The Difference Between Solid-state Relays And Traditional Relays

Traditional relays are generally composed of relay coils and dynamic and static contacts, which utilize the electromagnetic attraction of the relay coil to operate and achieve the connection and disconnection of the circuit. Solid state relays do not have contacts, but rely on the electromagnetic and optical characteristics of semiconductor devices and electronic components to complete their isolation and relay switching functions.

The comparison between traditional relays and solid-state relays involves multiple types. Below is a comparison between electric relays and corresponding solid-state relays to illustrate their differences:

1. Structural difference: Electromagnetic relays operate by utilizing the suction force generated by the circuit in the input circuit between the electromagnetic iron core and the armature; Solid state relays use electronic components to perform their functions without mechanical moving components, and the inputs and outputs are isolated.

2. Differences in working methods: Electromagnetic relays use the principle of electromagnetic induction to control the circuit's opening and closing through the force of an electromagnet. Therefore, by using direct current to connect the coil, the contacts can be connected to AC or DC power; Solid state relays rely on the electrical, magnetic, and optical characteristics of semiconductor devices and electronic components to complete their isolation and relay switching functions. Therefore, they are divided into DC input AC output type, DC input branch output type, AC input AC output type, and AC input DC output type.

3. Difference in working status: Electromagnetic relays utilize the suction generated between the armature to turn on and off the circuit, resulting in slow response, noise, and limited lifespan; Solid state relays have fast response, noiseless operation, and long service life.

4. In terms of usage environment: temperature, humidity, atmospheric pressure (altitude), sand and dust pollution, chemical gases, and electromagnetic interference, electromagnetic relays are generally not as good as solid-state relays.

5. Electrical performance difference: Compared with corresponding solid-state relays, electromagnetic relays have simple driving, high power consumption, good isolation, and good short-term overload resistance. They are not as good as the latter in controlling high current and high-power situations, and have a longer lifespan when controlling circuits with complex actions.