| 摘要 |
PURPOSE:To prevent the brightness of a luminescent diode from fluctuating when the voltage of power flucturates, by adding a transistor to a circuit consisting of a constant voltage diode and two silicon controlled rectifiers controlled through a sensor circuit. CONSTITUTION:The transistor 24 is turned on or off by the action of the sensor circuit 1 such as a proximity switch to control the silicon controlled rectifiers 22, 23. A diode 32 is connected between the cathode of the constant voltage diode and the node of a resistor 26 with a capacitor 29. Current is kept by the diode 32 from flowing thorugh the resistor 26. Thereby, the leaking current during the turn-off of the silicon controlled rectifier 22 is reduced. A transistor 35 is coupled between the gate and cathode of the silicon controlled rectifier 23. Therefore, a low gate current is sufficient to trigger the silicon controlled rectifier 23. Even if the power voltage fluctuates, stable phase control is perforemd. Thereby, the fluctuation of the brightness of the luminescent diode 34 is prevented. |
