GB956499A - Improvements in or relating to magneto ignition systems - Google Patents

Abstract

956,499. Semi-conductor pulse circuits. BENDIX CORPORATION. Dec. 5, 1961 [Dec. 5, 1960], No. 43517/61. Heading H3T. [Also in Division F1] A transistorized ignition pulse generator comprises a transformer having a magnetic core and a magnetized rotor generating alternating current in the primary winding of the transformer. Assume that the rotor 13 is in such a position relative to the core 14 that the flux through the core has reached a maximum and has started to decrease whereby 22 is slightly positive. This makes the emitter 34 of the transistor 32 positive with respect to the base 31 so that transistor 32 is turned on. Therefore increased current now flows from the emitter to the collector 42 of the transistor 32 through collector 44 to base 37 of transistor 39 through winding 27 and through winding 11. By transformer feed-back action in coil 26 the current flow through the winding 27 causes a current flow in the winding 25 thus further increasing the base drive of transistor 32 still further causing the circuit to approach a shortcircuit on the winding 11 of the magneto. When the current reaches its peak value or when the transformer saturates the base drive voltage of the winding 25 reverses its polarity thereby causing the transistor 32 to turn off. This interrupts the current flowing through the primary winding 11 thereby inducing a voltage in the secondary winding 12. A similar cycle occurs when the rotor causes 24 to become positive. Should it be desired to utilize only one half of the flux reversals through the core 14 one of the transistors 32 and 39 may be omitted.