On Fri, 04 Oct 2019 16:28:06 +0100, whisky-dave wrote:

On Friday, 4 October 2019 15:32:22 UTC+1, Commander Kinsey wrote:
On Fri, 04 Oct 2019 09:41:25 +0100, PeterC wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters have
covered, LED lamps have some current regulation or power supply built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is 0.86 and
is luke warm. The real warmth in the 2nd. one is around the inputs though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor of 1.00, at 256V, 9.8W.


I doubt that it's just the LED, you shouldn't include the PSU in such calculations especailly if running off mains AC, because you're including the LED+PSU so not really gettign any info about the actual LED.

Why should I not include the whole unit? Surely that's all that matters.