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Old 28th Apr 2019, 8:15 pm   #54
broadgage
Nonode
 
Join Date: Jan 2010
Location: North Somerset, UK.
Posts: 2,129
Default Re: The lightbulb conspiracy

As others have posted, it is easy to make a longer lasting lamp, but at the expense of reduced efficiency and greater fuel bills.

1000 hours, was and still is, a sensible compromise for general use.

In years gone by, GLS lamps were available in a vast choice of voltages, not just to cater for differing supply voltages, but also to allow the better informed user to deliberately over run or under run when some special circumstances justified this.

I can remember theatre footlights that used 240 volt lamps for the white, amber, and red lights, but 200 volt lamps in the blue lights.
The blue lights tended to be rather dim, and over-running 200 volt lamps on a 240 volt circuit not only improved the light output, but also improved the percentage of blue.

GLS lamps of lower voltages tend to be more efficient, if life and quality of manufacture remain constant.
A 120 volt 60 watt lamp will be brighter than a 240 volt 60 watt lamp, other factors remaining unaltered.

50 volt 300 watt lamps used to be popular for street and industrial lighting and gave a better light than 240 volt lamps.

Mains voltage lamps of very low power are very inefficient and the thin filaments make them vulnerable to vibration.
A 6 volt 0.3 amp pilot light bulb worked from a transformer will give more light than an 8 watt nightlight bulb and last longer.
A 12 volt 21 watt vehicle bulb worked from a transformer will give a lot more light than a 25 watt mains bulb.
Before halogen lamps became popular, desk lamps and task lights that used a 21 watt car bulb were popular. Not only brighter, but a small and mass produced car bulb was cheaper to replace.
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