| 摘要 |
A controller 1 comprising a processor 5 and a switching unit 7 operable in response to the processor 5, the switching unit 7 comprising a triac device 11 and a latching relay device 13 arranged in parallel electrically with respect to each other. The controller 1 further comprises a low-cost yet flexible power supply 9 having an energy storage device such as a capacitor 59 to ensure successful latching of the relay in the event of power interruption to the controller 1. The circuit is designed to provide a controller that is cost effective to operate and will also be flexible in its application. The controller has particular application as a photoelectric control unit for lighting applications such as street lamps. The processor 5 has means to compare an ambient light value measured by a photoelectric sensor 3 with a predetermined threshold value. When the ambient light falls below the threshold value the controller operates to turn the lamp light on. |
