| 摘要 |
PROBLEM TO BE SOLVED: To eliminate a darkness and ensure safe action by building in an emergency light using a storage battery containing a photosensor which acts only in dark ever in any service interrupt as a light source. SOLUTION: Current of power source input is regulated with a Mylar (R) capacitor C1 and a resistor R3, and full-wave rectified with diodes D2-D5, then smoothed with an electrolytic capacitor C2, and used to trickle change a nickel- cadmium battery BT. When a AC power source is shut off in emergency, power source voltage is lowered, the base potential of a transistor Tr1 is lowered, the transistor Tr1 is turned on, voltage of the battery BT is supplied via the transistor Tr1, and when a room is well-lit, the resistance value of a photo sensor cds is decreased, transistors Tr3, Tr2 are turned off, current does not flow, and a luminaire will not light. Conversely, when a room is dark, the resistance value of the photosensor cds is increased, the transistor Tr3 is truned on, the base potential of the transistor Tr2 is raised, a collector and an emitter are electrically connected, and an electric lamp is lit. Thereby, when the room is well-lit, lighting can be avoided.
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