Time Constants of Incandescent Lamps

摘要

Candescence and nigrescence curves are shown for a number of tungsten lamps, vacuum and gas‐filled, ranging in size from the automobile lamps up to the 30‐volt, 30‐ampere lamp and the 1000‐watt photoflood lamp. Data are given for similar filaments mounted in vacuum lamps and in lamps filled with argon, nitrogen, hydrogen, and helium. The filament of a vacuum lamp reaches 90 percent brightness on heating in time t=0.060I0.54; 10 percent brightness on cooling in time t=0.022I0.70; for gas‐filled lamps, t=0.15I0.70 and t=0.070I0.70, respectively. (I is the normal operating current of the lamp.) The percent of total variation, P, in brightness during a cycle for a vacuum lamp on 60‐cycle a.c. is P=34D-1.06, on 25‐cycle a.c., P=28D-1.37; for a gas‐filled lamp, P=75D-0.89 and P=63D-0.91, respectively. (D is the filament diameter in mils.)