How to choose relays correctly? One is to achieve the goal of "knowing what is known", which means that the first step is to carefully investigate and thoroughly understand the nature, characteristics, and requirements of each controlled circuit controlled by the relay.

Secondly, comprehensively grasp and carefully analyze the various characteristics of the relay itself, including principles, usage conditions, skill parameters, structural and technological features, as well as specifications and models; Second, according to the principle of "value engineering", relay shall be correctly selected and used in consideration of progressiveness, rationality, availability and economy.

The specific criteria for selecting relays correctly should be:

(1) The main skill performance of relays, such as contact load, action time parameters, mechanical and electrical lifespan, should meet the requirements of the entire system;

(2) The structural type (including installation method) and external dimensions of the relay should be suitable for the needs of the usage conditions;

(3) Economically reasonable.

Usually used in automation control circuits, it is actually an "automatic switch" that uses low current to control high current operation. Therefore, it plays a role in automatic regulation, safety protection, and circuit conversion in the circuit. The above three points are the general criteria for selecting universal relays.