Electrical Relay is an automatic control element with isolation switch function, which is widely used in electronic equipment such as remote control, monitoring, communication, electromechanical integration and so on. It can generally reflect a certain input variable (such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light, etc.) sensing mechanism (input part); automatic control on-off (output part); between the input part and output part of the relay, there is also an intermediate mechanism (drive part) for coupling and isolating the input, functional processing and driving the output part.
Fig 1. Common Electrical Relay Structure