Brian Gaff (Sofa) wrote

OK what do they use then,

A controlled current regulator.

All I remember from my brief experience trying to dim leds was that the
most successful way of doing that was by duty cycle, ie on to off times
with them driven by some kind of oscillator with variable mark space
ratios.

It is much better to control the current thru the leds.

And it makes no sense to use a triac when varying
the mark/space ratio with leds anyway.

However it is obvious that even the briefest of ons and the longest offs
tends to still be visible in most cases,

That’s mad, leds have very little inertia.

and not terribly accurate if many leds are used as the load, there being a
spread of linearity in any given number.

That would be a mad approach too.

Rod Speed wrote
Brian Gaff (Sofa) wrote

Never saw the original post.

He ****ed up uk.d-I-y he had uk.diy

There is a holding current in a triac, and once the current drops below
this a kind of Hysteresis occurs so you need to turn it up to get it
conducting again.

leds don’t dim using triacs but still cant be dimmed right down close
to zero for use as a nightlight with the philips hues particularly.

Rod Speed wrote
Commander Kinsey wrote
Is it to warn you?

No idea what you are on about this time.
Even my toilet cistern can slow down smoothly.

Rather different technology. Many dimmers cant,
they cut off abruptly at the lower light levels.