Do switch mode power supplies flicker in time with mains?

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zuan1nu5o5piw3@desktop-ga2mpl8.lan...

On Wed, 19 Dec 2018 23:53:42 -0000, Rod Speed <rod.speed.aaa@gmail.com
wrote:



"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zt920ry6o5piw3@desktop-ga2mpl8.lan...
On Wed, 19 Dec 2018 16:21:41 -0000, Mark Lloyd <not@mail.invalid> wrote:

On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under
the
LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon
wheels
in movies.

It looks absolutely ridiculous with modern cars with LED headlights in
films. How hard can it be to put a smoothing capacitor on the output of
the power supply?

No point when the only thing that has a problem is videos.

It's fucking annoying watching them on TV.

Doesn't annoy me.

You don't even see a problem with dashcams.

There's a damn big problem with distracting drivers. Anyone with decent
sight can see it.

Clearly it doesn't annoy them enough to matter or they
arent as stupid as you and don't get annoyed by it.

 

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zuaweippo5piw3@desktop-ga2mpl8.lan...

On Thu, 20 Dec 2018 01:31:30 -0000, Rod Speed <rod.speed.aaa@gmail.com
wrote:



"Brian Gaff" <briang1@blueyonder.co.uk> wrote in message
newsvdu3r$oo6$1@dont-email.me...
Well the answer as in many things these days is it depends.
Some are very simple and do have a kind of pulsing taken from ripple on
the mains. Others seem to not do this, indeed poking a phototransistor
connected to an amplifier shows many different results. the same seems
to
go for CFLs as well.
You would need to know what circuit they were using etc to figure out
why.
One particular led in a stood across the road has a 1khz whine when
point
the device at it but modulated onto a 100 hz buzz.

I often wonder if there is some jiggery pokery going on to drive leds
hard
for split seconds to make them brighter.

Yes, there is, particularly with the brighter ones like car headlights
etc.

Those designers need to do more research and realise that a lot of the
population have eyesight good enough to detect that flicker

In fact fuck all of them do and they clearly don't themselves.

and should therefore increase the frequency of the flicker, or they're
causing distractions and a danger on the roads.

Clearly those that set the standards for cars know otherwise.

You're just a freak.

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zt9okmwvo5piw3@desktop-ga2mpl8.lan...
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.

 

[Daniel60]

Mark Lloyd wrote on 20/12/2018 3:21 AM:

On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude.  I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under
the LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.
... and, in real life, the Mag wheels of some cars seem to be spinning
backwards, dependant on the speed at which the car is travelling!!

--
Daniel

 

[Peeler]

On Thu, 20 Dec 2018 14:13:16 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

> It must be more complicated than that, most likely with the shutter time.

OTOH, baiting you senile idiots always comes EASY to him! LOL

--
MrTurnip@down.the.farm about senile Rot Speed:
"This is like having a conversation with someone with brain damage."
MID: <ps10v9$uo2$1@gioia.aioe.org>

 

[Peeler]

On Thu, 20 Dec 2018 14:14:58 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

It's fucking annoying watching them on TV.

Doesn't annoy me.

Let's just agree that BOTH of you idiotic sociopaths keep annoying normally
evolved humans!

 

[Peeler]

dOn Thu, 20 Dec 2018 12:13:07 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

Fucking annoying if you have decent eyesight, I can see the flicker from
almost everyone's LED tail lights.

Stiff shit for you. You're a freak and get to like that or lump it.

He's a TROLL, and he gets you to suck him off, EVERY time he feels like he
wants to be sucked off by you! LOL

--
The Natural Philosopher about senile Rot:
"Rod speed is not a Brexiteer. He is an Australian troll and arsehole."
Message-ID: <pu07vj$s5$2@dont-email.me>

 

[Peeler]

On Thu, 20 Dec 2018 12:31:30 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:


> Yes, there is, particularly with the brighter ones like car headlights etc.

Alas, the light in your senile head doesn't shine too bright, senile oaf!
<G>

 

[Peeler]

On Thu, 20 Dec 2018 12:52:31 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

<FLUSH another 183 lines of the two prize idiots' usual absolutely idiotic
drivel unread again>

--
Bod addressing abnormal senile quarreller Rot:
"Do you practice arguing with yourself in an empty room?"
MID: <g4ihlaFh5p5U2@mid.individual.net>

 

[Peeler]

On Thu, 20 Dec 2018 15:22:59 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

You're just a freak.

You said that already several times, but you STILL keep sucking him off,
miserable and lonely as you are, you senile freak!

