Shutting fuel off whie driving. Into fluorescent lights

[Matt S Bower]

Dave Williams wrote:
> 
> -> Actually fluorescent lights flicker on and off 120 times a second.
> -> Fluorescent lights flicker on the positive side AND negative side of
> 
>  Still doesn't matter.  It takes time for a flourescent to turn on or
> off; the 'flicker' is just a slight change in intensity, not actually
> going from bright to dark.
> 
Yes but if you use an optical tach the light does flicker enough to give
you a reading of 7200 RPM (ie 7200RPM / 60 Sec. = 120 Hz).  They are
also known to give a lot of people a headache from being under them to
long.  So whether the light goes all the way off or not it does still
flicker and 120 Hz is the edge of the perceptible to human vision range.