On 28/04/2021 05:39, Paul wrote:

https://spectrum.ieee.org/tech-histo...ulb-conspiracy

Yes, I think originally incandescent lamps (tungsten I assume) had a
lifespan of about 2500 hours, but (in 1925) they reduced it to 1000.

In the 1970s they started selling "double life" lamps that lasted 2000
hours (at a slight reduction in efficiency as they operated at a lower
temperature), but they never caught on as the standard ones were heavily
discounted, presumably due to volume production.

--
Max Demian