Working principle of electromagnetic relay
Electromagnetic relays are generally composed of electromagnets, armatures, springs, contacts, etc., and their working circuits are composed of low-voltage control circuits and high-voltage working circuits. The electromagnetic relay can also realize remote control and automatic control. As long as a certain voltage is applied to both ends of the coil, a certain current will flow through the coil, thereby generating electromagnetic effects, and the armature will attract the iron core against the pulling force of the return spring under the action of electromagnetic force attraction, thereby driving the armature. The moving contact and the static contact (normally open contact) attract.
When the coil is de-energized, the electromagnetic suction will also disappear, and the armature will return to the original position under the reaction force of the spring, so that the moving contact and the original static contact (normally closed contact) are released. This pulls in and releases, thus achieving the purpose of turning on and off in the circuit. The "normally open, normally closed" contacts of the relay can be distinguished in this way: the static contacts that are in the off state when the relay coil is not energized are called "normally open contacts"; the static contacts in the on state are called It is "normally closed contact". The wiring method of the electromagnetic relay is shown in the figure below.