closing or opening the circuit. This allows a small current to control a much larger current, thus providing a means to safely handle high-voltage equipment.

    There are two main types of power relays： mechanical relays and solid-state relays (SSRs). Mechanical relays have physical moving parts that open and close the circuit, while solid-state relays use semiconductor components to achieve the same result but with no moving parts. Both types serve similar purposes but have different characteristics in terms of performance, durability, and speed.