Post by @xenotar
The thing that makes modern dimmers for lighting complicated is basically what Einstein got his Nobel prize for.
Very crudely:
Our eyes are "peak-detectors", and since LED's emit monochromatic light, you modulating the LED in time does not dim the light very much in our perception.
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This was first noticed during the development of the HP-35 calculator, search for "current" in:
https://www.hpmemoryproject.org/wb_pages/j_minck_01.htm
("White LED" are blue LED with a "phosphor" layer to down-convert to other colors.)
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@bsdphk@fosstodon.org @fivetonsflax@tilde.zone @dpiponi@mathstodon.xyz Thanks for the link; I’ve always been curious about the history of HP calculators, the algorithms, and the people who created them. I had early access to an HP-45 as a teenager, and later to an HP-25, where I learned to program with the help of the manual. I have fond memories of HP calculators.