dilbert said:
Not only that but eyes ... "retain" (?) the light they see for a relatively long period of time too.
At 50Hz, the cycle time for the lights (and all of the old CRT TVs) in most houses is 20ms yet nobody ever worried about that.
Is that your opinion? :
Incandescent lights don't flicker perceptibly, because the filament doesn't cool significantly as the power cycles. Fluorescent lights with magnetic ballasts do flicker, but they do so at
twice the frequency of the current alternation...so that's 10 ms for 50 Hz power. Of course no one complains about that, since the typical flicker fusion threshold is ~13 ms. Modern lighting – fluorescent with electronic ballasts, LED – also usually flicker, although electronic-ballast fluorescent lighting flickers in the µs range (kHz range), and LEDs flicker at 100 or 120 Hz (although some bulbs convert power to DC so effectively don't flicker at all). Bottom line, lighting in most houses does flicker, but too fast for normal, direct perception. If their lights flickered at 20 ms as you suggest, people certainly would complain. Well, except in dilbertland, because the laws of physics don't apply there, apparently.