"William Gothberg" "William wrote in message
news
On Fri, 21 Dec 2018 23:09:51 -0000, Rod Speed
wrote:



"William Gothberg" "William wrote in message
news
On Thu, 20 Dec 2018 18:55:13 -0000, Rod Speed
wrote:



"William Gothberg" "William wrote in message
news 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.

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.

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.