ECE 201 Circuit Theory I5 Plunger is extended by the force of the spring
ECE 201 Circuit Theory I6 Energized State Plunger is retracted
ECE 201 Circuit Theory I7 Both iron cores become magnetized, and the South pole of the stationary core attracts the North pole of the movable core, causing it to slide inward, retracting the plunger and compressing the spring. This happens as long as there is sufficient current. When the current is turned off, the magnetic fields collapse and the force of the spring pushes the plunger out.
ECE 201 Circuit Theory I8 Uses of Solenoids Provide movement –Door locks –Valves
ECE 201 Circuit Theory I9 Relays Used to open or close contacts (switches) Mechanical Relay