long-life technique in light bulbs - between 20,000 and 100,000 operational hours using ""ordinary"" light bulbs

11-28 — elektor november 1980 Between 20,000 and 100,000 operational hours using "ordinary" light bulbs. When the famous Berlin clock was put into operation its inventor Dieter Binninger was faced with a problem. The time indication used an array of ordinary bulbs. Unfortunately, they only lasted a matter of weeks due to the constant switching on and off and the vibrations caused by passing traffic. Since the clock is so high up that scaffolding is needed to change the bulbs, this became an extremely expensive business. Using special light bulbs, so-called SIG lights, didn"t help matters, as their failure rate was still too high in spite of their special construc- tion. long-life technique in light bulbs Experimenting with light bulbs The lifespan of a light bulb at normal voltage levels in vibration-free surroun- dings is about 1000 hours. This period is determined by the speed at which the filament material condenses, which in turn depends on the temperature of the filament. D...