| 摘要 |
PURPOSE:To simplify a circuit constitution by a constitution wherein a pair of transistors controlling currents flowing to a capacitor are connected inversely parallel to each other, and a diode is connected in the forward direction to each transistor. CONSTITUTION:When a capacitor C1 has the polarity shown in the figure, a current flowing to the capacitor C1 via a resistor R1 is divided through the intermediary of a diode D1 and a transistor TR1, and when the capacitor C1 has the polarity inverse to that shown in the figure, it is divided through the intermediary of a diode D2 and a transistor TR2. Then, according to electric signals from DC currents E4 and E5 for control, the currents flowing through the transistors TR1 and TR2 are changed to regulate a current for charging the capacitor C1, and thereby an output of an incandescent lamp L is made variable. The diodes D1 and D2 act for preventing the discharge of the charge of the capacitor C1. |
