| 摘要 |
<p>The switch mechanism and circuitry fit into a conventional type of switch-box housing. The switch which can be externally set manually, or can be activated internally by electro-magnetic, thermal or piezo-electric devices. The ambient light level is detected by a photocell which provides a signal screened for spurious spikes by a filter. A threshold adjuster and an automatic setting module generate signals which are processed in a central logic unit. The switch can be set to switch the light on or off at pre-determined light levels with controllable sensitivity. The lamp current can be cut abruptly or reduced gradually for example by a thyristor dimmer circuit. A timer can be set to switch the lamp on automatically or the switch automation can be manually overridden.</p> |
