On 08/03/2015 21:12, john james wrote:

You not being able to explain how you work out what the
backlight intensity of a particular TV from the house power
consumption when there are two TVs on different programs noted.

If you have an LCD set without dynamic contrast enabled the power
doesn't vary anyway (well not enough to be able to tell what program is
on). If you have a plasma set you can probably tell but who has them
these days?