摘要 |
For generating control pulses for timing gasoline engine ignition, a rotor of magnetically conducting material with one or more notches in its edge cooperates with a stator also of magnetically conducting material having the configuration of a shallow U, of which the extremity of one leg presents a broad area to the narrow air gap between it and the edge of the rotor and the other leg presents essentially a knife edge. A magnet is mounted on the former leg and a pick-up device, such as a Hall generator, field plate, inductive winding or a reed switch is provided on the other leg to produce an electric signal in response to changes in magnetic flux. The passage of the notch by the broad area foot of the stator produces at most an insignificant change in flux, whereas passage of the notch by the other stator leg produces a sharp change in flux and hence a control pulse. |