The circuit board relay is a miniaturized electronic control device, in which the circuit board makes the circuit miniaturized and intuitive, and plays an important role in the mass production of fixed circuits and the optimization of the layout of electrical appliances. The relay has a control system (also known as an input circuit) and a controlled system (also known as an output circuit), and is usually used in an automatic control circuit. It is actually an "automatic switch" that uses a smaller current to control a larger current. Therefore, it plays the role of automatic adjustment, safety protection, and conversion circuit in the circuit.

1. Take out the 5-pin relay with a voltage of 12V;
2. Turn the relay over;
3. Then connect the positive and negative power supply pins to 12V DC according to the circuit diagram;
4. The middle pin of the three pins is the conduction pin, this is the soldering pin of the circuit we want to set on and off;
5. The two pins at the other end are "normally open" and "normally closed" pins;
6. Choose to use the "normally open normally closed" pin according to your needs. After turning on the 12V DC, you will hear the sound of the relay "clicking", indicating that it is working normally. Three pins are in a row, the first pin and the third pin are 12V coils, the middle pin is the common point of the contact, and the other two pins are on the same pin, one is a normally open point and the other is a normally closed point.