1. According to the working principle or structural characteristics of the relay 1) Electromagnetic relay: An electrical relay that works by the suction force generated between the electromagnet core and the armature by the circuit inside the input circuit. 2) Solid state relay: A type of relay in which the electronic component performs its function without mechanical moving parts, and the input and output are isolated. 3) Temperature relay: A relay that operates when the outside temperature reaches a given value. 4) Reed relay: a relay that opens, closes or switches the line by using a reed action that is sealed in the tube and has the dual action of the electric spring and the armature magnetic circuit. 5) Time relay: When adding or removing the input signal, the output part needs to delay or limit the time to close or open its controlled line relay until the specified time. 6) High-frequency relay: A relay used to switch high-frequency, RF lines with minimal loss. 7) Polarized relay: A relay that has a polarized magnetic field and a control action that operates in conjunction with a magnetic field generated by a control coil. The direction of operation of the relay depends on the direction of the current flowing through the control coil. 8) Other types of relays: such as optical relays, acoustic relays, thermal relays, instrumentation relays, Hall effect relays, differential relays, etc. 2, according to the size of the relay 1) Micro relay 2) Ultra-small miniature relay 3) Small miniature relay Note: For sealed or enclosed relays, the dimensions are the maximum dimensions of the relay body in three mutually perpendicular directions, excluding the dimensions of the mounting, extraction, rib, crimp, flange and seal welds. 3, according to the load classification of the relay 1) Micro power relay 2) weak power relay 3) Medium power relay 4) High power relay 4, according to the protective characteristics of the relay 1) Sealed relay 2) Closed relay 3) Open relay 5, according to the relay according to the principle of action can be classified 1) Electromagnetic type 2) Inductive type 3) Rectified type 4) Electronic type 5) Digital type, etc. 6, according to the physical quantity of the reaction can be classified 1) Current relay 2) Voltage relay 3) Power direction relay 4) Impedance relay 5) Frequency relay 6) Gas (gas) relay 7, according to the role of relays in the protection circuit can be classified 1) Start relay 2) Measurement relay 3) Time relay 4) Intermediate relay 5) Signal relay 6) Exit relay color difference,Paint colorimeter,Textile colorimeter CHNSpec Technology (Zhejiang)Co.,Ltd , http://www.chnspec.xyz