| 摘要 |
<p>PROBLEM TO BE SOLVED: To prolong the life of an incandescent lamp in a simple way. SOLUTION: Filaments f1, f2 of an incandescent lamp are attached in parallel between electrodes. Moreover, a resistance R is connected in series to the filament f, and a timer T having a contact, which short-circuits the both ends of the above resistance with delaying time after power-source on, is formed. Or a semiconductor circuit equipped with the timer means and the duty ratio switching means is constituted, and it is made so that big current may not flow on the filament of the incandescent lamp after power-source on by phase control.</p> |
