On Wed, 05 May 2021 09:14:18 +0100, The Natural Philosopher wrote:

On 04/05/2021 22:00, Max Demian wrote:
On 04/05/2021 17:38, Fredxx wrote:
On 04/05/2021 13:23, Brian Gaff (Sofa) wrote:

OK what do they use then, 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. However it is obvious that even the briefest of
ons and
the longest offs tends to still be visible in most cases, and not
terribly
accurate if many leds are used as the load, there being a spread of
linearity in any given number.

PWM is the cheapest way as it needs no other component.

Yes, I made a PWM dimmer circuit (for fun) based on circuits I found on
the Internet and it works well, and dims to nothingness. (12VDC working
a white LED strip.)

do it at high enough frequency and there is no visible flicker, and you
can feed the LEDS via a small ferrite inductor with a parallel capacitor
and reduce HF flicker too.

Please tell the car manufacturers how to do this so I don't have to watch flickering tail lights while driving behind someone, or flashing headlights on TV.

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