On Thu, 20 Dec 2018 19:24:19 -0000, Rod Speed wrote:



"William Gothberg" "William wrote in message
news
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.

Not necessarily. Its quite possible to do a capacitor dropper powering
a current regulator that way. Have a look a Big Clive's teardowns.

I've looked inside and I now know they are SMPS.