Relay is an automatic switching element with isolation function, which is widely used in remote control, telemetry, communication, automatic control, electromechanical integration and power electronic equipment, and is one of the most important controlling components.
Relays generally have the ability to reflect certain input variables such as current, voltage, power, impedance, frequency, temperature, pressure, speed, light and so on, the induction mechanism (input part), there is the control circuit to achieve "pass", "broken" controller (output part); Between the input part and the output part of the relay, There is also an intermediate mechanism (drive part) for coupling isolation, function processing and actuation of the output part.
As a control element, as a general rule, relays have several functions as follows:
1. Enlarge the control range: for example, when the control signal of the multi-touch relay reaches a certain value, it can be changed in different forms of the Contact group at the same time.
2. Amplification: For example, sensitive relays, intermediate relays, and so on, with a very small amount of control, can control very high-power circuit.
3. Integrated signal: For example, when multiple control signals in the form of the input of multiple winding relays, after a relatively comprehensive, to achieve the desired control effect.
4. Automatic, remote control, monitoring: for example, a relay on an automatic device, along with other electrical appliances, can be programmed into a program-controlled circuit to automate the operation.