The bulb that was made to burn out sooner
The “secret” was not a hidden flaw in glass or wiring. It was a lifespan target. In the 1920s, major lamp makers organized the Phoebus cartel and standardized many incandescent bulbs around a 1,000-hour life. Longer-lasting bulbs were possible; the agreement made durability something manufacturers were expected to limit.
Why a brighter bulb has a shorter life
An incandescent bulb makes light by heating a thin tungsten wire, called a filament, until it glows. Run that filament hotter and the bulb produces more light from the same amount of electricity—but tungsten evaporates faster, thinning the wire until it breaks. Run it cooler and it can last longer, though it gives off less light for the power it uses.
That engineering tradeoff gave manufacturers room to choose a lifespan. The cartel’s standard turned that choice into a coordinated business policy. Members tested bulbs and could penalize makers whose products lasted too long, helping prevent one company from gaining an advantage by selling unusually durable lamps.
From engineering choice to business model
The episode is an early, unusually clear case of planned obsolescence: designing or regulating a product so that customers must replace it sooner than they otherwise would. It did not mean every bulb was deliberately sabotaged, nor did it invent the practice. Its significance was that companies treated a product’s useful life as something they could manage collectively—not merely a result of how well it was built.
A burned-out bulb could look like an unavoidable accident. Under the cartel’s standard, its short life was also part of the product’s design.
