| 摘要 |
PURPOSE:To prevent the generation of noises by a method wherein a pair of photosensors each comprising a photo-emissive element and a photo-receiving element are made integral with a unit comprising a control section and a switching section so that no space for mounting a photosensor and the circuit and no intermediate wiring is required. CONSTITUTION:A photo-diode 2a generates a pulsating signal in correspondence to the output circuit 20a of an oscillator 20. Even in case no incident light flux L2 on a photo-transistor 4a from a projection 3f of an object to be detected 3 is absent, a synchronous signal 20b is transmitted from the oscillator 20 to a synchronous detector 21. Next, when the object 3 to be detected is rotated to come to a position at which the effective light flux L2 becomes incident on the transistor 4a, a detecting signal is transmitted from the photo-receiving section 4, demodulated by the synchronous signal 20b, inputted to a next stage integrator 22, integrated every time when the detecting output is inputted to the integrator and finally becomes zero when no more detecting output is inputted. Such integrated output is received by a waveform shaping section 23 and when it is higher than a regulated level, an ignition coil 8 is energized. |
