How does weak current control strong current and how to connect it?

The method of controlling strong current by weak current: using power control devices, such as silicon controlled rectifier, power transistor, power MOS tube, power tube, etc., which are characterized by low input control signal power but high output control power. In this way, strong current can be controlled by weak current.

this is controlled by a relay. When the weak current switch is closed, a current is generated in the circuit, and the current generates magnetic induction through the relay coil, which sucks down the strong current switch and closes the strong current circuit.

Extended information:

Strong current and weak current are relative concepts. Conceptually, the main difference is the difference in use, and the relationship between them cannot be defined simply by the voltage.

There are both connections and differences between them. The general principle of distinction is that the object of strong electricity is energy (electricity), which is characterized by high voltage, high current, high power and low frequency.

the main consideration is to reduce the loss and improve the efficiency. The weak current mainly deals with information, that is, information transmission and control, which is characterized by low voltage, low current, low power and high frequency. The main consideration is the effect of information transmission, such as fidelity, speed, breadth and reliability of information transmission.

Reference: Baidu Encyclopedia-Weak current

Reference: Baidu Encyclopedia-Strong current.