Solenoids are essentially a switch that enables electrical current to flow and power up a load. Generally, though, a solenoid does a bit more than this as they enable moving parts to be engaged automatically rather than manually.
For example, the starter motor is activated by a solenoid to engage the flywheel and turn the engine over. That's why cars no longer have starting handles.
A solenoid is basically an electromagnetic coil that is wrapped around a moveable iron core or plunger. When electrical current is applied to the coil, an electromagnetic field is produced in the core or plunger. Magnetic attraction causes the core or plunger to be pulled into the centre of the coil. It is this movement towards the centre of the coil that activates the load by, for example, closing contacts to enable a large electrical current to flow to the load.
When electrical current to the coil is shut off, the electromagnetic field stops and the moveable core returns to its original position off centre, either by means of a strong return spring or by a secondary winding designed to uncentre the cored.
For example, the starter motor is activated by a solenoid to engage the flywheel and turn the engine over. That's why cars no longer have starting handles.
A solenoid is basically an electromagnetic coil that is wrapped around a moveable iron core or plunger. When electrical current is applied to the coil, an electromagnetic field is produced in the core or plunger. Magnetic attraction causes the core or plunger to be pulled into the centre of the coil. It is this movement towards the centre of the coil that activates the load by, for example, closing contacts to enable a large electrical current to flow to the load.
When electrical current to the coil is shut off, the electromagnetic field stops and the moveable core returns to its original position off centre, either by means of a strong return spring or by a secondary winding designed to uncentre the cored.
