| 摘要 |
A lighting system, which includes one or more lighting apparatus sets, includes a control circuit. The control circuit has an ambient light sensing component and processing circuitry which produce a control signal whenever the intensity of ambient light reaches a given level and remains at that level or less. A delay (debounce) circuit receives the control signal and provides an output upon the expiration of a predetermined time interval which effects the transfer of power to the lighting apparatus set or sets and starts a timing circuit which is operatively arranged to assure continuing transfer of power to the set or sets for a given time interval, at the expiration of which power is removed from the set or sets. An alarm circuit also controlled by an output from the timing circuit may provide a warning alarm shortly before the expiration of the ON time interval. The control circuit may also turn OFF the power to the set or sets when ambient light of a set intensity becomes present.
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