On Sat, 14 Jul 2018 13:13:42 -0700, you wrote:
I have both LED and CF lamps here. I can see some strobing
from the CF but none from the LEDs. Perhaps they use a high
frequency. There are different types, for instance some cars have
LED brake and rear lamps. I can see strobing on some and not on
others.
Fluorescent lamps strobe. When I was a kid they gave me a
headache. I could see the strobing all the time. I was also aware
of the flicker on British TV. The worst was lamps at Niagra Falls
in Canada where the house current was 25Hz.
Since fluorescents fire on every half cycle, the Niagra ones would
have had a 50 Hz flicker. Many people can see that. British and
other countries have a 100 Hz flicker, supposedly not visible. US and
similar countries have a 120 Hz flicker, even harder to see.
British TV had, IIRC, a 50 Hz frame rate, and I suspect a 100 Hz field
rate, so you still had a flicker that could be seen out of the corner
of your eye (the most sensitive part for movement, all rods...).
I remember seeing that when I saw British TV in England. Resolution
was lovely, but out of the corner of my eye, it flickered a bit.
Harvey
On 7/14/2018 1:04 PM, Geoffrey Thomas wrote:
I've bought some cheap led lamps (1w) for use as night lights on
the landings, they actually provide useful normal levels but they
do "strobe". This is only apparent when you move your hand close
to them. I see blue and yellow flashes out of the corner of my
eye when i blink under certain types of fluorescent lighting.
Geoff.
