According to the working principle or structural characteristics of the relay, there are thirteen types, namely: electromagnetic relay, solid state relay, temperature relay, reed relay, time relay, high frequency relay, polarization relay, photorelay, acoustic relay, thermal relay, Instrument relays, Hall effect relays, differential relays.
1. Electromagnetic relay: An electrical relay that works by using the suction effect generated between the electromagnet core and the armature by the current in the input circuit.
2. Solid state relay: refers to a relay in which the electronic components perform their functions without mechanical moving components, and the input and output are isolated.
3. Temperature relay: a relay that operates when the external temperature reaches a given value.
4. Reed relay: A relay that opens, closes or switches circuits by using the reed action that is sealed in the tube and has the dual functions of electric shock reed and armature magnetic circuit.
5. Time relay: When the input signal is added or removed, the output part needs to be delayed or limited to the specified time before closing or disconnecting the controlled circuit relay.
6. High-frequency relay: a relay used to switch high-frequency and radio-frequency lines with minimal loss.
7. Polarization relay: a relay that operates with the combined action of the polarized magnetic field and the control current through the magnetic field generated by the control coil. The direction of action of the relay depends on the direction of current flowing through the control coil.
8. Other types of relays: such as optical relays, acoustic relays, thermal relays, instrument relays, Hall effect relays, differential relays.
As a control element, the relay has the following functions in summary:
1. Expand the control range: For example, when the control signal of the multi-contact relay reaches a certain value, it can switch, break, and connect multiple circuits at the same time according to the different forms of the contact group.
2. Amplification: For example, sensitive relays, intermediate relays, etc., can control large-power circuits with a very small control amount.
3. Integrated signal: For example, when multiple control signals are input into the multi-winding relay in the prescribed form, after comparison and synthesis, the predetermined control effect is achieved.
4. Automatic, remote control, monitoring: For example, the relay on the automatic device and other electrical appliances can form a program control circuit to realize automatic operation.
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