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True Metal Filament Lamps

المؤلف:  GEORGE A. HOADLEY

المصدر:  ESSENTIALS OF PHYSICS

الجزء والصفحة:  P-425

2025-12-15

570

of high efficiency have also been developed. These lamps depend upon the possibility of drawing certain of the less common metals, like tantalum and tungsten, into a flexible wire of very small diameter- 0.1 mm. or less - and also upon the ability of these wires to carry a current that brings them to incandescence without bringing them to the melting point. The tungsten lamp (Fig. 1) is of much higher efficiency than the carbon or metallized filament lamp. A 40-watt tungsten lamp will give 32 candle power or more, requiring less than 1.25 watts per candle power. This is most important to the consumer, because what he pays for is watt hours and what he wishes to use is light, hence a tungsten gives him twice the returns that a metallized filament lamp gives.

Fig. 1