Time Constants of Incandescent Lamps

Abstract

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.)

A photon-recycling incandescent lighting device

“…S11A), which is much shorter than that of the conventional incandescent bulbs (ca. 0.15 s) ( 23 ). The corresponding heating and cooling rates of the JTE are ca.…”