31 Oct
2011
31 Oct
'11
9:29 a.m.
On 31 Oct 2011 at 9:47, David Riley wrote:
It's very distracting and irritating, and I doubt
the lower frequency
saved them more than a few cents per $30,000 car in drive electronics.
We're approaching the time of year when my field of vision is
polluted with those damned flickering LED outdoor Christmas tree
light displays. I must have some sort of visual impairment because I
can pick out the flicker from a mile away--literally. It reminds me
of a nest of ants crawling all over the display.
It seems that the usual method of implmentation (in the US, anyway)
is to use a string of LEDs to self-rectify the AC line current,
resulting in a pronouced 60Hz flicker. I picked up a couple of
strings of said lights last year (GE brand) and hooked them to a
fullwave bridge rectifier, with a single large (220 ?F filter cap).
The flickering ceased, but the quailty of light is rather harsh,
particularly when compared side-by-side with an incandescent string.
l suspect it won't be long before consumer and legislative pressures
means that our Christmas seasons will be uniformly polluted by hordes
of ants dancing over our lighting displays.
Moral: Even a 60Hz multiplex rate is too slow for some people's
vision.
--Chuck