| 摘要 |
PURPOSE:To obtain a high power factor at low harmonics by a method wherein a high-frequency current is supplied to a load circuit from the side of a power supply via a parallel circuit which is composed of a second diode and an eighth capacitor. CONSTITUTION:A resonant capacitor 5, a resonant circuit which is constituted of a parallel circuit for a resonant choke TO and a series circuit for a main transistor Q1 which is turned on and off at a high frequency are connected across both ends of a smoothing capacitor C2. In addition, the contact of a high-frequency choke TH with a first diode D1 is connected to a collector for the main transistor Q1 via a parallel circuit which is composed of a second diode D2 whose anode has been connected to the side of the contact and of an eighth capacitor C8 and via a series circuit which is composed of a discharge lamp FL and a ballast choke TB. Then, a high-frequency current is supplied to a load circuit from the side of a power supply AC via the parallel circuit which is composed of the second diode D2 and the eighth capacitor C8. Thereby, a high power factor can be obtained at low harmonics. |
