摘要 |
The cigarette lighter has an electrical resistance that glows red hot when a voltage is applied and forms part of an incandescent dervice (12). This device is formed at the bottom (14) of a tubular holder (11) open at one end (15). The device can move axially towards and away from the said bottom and in this way operates the switch that applies a voltage to the resistance. A bimetal piece fixes the time for which a voltage is applied to the resistance and is heated by the incandescent device. The degree of opening (15) is limited by a ring (17) made of transparent plastics material. The ring moves axially from its outer position on the bottom (13) and closes the supply switch. The incandescent device may be a metal coil. ADVANTAGE - Simple to make and use. Cheap. No esp. care need to avoid fire. |