| 摘要 |
PURPOSE:To enable a discharge lamp to light again when it is attached again after removal by resetting the timing activity of the first timer circuit to its initial state by provision of a lamp state detection circuit. CONSTITUTION:A starting circuit 4 is started in its operation by action of the first timer circuit and stopped after a set time. A lamp state detection circuit 5 is incorporated in an inverter circuit 1, and this detection circuit 5 consists of resistors R21 and R32, a diode D21, and a transistor Q31. The placement state of a lamp l is detected by measuring the voltage between the terminals of a resistance R32. When the lamp l is removed, the voltage between both terminals of the resistance R32 becomes nearly zero, and a base current flows in a transistor Q31 owing to the voltage between both terminals of a capacitor C22 working as a timer in the starting circuit 4, thereby turning the transistor Q22 on, along with discharge of the capacitor C22, to reset the first timer circuit. |
