| 摘要 |
A method and apparatus for normally illuminating a monitored area with light applied at a relatively low intensity, and increasing the illumination automatically when intrusion into the monitored area occurs. A flood lamp normally operates at reduced power to illuminate the area, and a lens focuses the light on a photocell. Intrusion into the monitored area creates a change in the amount of light received by the photocell and produces a signal which is amplified and used to initiate a two minute timer. The two minute timer output initiates a 1.5 minute timer which causes the lamp to operate at full power during its 1.5 minute timing cycle. The lamp then reverts to its low power operating mode, and the additional one half minute timing cycle of the two minute timer provides adequate time for dissipation of transient responses which occur when the lamp is dimmed. A regulator circuit prevents unwanted variations in illumination as a result of spurious variations in the power to the floodlamp.
|
