"William Gothberg" "William wrote in message
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On Sat, 22 Dec 2018 21:27:05 -0000, Rod Speed
wrote:
"William Gothberg" "William wrote in message
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On Sat, 22 Dec 2018 02:53:46 -0000, Rod Speed
wrote:
"William Gothberg" "William wrote in message
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On Fri, 21 Dec 2018 23:09:51 -0000, Rod Speed
wrote:
"William Gothberg" "William wrote in
message
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On Thu, 20 Dec 2018 18:55:13 -0000, Rod Speed
wrote:
"William Gothberg" "William wrote in
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On Thu, 20 Dec 2018 08:19:58 -0000, gregz
wrote:
Clare Snyder wrote:
On Wed, 19 Dec 2018 19:34:57 -0000, "William Gothberg" "William
wrote:
On Wed, 19 Dec 2018 18:03:19 -0000, Clark W. Griswold
wrote:
On 12/19/2018 11:36 AM, William Gothberg wrote:
On Wed, 19 Dec 2018 16:18:29 -0000, Mark Lloyd
wrote:
On 12/19/18 5:23 AM, William Gothberg wrote:
Do switch mode power supplies flicker in time with mains?
Specifically
LED power supplies in commercially available domestic
lamps.
By
in
time, I don't mean at the same 50/60Hz, but anchored to it.
I.e.
if
you
have several such lamps each with their own built in
supply,
will
they
all flicker in time, using the mains frequency to keep them
in
time, or
will they be random, making the room overall not flicker
due
to
them all
being random? And is there any way I can test this? I
tried
taking
photos of them, but my camera only goes as fast as 1/2000th
of
a
second,
which shows all the lights at the same brightness each
time,
I
suspect
the flicker is above 2000Hz.
I once had an audio amplifier with a solar cell rather than
a
microphone
for the input transducer. This made it possible to listen to
light.
The
sun is steady, incandescent lights (AC powered) hum.
That was 40 years ago. Maybe something like that would work
today.
The trouble is I want to compare 2kHz+ from one light with
2kHz+
from
a neighbouring light and see if they're in sync.
Maybe use a dual trace oscilloscope?
Haven't got one unfortunately.
Since this landed in alt.home.repair, I gotta ask. Do you
have
single-phase or two-phase?
Single. I'm in the UK.
so 50 Htz - you can almost see an incandescent flicker at that
frequency (at 25 you could)
(also rules out the previously mentioned "engineer friend")
Lights flicker at twice the frequency, once for positive cycle,
and
once
for negative cycle. LEDs only once unles using a bridge
rectifier,
or
steady on using DC. Even though blinking they look normal
straight
on,
my
brain says something is wrong
Some brains (or eyes) seem to be faster than others. I can easily
(and
annoyingly) see flicker on CRT monitors below 90Hz, others don't
even
see
the 50 or 60Hz ones. I can see flicker on 80% of car LED lights,
others
don't see any. Designers really ought to account for those of us
with
better eyesight.
No point in doing that.
There is when half the population is capable of seeing it.
Half the population isnt.
Then you must know a lot of people with ****ed eyesight.
Nothing ****ed about not seeing flicker on car lights.
Your eyes are clearly operating more slowly,
Nope, just a lower flicker fusion threshold
at a lower frame rate.
Eyes don't have a frame rate.
The eyes and the brain together have a frame rate.
No they do not. They actually have a flicker fusion threshold.
https://en.wikipedia.org/wiki/Flicker_fusion_threshold
Easily measured.
Even the flicker fusion threshold isnt. It varys with the
part of the eye the light that is flickering is viewed by
and by the intensity and depth of flicker too.
https://en.wikipedia.org/wiki/Flicker_fusion_threshold
Why only sell things suitable for those with ****ty eyesight?
They are actually designed to work fine for all but freaks.
Why would you call someone with better eyes a freak?
Worse eyes when you see flicker with car lights.
No, I see what's really there.
No you don't. Most obviously with higher flicker rates that you don't see
either.
I see more than you do.
And that's obviously a bad thing when you
see flicker with car lights that only freaks see.
Why buy a 25fps video camera when you can buy a 50fps video camera?
Nothing whatever to do with video cameras.
If you can't see the flicker that I can, then your eyes aren't as
good as mine.
Nothing good about eyes that see flicker everywhere.
We see what is really there, you don't.
Still ****ed to have all car lights flicker. You're a freak.
But they are flickering.
But its better not to see that. You're a freak.
It is better to see what is really there.
Like hell it is with car lights, movies, TVs, fluoros, monitors etc.
What other things are you missing in life?
None with the flicker fusion threshold.
In fact I don't get to be ****ed off about flicker in common
stuff like car lights, TVs,. movies, fluoros etc etc etc.
Go film one with a video camera, or just look up a video of one.
I know they flicker, that's irrelevant to
whether it makes any sense to see that.
I don't see any flicker with movies and it makes no sense
to be able to be see the flicker that is certainly there.
You don't see it because CRTs had phosphors to match the frame rate,
Wrong, as always with movies in movie theaters.
they would stay lit for the 50th of a second between each illumination.
Same is done now with LCDs.
Wrong, as always. There is no persistence with lcds.
Only cheap rubbish TVs and monitors don't match the phosphor timing with
the scan timing.
Pity about movies in movie theaters, car lights etc etc etc.