why long-life bulbs are dim
Boing Boing • • technology
Key Points:
- A lightbulb in a Livermore, California fire station has been burning for over 120 years, surpassing one million hours of use, but it emits very little light, drawing only four watts instead of the nominal 60 watts.
- Electronics blogger Maurycy explains that tungsten filaments would need to reach around 5,700°C to emit peak visible light, but since tungsten melts at 3,422°C, bulbs mostly emit infrared light, and hotter filaments produce more light but have shorter lifespans.
- The 1925 Phoebus cartel, a manufacturers' cartel, deliberately limited bulb life to 1,000 hours as part of price-fixing and anti-consumer practices to maximize profits.
- Maurycy suggests that competition on bulb lifespan led manufacturers to produce dimmer bulbs to extend life, and although the cartel lasted 14 years, modern incandescent bulbs typically last between 500 and 2,500 hours.
