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Skeeter Skeeter is offline
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Default Do switch mode power supplies flicker in time with mains?

In article , root@
127.0.0.1 says...

On Thu, 20 Dec 2018 17:08:00 -0000, LO AND BEHOLD; "William Gothberg"
"William determined that the following was
of great importance and subsequently decided to freely share it with us
in :

On Thu, 20 Dec 2018 17:04:50 -0000, ?'s Owner 𾐶?
wrote:

On Thu, 20 Dec 2018 08:34:35 -0800 (PST), LO AND BEHOLD; trader_4
determined that the following was of great
importance and subsequently decided to freely share it with us in
:
On Thursday, December 20, 2018 at
7:51:32 AM UTC-5, William Gothberg
wrote:
On Thu, 20 Dec 2018 04:31:31 -0000,
Clare Snyder
wrote:

On Wed, 19 Dec 2018 13:03:19 -0500,
"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?
Since this landed in

alt.home.repair, I gotta ask. Do you
have single-phase or two-phase?
No
such thing as "2 phase" -
Perhaps he meant split phase, like in
the USA - centre tapped 240V.
Which could conceivably mean I could
have some lights on each circuit,
and if they were fed by half wave
rectification, flickering at 50Hz,
they could be out of time with each
other and make the whole room
flicker at 100Hz, filling in each
other's gaps. Mind you the same can
happen by just putting the bulb in the
other way (in the UK bayonet cap
fittings allow you to connect
live/neutral the other way at random with

bulbs).
They won't be out of time with each
other as each circuit is reaching
it's peak value at exactly the same time. That's how you get 240V,
120+120 = 240. they know a lot about
this over in alt.checkmate

What the **** are all those stars for?

to protest against white supremacy and fascism.


yay