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by housemusicfan 1043 days ago
> which adjusts the input voltage to the bulb

This isn't exactly true; no one has used a rheostat for dimming in like 50 years since that just wastes power. Most incandescent dimmers implement cycle chopping where they clip the beginning or end of the AC cycle (the type used depends on the implementation). Most commonly done using a diac or triac. Most "LED" in wall dimmers work this way too because you can't PWM dim on the other side of the power supply. This is also why in practice most LED bulbs are shit and even the best bulbs will visibly flicker whilst dimming. Yes LEDs are DC but as a compromise you have to implement dimming on the AC side because homes are wired with AC power.
1 comments
midoridensha 1043 days ago
>Yes LEDs are DC but as a compromise you have to implement dimming on the AC side because homes are wired with AC power.

This isn't universally true. Here in Japan, there's commonly-available LED ceiling fixtures (that look something like UFOs) that are dimmable with a remote control. They surely use PWM dimming, but it's done in the LED driver circuit; the fixture is getting the same 100VAC at all times. They also commonly have bluer and yellower LEDs, so you can adjust the light spectrum with your remote control.

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housemusicfan 1043 days ago
Yes but we are talking about bulbs (with Edison base) here not all-in-one fixtures. Yes, the same could be said about ceiling fans with built in remote receiver. The problem with these of course is you need the remote, and if you lose it you're out of luck. Some manufacturers make a little dock for the remote that would go in place of the light switch but I happen to think those are silly.
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midoridensha 1043 days ago
>Yes but we are talking about bulbs (with Edison base) here not all-in-one fixtures.

Sure, but there's little difference between the two practically. Both of them are a light-emitting device, which plugs into a simple, standard socket on the ceiling. The ones I refer to are bigger, since they're meant to light up a whole room, but otherwise not really different, except that the standard socket is a lot better and easier to use (you just turn the fixture a quarter-turn to plug it in).

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