| 摘要 |
PURPOSE:To enhance the reliability of an illumination instrument for an emergency by keeping a display element in a lighted state for a long time, by lighting the display element by oscillation output by raising voltage of a storage battery by an inverter at the time of discharge. CONSTITUTION:When a commercial AC power source AC is cut off and the charging to a storage battery B is stopped, the supply of a current from the storage battery B is stopped, the supply of a current from the storage battery B to an inverter IN is started to perform emergent lighting. The voltage of the battery is gradually dropped by emergent lighting and a light emitting diode LED is put out. When the voltage of the battery falls below detection voltage V2, transistors Q1, Q3 are turned OFF while a transistor Q2 is turned ON and light emitting LED is lighted. When the voltage is further lowered, a fluorescent lamp L is put out and the inverter IN reaches a non-load state. Therefore, because LED can be lighted over a relatively long time by the voltage of the inverter after the fluorescent lamp L was put out, the reliability of an illumination instrument for an emergency can be enhanced. |
