On 28/04/2021 00:14, Dave Plowman (News) wrote:

Think it's generally known that dimming a tungsten bulb reduced its
efficiency dramatically. In other words, a 100w dimmed to half brightness
used a lot more electricity than a 50w on full. Although dimming did
extend the life of the bulb.

So how about LEDs? Since they generate far less heat are they still as
efficient when dimmed? And does dimming make a difference to their life?

Increase it a bit I would have thought. Of course you've got to dim it
using PWM (from DC) or trailing edge (AC).

(I've seen idiot YouTube videos describing circuits that control LEDs
with potentiometers, either directly or via a power transistor; it's
inefficient and liable to overheat the pot and/or the transistor as some
of the comments say; also I think that controlling white LEDs in this
way is liable to change the colour of the light.)

Idiot YouTubes:
https://www.youtube.com/watch?v=wns8xrxTYhU
https://www.youtube.com/watch?v=OnjNXhxxc9w

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Max Demian