双灯丝调光白炽灯泡由玻壳、灯芯、常亮灯丝、备用灯丝、开关等组成。在玻壳内设置一备用灯丝,备用灯丝串接开关并联在常亮灯丝两端,开关固定在灯头内,灯头上有开关孔。正常使用常亮灯丝发光;当常亮灯丝断裂时,将灯头内开关闭合,备用灯丝发光,灯泡仍能继续使用;在正常情况下,闭合开 Double filament dimming incandescent bulbs by the glass, wick, often filament, spare filament, switch and other components. A spare filament is arranged in the glass bulb, the spare filament is connected in series with the switch in parallel at both ends of the filament, the switch is fixed in the lamp cap, and the lamp cap has a switch hole. Normal use of the filament often light; when the filament is broken, the lamp will be closed within the switch, the standby filament glow, the light bulb can continue to use; under normal circumstances, closed open