Abstract: To increase the output amplitude obtained from Wiegand wire transducers, for example of the type used in contactless ignition breaker systems, a flux concentration or flux guide element (3) of highly permeable material, for example high-frequency ferrite core material, is provided surrounding the Wiegand wire (1) and, at least in part, the pick-up coil (2) coupled thereto.

Abstract: To provide bipolar needle pulses in which oppositely polarized pulses occur close together to form pulse pairs, with long time intervals between pulse pairs, a pair of pole disks (10, 11) are located on a rotor (91, 12) with a permanent magnet (13) interposed. The disks have radially and axially extending claws (15a, 15b, 16) formed thereon, the axial extensions being directed towards each other, but the claws (15a, 15b) projecting from one disk (10) being arranged in claw element pairs with which the claws (16) from the other disk, and magnetically oppositely polarized, are interdigited. The magnetic field, passing through the air gap between the claws, is sensed by a stationary pick-up such as a Hall sensor, a Wiegand sensor, or a magnetic field plate. When used for ignition timing of an internal combustion engine, the number of interdigited claws may correspond to the number of cylinders, and the claw pairs are spaced closely together so that the time (t.sub.

Abstract: To simplify a Wiegand wire type pulse source, a Wiegand wire (4) has a coil (3) wound thereon. A permanent magnet (5) is positioned with a gap from the coil, and a magnetically permeable masking element, for example a sector-shaped disk, is movable between the magnet and the coil. The coil (3) is connected to a source of direct current (B) which so magnetizes the Wiegand wire (4) that, when a gap of the masking element occurs between the magnet (5) and the coil (3), the Wiegand wire is reversely magnetized until, again, a solid portion of the masking element is interposed in the gap between magnet (5) and coil (3) to restore the magnetic direction due to the battery (B). Re-magnetization pulses are picked off the coil (3) by a suitable pulse coupling element such as a capacitor (C).