| 摘要 |
PURPOSE: To provide a power supply circuit adequate to be used for a gas discharge lamp more than one unit for placing a document under light exposure by placing a control means in connection between the secondary main winding and a gas electric discharge lamp. CONSTITUTION: The secondary main winding 8 is placed in further connection via a controllable switching means 13, for example, each relay connected to each terminal of a gas electric discharging lamp. Together with the mutually adequately connected primary windings 5, 6 of a transformer 7, transistors 2, 3 form a push-pull transformer. Transistor 2, 3 functioning as a switching transistor are driven by a control circuit 4. A control signal 28 regulates a standby mode, a circuit 27 is opened via a contact piece 13, accordingly via a signal 26 and the control circuit 4 is kept in its standby mode, and transistors 2, 3 are mutually connected at comparatively small duty cycle. The duty cycle is regulated so that voltages supplied to respective filaments 17, 18 of a gas electric discharge lamp 16 by means of the secondary auxiliary windings 9, 10 of the transformer 7 may become desired values. |
