Abstract: An induction device comprises a winding support with a base having connection points. The upper side of the base carries a centering member having an exterior surface that defines either a cylindrical or conical surface co-axial with the cylindrical central portion of a core. A winding is provided about the central portion of the core. The core has a non-circumferentially or rotationally symmetrical upper flange. A ferromagnetic adjusting core in a form of a cap is arranged over the core that carries the coil, the portion of the cap facing the base having internally a shape a radial dimensions corresponding to the cylindrical or conical surface of the centering member. The cap encloses the centering member with a close fit, so that the adjusting core is rotatable about the axis of the core that carries a winding. The portion of the adjusting core adjacent to the upper flange portion of the core that carries a winding is also non-circumferentially (i.e., rotationally) symmetrical.

Abstract: The coil comprises a coil former with a rod-shaped central core portion (1) and two end portions (3,5) wherebetween a winding (13) made of a conductor (15) is provided. No part of the coil projects beyond a first boundary plane which contains an outer surface (25) of the first end portion (3) and preferably also a contact surface (21, 23) and which encloses an angle of between 5.degree. and 85.degree. with respect to the axis (11) of the rod-shaped central portion. The mutual coupling of two or such coils can be very readily varied by mounting the coils in the same position or rotated through 90.degree. or 180.degree. with respect to respect to each other on a substrate (27).