| 摘要 |
PURPOSE:To realize a device to increase the peak value of the optical pulse by receiving only the plus or minus AC power source by the projector and through the half-wave rectifier and also providing the means to give the driving and light projection to the luminous element in the fixed timing of the next antiphase half-wave of the AC power source. CONSTITUTION:Projector 1 consists of half-wave rectifier 105, the circuit connecting PUT29, coil 21 and light emitting diode 8 in series, resistances 101 and 102, capacitor 30 and diode 28 each. Capacitor 30 is connected across resistance 25, and light receiver 2 contains light reception element 9 and the like. Such AC 3-wire transmission type photoelectric switch drives once luminous element 8 of the projector every cycle of the AC power source to give the light emission, and also can set the discharging timing to the early time of the next half-cycle rise of the charging half-cycle via the instantaneous discharge current for the capacitor which is charged up to the driving current by using the half cycle of the AC power source. As a result, the duty factor of the driving current can be decreased, furthermore ensuring the stability to the induced noise due to the disturbance light and the like. |