--
Norman Wells addressing senile Rot:
"Ah, the voice of scum speaks."
MID: <g4t0jtFrknaU1@mid.individual.net>

 

[William Gothberg]

On Thu, 20 Dec 2018 09:36:02 -0000, Jon Fairbairn <jon.fairbairn@cl.cam.ac.uk> wrote:

"William Gothberg" <"William Gothberg"@internet.co.is> writes:
Agreed. All I can detect (with my digital camera) is that
one brand of LED light I have flickers about 5 times less
(not sure if it's smother or faster) than the others.

Try a longer exposure and move the light rapidly relative to the
camera.

Good idea.

I just tried it with the best lamps I have, which show a slight variation in brightness at exactly 100Hz, which must be seeping through from the mains. However the LEDs never go off, they just change brightness by 8%.

With the worst lamp, same 100Hz, but they actually go right on and off, with a duty cycle of 0.6.

Am I right in thinking these aren't SMPS at all?

 

[William Gothberg]

On Thu, 20 Dec 2018 11:57:01 -0000, whisky-dave <whisky.dave@gmail.com> wrote:

On Wednesday, 19 December 2018 16:35:05 UTC, William Gothberg wrote:
On Wed, 19 Dec 2018 16:21:41 -0000, Mark Lloyd <not@mail.invalid> wrote:

On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under the
LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.

It looks absolutely ridiculous with modern cars with LED headlights in films. How hard can it be to put a smoothing capacitor on the output of the power supply?

It's easy but that isn't the point. The most efficient way of driving to make maximium power into the LED means yuo have to pulse the LED's. Using a capcitor to smooth out the DC is yet another mode of inefficincy as it would get warm due to current flow. Indictors in series might be better but then you run the risk of 'radio' interference.

Being inefficient would presumably make it impossible to get enough brightness out of LEDs that fit into the lamp holder. The LEDs would get too hot trying to give out enough brightness for a car headlight.

However cars vary a lot, some are easy to detect flickering, some difficult, and some impossible (with the naked eye). Perhaps they just use a higher frequency?

Taillights are pretty bad on a lot of cars, as they dim the brakelights by deliberately flickering them.

 

[William Gothberg]

On Thu, 20 Dec 2018 04:34:08 -0000, Clare Snyder <clare@snyder.on.ca> wrote:

On Wed, 19 Dec 2018 19:34:57 -0000, "William Gothberg" <"William
Gothberg"@internet.co.is> wrote:

On Wed, 19 Dec 2018 18:03:19 -0000, Clark W. Griswold <clark.w.griswold@home.com> wrote:

On 12/19/2018 11:36 AM, William Gothberg wrote:
On Wed, 19 Dec 2018 16:18:29 -0000, Mark Lloyd <not@mail.invalid> 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)

I was assuming it was higher frequency than that, from the SMPS. But I'm thinking they don't have one - see my other reply where I used the camera on a long exposure.

> (also rules out the previously mentioned "engineer friend")

Who?

 

[William Gothberg]

On Thu, 20 Dec 2018 08:19:58 -0000, gregz <zekor@comcast.net> wrote:

Clare Snyder <clare@snyder.on.ca> wrote:
On Wed, 19 Dec 2018 19:34:57 -0000, "William Gothberg" <"William
Gothberg"@internet.co.is> wrote:

On Wed, 19 Dec 2018 18:03:19 -0000, Clark W. Griswold <clark.w.griswold@home.com> wrote:

On 12/19/2018 11:36 AM, William Gothberg wrote:
On Wed, 19 Dec 2018 16:18:29 -0000, Mark Lloyd <not@mail.invalid> 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.

 

[William Gothberg]

On Thu, 20 Dec 2018 07:09:59 -0000, Daniel60 <daniel47@eternal-september.org> wrote:

Mark Lloyd wrote on 20/12/2018 3:21 AM:
On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under
the LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.
... and, in real life, the Mag wheels of some cars seem to be spinning
backwards, dependant on the speed at which the car is travelling!!

In real life? I assume you mean under streetlighting. That effect can't occur with a steady lightsource such as the sun.

 

[William Gothberg]

On Thu, 20 Dec 2018 04:31:31 -0000, Clare Snyder <clare@snyder.on.ca> wrote:

On Wed, 19 Dec 2018 13:03:19 -0500, "Clark W. Griswold"
clark.w.griswold@home.com> wrote:

On 12/19/2018 11:36 AM, William Gothberg wrote:
On Wed, 19 Dec 2018 16:18:29 -0000, Mark Lloyd <not@mail.invalid> 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).

