Electromagnetic actuator with movable coil and position sensor for drive coil

An electromagnetic actuator with position sensor, comprising:

• a core made of a soft magnetic material;
• a permanent magnet located adjacent and fixed relative to a first portion of the core for providing a magnetic field in the core;
• an electrically conductive drive coil wrapped about a second portion of the core, the second portion having a cross-section which changes along a length of the second portion;
• means for supporting the drive coil such that the drive coil can move along the second portion of the core;
• and
• an electrically conductive sense coil wrapped about a third portion of the core and fixed relative to the core such that there is substantially no relative movement between the sense coil and the core,
• such that when an electrical current is passed through the drive coil, the drive coil moves along the second portion of the core and an electrical current is induced in the sense coil which indicates the position of the drive coil relative to the second portion of the core.