| 摘要 |
PURPOSE:To attempt the improvement of durability, reliability, stability and facilitation, relative to the lighting circuits in the title, by controlling a switching element in accordance with voltage in a feedback winding through a control circuit, and then keeping the output of a self-excited type inverter circuit constant and at the same time making a light adjustment through a light adjuster circuit. CONSTITUTION:When voltage in a feedback winding 11 ries with the large output of a self-excited type inverter circuit 3, a control circuit 21 controls a transistor 5 to lower the output of the self-excited type inverter circuit 3. When voltage in the feedback winding 11 also falls with the small output of the self-excited type inverter circuit 3, the control circuit 21 controls the transistor 5 to heighten the output of the self-excited inverter circuit 3. When a light adjuster circuit 20 is opened, then the self-excited inverter circuit 3 gives the entire light output thereof for putting the entire light to an electric discharge lamp 16. When the light adjuster circuit 20 is closed, part of the base current flowing through the transistor 5 is bypassed to lower the output of the transistor 5, with lowering the output of the self-excited type inverter circuit 3 to put a dimmed light to the electric discharge lamp 16. This makes it possible to attempt the improvement of durability, reliability, stability and facilitation, relative to the lighting circuits in the title. |
