| 摘要 |
<p>1,234,574. Electrical signal transducers. ROBERT BOSCH G.m.b.H. Aug. 2, 1968 [Aug. 12, 1967], No. 36903/68. Heading G1N. [Also in Division H1] Apparatus for producing an alternating signal whose frequency is proportional to the speed of rotation of a shaft 13 Fig. 1 comprises an armature 12, with four equi-spaced poles 14, attached to the shaft, and located at one end of a longitudinally magnetized cylindrical magnet 11, flux from the other pole of the magnet being conveyed via plate 18 to a fixed yoke 19 also with four poles 15. Plate 18 and yoke 19 have matching projections 20, 21 between which is located a magnetosensitive semi-conductor element 17. When shaft 13 and armature 12 are rotating, the flux through element 17 is maximum each time the poles 14, 15 are in line, giving a large change in resistance which may be used to produce a corresponding change in voltage for initiating a cyclic switching action, e.g. for the ignition system of an I. C. engine. An alternative flux path is provided by a cup 24 and poles 23 to minimize flux leakage effects. The element 17 could alternatively be a Hall plate element.</p> |
