| 摘要 |
PURPOSE:To enhance the reliability by providing a switch element between the base and the emitter of a transistor, and turning it ON before the polarity of a current transformer is inverted, thereby facilitating the setting of a switching frequency. CONSTITUTION:Transistors (Tr)1, 2 are connected in series between the output terminals of a DC power source 3, the DC power is converted into an AC, and supplied to a load 7 (fluorescent lamp) of a resonator 4. The primary winding 9 of a current transformer 8 is inserted into the resonator 4, and a base current is supplied from the secondary windings 10, 11 to the Trs 1, 2. In this case, switch elements 12, 13 are provided between the bases and the emitters of the Trs 1, 2, and turned ON before the output polarity is inverted during the period for supplying the base current by the windings 10, 11 together with times 14, 15. Thus, when the voltage of the capacitor 17 of the timers 14, 15 arrives at the prescribed voltage, the elements 12, 13 are turned ON to turn OFF the Trs 1, 2. |
