4 pin relay is generally composed of iron core, coil, armature, contact reed, etc. As long as a certain voltage is applied to both ends of the coil, a certain current will flow in the coil, which will produce electromagnetic effects. Under the action of electromagnetic force, the armature will overcome the pull force of the return spring and attract to the core, thereby driving the armature. The moving contact and the static contact (normally open contact) are pulled together. When the coil is de-energized, the electromagnetic attraction will disappear, and the armature will return to its original position under the reaction force of the spring, releasing the moving contact and the original static contact (normally closed contact).

This pulls in and releases, so as to achieve the purpose of conducting and cutting off in the circuit. For the "normally open and normally closed" contacts of the 4 pin relay, it can be distinguished as follows: the static contact that is in the off state when the relay coil is not energized is called the "normally open contact"; the static contact that is in the on state The points are called "normally closed contacts". The 4 pin relay generally has two circuits, a low-voltage control circuit and a high-voltage working circuit. Two pins of 4 pin relay85.86 are small current and small magnetic attraction, and the other two pins are connected to high current line.

The numbers of the 4 pin relay are 30 87 85 86, 85 and 86 set of pins are on the same coil, then connect 85 to the positive, 86 and 30 to ground, and 87 to the motor line of the box, but the box encountered is open The control lines are all positive electricity, and there is no negative electricity. If you control the positive electricity, you don't need to add a relay to convert it. If it is negative electricity, you need to do the above method. The very simple 5 pin relay is also connected in the same way. 87a does not need to be connected. OK.