| 摘要 |
PURPOSE:To make a normal oscillation in an invertor device by making no oscillation from, a zero cross point of an output voltage of a rectifier where the oscillation in a transistor invertor device becomes unstable, to a given delayed phase angle when lighting an electric discharge lamp using the transistor invertor device. CONSTITUTION:When the voltage from an AC power source 1 is made full-wave rectification in a rectifier 2, a semiconductor switch 23 becomes an OFF state at a zero cross point of output voltage, when an output voltage rises, the electric potential of a condenser 22 rises by a time constant determined with a resistance 21 and the condenser 22. Consequently, the switch 23 becomes an ON state and a transistor 5 is turned ON and a transistor 6 turned OFF, and a high frequency AC flows to an electric discharge lamp 14 connected to a secondary coil NS of an oscillation transformer 4 connected to the switch 23. Thus oscillation is made not to occur at a zero cross point of the device 2 with the switch 23 made to the ON or OFF state according to the variation of the electric potential of the condenser 22. |
