A timer relay is a combination of an electromechanical output relay and a control circuit the contacts will open or close before or after a preselected timed interval.
what is an 8 pin relay
the relay works on the principle of electromagnetic force when the coil is energized it becomes magnetized in an 8 pin relay as shown here there are 2 common contacts 2 normally open contacts and 2 normally closed contacts relays control one electrical circuit by opening and closing contacts in another circuit.

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