| 摘要 |
<p>The condition of a lamp (12) activates a permanent memory two-state display (14) which displays the condition during the daylight when no power is connected to the lamp. An electrical circuit (10) powered by electricity drawn from power lines is connected to the line such that the circuit is energized only when the lamp is supposed to be lit. The line current is measured when the lamp is supposed to be lit in order to determine the condition of the lamp, and provide an appropriate signal for controlling switches within the circuit.</p> |
