On Thu, 20 Dec 2018 13:19:55 -0000, whisky-dave wrote:

On Thursday, 20 December 2018 13:00:02 UTC, William Gothberg wrote:
On Thu, 20 Dec 2018 09:36:02 -0000, Jon Fairbairn wrote:

"William Gothberg" "William writes:
Agreed. All I can detect (with my digital camera) is that
one brand of LED light I have flickers about 5 times less
(not sure if it's smother or faster) than the others.

Try a longer exposure and move the light rapidly relative to the
camera.

I wonder, if I fed the lamps with mains voltage DC, simply a bridge rectifier and a huge capacitor,

No they'd probbaly blow up, don;t forget a bridge recifir would produce a voltage of at leat 330V and the power dissapated by each LED would also increase .

I thought about that, and the cheapest one, which seems to be just a bridge rectifier straight to the LEDs, would make them 65% brighter. But the others should only get 4% brighter. A switched mode supply fed by DC at the peak voltage of the mains, would still have its bulk capacitor at about the same voltage. It's already doing what I'm suggesting I do externally. They're rated at 85-260V, so I assume they're switched mode.