Re: The lightbulb conspiracy
Just dug out another of the old books I rescued from the skip at GEC [ Incandescent Electric Lamps and their properties, Daniel H Ogley, Longman, 1914], which seems to provide the answer to the low voltage, low wattage bulb issue. Chapter VI discusses lamp construction, Chapter VII lamp properties.
In 1910, tungsten filament would have been produced by the "pressed filament" process, which was incapable of producing really fine filaments. By 1914, technology had moved on, and filaments could be produced by drawing tungsten that had been made ductile by heating and hammering while hot prior to drawing. So by 1914, it was possible to make wire less than 0.012mm diameter, allowing the manufacture of 10CP lamps for operation in excess of 200V. (Ch VI, page 50).
Chapter VII discusses life tests and reliability, and indicates that a 1000 hr life had been adopted for metal filament lamps, determined by filament failure rather than light output reduction due to blackening. Page 58 mentions the need to maximise the ratio between light output versus the costs of the lamp and electricity.
Further confirmation, if any were needed, that the alleged conspiracy simply reflects the usual situation in engineering where the optimum solution is one where nothing is perfect, but is a balance between conflicting parameters.
PDFs of Chapter VI and part of Chapter VII attached.
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