16 Channel 5V 12V Relay Module Relay Control Board with Optocoupler Protection and LM2576 Power Supply

12V relay contact capacity 10A 250V, with optocoupler protection. 5V drive. Support all SCM driven. The onboard power module does not require an external power supply. I/0 port drive is active low.

The working principle of the relay: As long as a certain voltage is applied to both ends of the coil, a certain current will flow through the coil, which will produce an electromagnetic effect. Under the action of electromagnetic force, the armature will overcome the pulling force of the return spring and attract to the iron 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 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 "normally open contact"; the static contact that is in the on state is called It is "normally closed contact". Relays generally have two circuits, a low-voltage control circuit and a high-voltage working circuit.

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