Automotive PCB relay products are mainly composed of coils, armatures, moving contacts and static contacts. When the current passes through the coil, a magnetic field is generated, attracting the moving contact to move, and contacting the static contact, so that the terminal 1 and the terminal 2 are connected, so the main circuit forms a loop, so that the controlled electrical appliances are put into operation. It can be seen that the circuit of pcb relay products actually includes two parts: the control circuit operated by the coil and the main circuit operated by the contact. The pair of contacts in the main circuit can only act when there is working current flowing through the relay coil.

The number and functions of pcb relay products will not be the same for different models; generally in the domestic market, the number of pcb relay products in the models that are often seen is about 20-40; not only on cars, but on any equipment In the electronic circuit of the facility, the role of the relay is to use a small voltage or a small current to control a large current or a high voltage; but it does not have the effect of increasing the current or voltage; what it plays The function is the function of a switch; under the control of low current or low voltage, the other pair (or several pairs) of relatively large contacts are connected (or disconnected). Inside the relay, the term is called normally closed and normally open. Contact); the purpose is to allow high current or high voltage to drive the load behind. This is the main function of pcb relay products; other functions:

 1. Isolation (mainly refers to strong and weak current, or AC or DC);
 2. Protection; for example, when the monitor (high-end) displays images, the output of the audio power amplifier is connected to the speaker (horn), the relay is used;
 3. Step-by-step conversion; in electronic circuits, sometimes the controlled voltage or current is relatively high or large, and the first-level relay cannot be completed, then several levels of pcb relay products must be used to make the transition.