| 摘要 |
PURPOSE:To enhance the reliability in a simple circuit configuration by controlling ON, OFF a switching transistor by the output by a phototransistor, and varying the output voltage. CONSTITUTION:Many parallel circuits of transistors 11 and voltage dividing resistors 10 are connected in series, its intermediate point is used as an anode terminal, and the anode voltage is varied by controlling a light signal to a phototransistor 13. When the voltage of the capacitor 3 is, for example, set to 100kV and the number of series transistors 11 are 100 pieces, the intermediate point is decided at the point of 50 piece of the series. When the all transistors 11 are OFF, the voltage V1 becomes 50kV, and when the all transistors 11 from the intermediate point between the cathodes are turned ON, the voltage V1 becomes 0kV. Accordingly, the voltage V1 varies by approx. 1kV by controlling ON, OFF only one transistor 11. |
