Because of this, the lifetime of a filament lamp is a trade-off between efficiency and longevity.

Fluorescent lamps have much higher efficiency than filament lamps.

Some have lower efficiency than filament lamps, and some significantly higher.

The results on income when the consumption, as in the new metallic- filament lamps, drops to 1.25 watts per candle can readily be imagined.

The light source was a round concentrated filament lamp.

The Kremlin stars are illuminated from the inside by filament lamps so that they could be seen against the sky.

Note that a filament lamp is practically useless as a light source for optical communication.

The working part of a filament lamp is a metal coil which glows white hot.

In the past, ruggedized and under-run filament lamps were used to maximize the bulb life.

The largest electric incandescent filament lamp in the world, 50 kilowatts, was on display.