While the actuation system, mechanical construction and the function as a whole do indeed differ, fundamental elements of the actuator are identical on virtually all actuation principles. The core of a solenoid consists of an electrical magnet, which is also referred to as a solenoid coil.
If an electric current flows through an electrical conductor, e.g. an enameled copper wire, this wire also generates a magnetic field. This magnetic field can be amplified by focusing the electrical conductors in the form of a coil. In addition to the number of windings and the amperage, the iron circuit around the solenoid coil also has a substantial impact on the resultant magnetic forces. Normally, the polarity does not need to be noted.