On Wed, 17 Sep 1997, Eric van Es wrote:
> Martin R. Green wrote:
>
> After all the lightsbulbs in SA all run off 220V 50Hz. Only sometimes
> you detect a flicker - usually when there's a power dip. I suppose it's
> because the filament does not dissipate its rated power and
> illuminescence....
>
PTM: If you put a diode in series with a pulp you got a very annoying
flicker in spite of the resulting 25 Hz. This same 25 Hz doesn't flicker
in TV or movies. I have myself started to speak about the dead time.
In case of the pulp and the diode the dead time is <50%, in movies about
5..10% (?) and in TV it depends of the phosphor.

Phosphors user in CGA and VGA are rather 'fast'. In Hercules and MDA they
used slow phosphors. Because of this fast phosphor you got to use high
scanning rates in VGA.

This dead time seems to be very good explanation. I have not tested yet,
but I have a very good testbench for this, so I might some of these days.
Our staff in psychology has made this kind of work for years and they have
_very_ interesting results about movies, TV and brains. One of the best is
(as I understood it) that our center of speaking in the brains have the
same resonance frequency as this flicker. It means that you will have
troubles when you try to speak while watching TV. This also explains why
it is so difficult to leave the TV when you have started to look.
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