The miniature power relay is a small electronic control device that is co-powered by DC current. With a control system (also known as input circuit) and a control system (also known as output circuit), usually used in automatic control circuits. It is equivalent to an “automatic switch”, which plays a role in the circuit as an automatic adjustment, safety protection, conversion circuit, etc.
As long as a certain voltage is applied at both ends of the power relay’s coil, a certain current will flow through the coil, thus creating an electromagnetic effect, and the armature will overcome the pull of the return spring to the core under the action of electromagnetic attraction, thus, the moving contact of the armature is driven to engage with the static contact (normally open contact) .
When the power relay’s coil is turned off, the magnetic attraction disappears, and the armature returns to its original position in the reaction of the spring, causing the moving contact to engage with the original static contact (normally closed contact) . In this way, suction, release, so as to achieve in the circuit of conduction, cut-off purposes. For the power relay “normally open, normally closed” contacts, can be distinguished as follows: The power relay’s coil is not power on the state of the static contact, known as the “normally open contact”.