 

[William Gothberg]

On Thu, 20 Dec 2018 09:36:02 -0000, Jon Fairbairn <jon.fairbairn@cl.cam.ac.uk> wrote:

"William Gothberg" <"William Gothberg"@internet.co.is> writes:
Agreed. All I can detect (with my digital camera) is that
one brand of LED light I have flickers about 5 times less
(not sure if it's smother or faster) than the others.

Try a longer exposure and move the light rapidly relative to the
camera.

I wonder, if I fed the lamps with mains voltage DC, simply a bridge rectifier and a huge capacitor, they'd reduce their flicker. The cheap shit LED lamp I have that actually flashes at 100Hz would most likely get much brighter and burn out, so I'd have to adjust that, but the others which only flicker 8% would just get 4% brighter.

 

[William Gothberg]

On Thu, 20 Dec 2018 13:19:55 -0000, whisky-dave <whisky.dave@gmail.com> wrote:

On Thursday, 20 December 2018 13:00:02 UTC, William Gothberg wrote:
On Thu, 20 Dec 2018 09:36:02 -0000, Jon Fairbairn <jon.fairbairn@cl.cam.ac.uk> wrote:

"William Gothberg" <"William Gothberg"@internet.co.is> writes:
Agreed. All I can detect (with my digital camera) is that
one brand of LED light I have flickers about 5 times less
(not sure if it's smother or faster) than the others.

Try a longer exposure and move the light rapidly relative to the
camera.

I wonder, if I fed the lamps with mains voltage DC, simply a bridge rectifier and a huge capacitor,

No they'd probbaly blow up, don;t forget a bridge recifir would produce a voltage of at leat 330V and the power dissapated by each LED would also increase .

I thought about that, and the cheapest one, which seems to be just a bridge rectifier straight to the LEDs, would make them 65% brighter. But the others should only get 4% brighter. A switched mode supply fed by DC at the peak voltage of the mains, would still have its bulk capacitor at about the same voltage. It's already doing what I'm suggesting I do externally. They're rated at 85-260V, so I assume they're switched mode.

 

[William Gothberg]

On Thu, 20 Dec 2018 04:27:41 -0000, Clare Snyder <clare@snyder.on.ca> wrote:

On Wed, 19 Dec 2018 16:39:50 -0000, "William Gothberg" <"William
Gothberg"@internet.co.is> wrote:

On Wed, 19 Dec 2018 16:34:11 -0000, whisky-dave <whisky.dave@gmail.com> wrote:

On Wednesday, 19 December 2018 16:21:43 UTC, Mark Lloyd wrote:
On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under the
LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.

You can also observe such things using a smartphone that has a high FPS rate for recodring movie.
I can see the labs lights flicker when I film at 240FPS standard 60 and everything seems fine.

Everybody seems to constantly cut corners. Lights should just be on, no flicker at all. Fucking annoying if you have decent eyesight, I can see the flicker from almost everyone's LED tail lights.


This is sounding more and more like our "engineer friend" who needs
to do his own tire repairs and alignments and clutch repairs.

Don't know who you're referring to, but what's wrong with striving for perfection?

 

[William Gothberg]

On Thu, 20 Dec 2018 04:24:20 -0000, Clare Snyder <clare@snyder.on.ca> wrote:

On Thu, 20 Dec 2018 00:08:22 -0000, "William Gothberg" <"William
Gothberg"@internet.co.is> wrote:

On Wed, 19 Dec 2018 23:53:42 -0000, Rod Speed <rod.speed.aaa@gmail.com> wrote:



"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zt920ry6o5piw3@desktop-ga2mpl8.lan...
On Wed, 19 Dec 2018 16:21:41 -0000, Mark Lloyd <not@mail.invalid> wrote:

On 12/19/18 6:01 AM, William Gothberg wrote:

[snip]

They probably are fairly crude. I know they flicker, for example if I
use my cordless drill, the chuck appears to spin the wrong way under the
LED lighting.
I remember seeing that with a washing machine (under fluorescent
lights). As the tub was slowing down, the row of holes around the tub
would appear to reverse direction. Same thing with (spoked) wagon wheels
in movies.

It looks absolutely ridiculous with modern cars with LED headlights in
films. How hard can it be to put a smoothing capacitor on the output of
the power supply?

No point when the only thing that has a problem is videos.

You don't even see a problem with dashcams.

You should. Surely they operate in a similar way to movie cameras?


Different frame rates.

But unless they're identical to the LED flicker rate, you'd still see the effect.

 

[hah]

On 12/19/18 10:45 AM, Snicker wrote:

[snip]

Everybody seems to constantly cut corners. Lights should just be on, no flicker at all. Fucking annoying if you have decent eyesight, I can see the flicker from almost everyone's LED tail lights.

Then stop looking at them.

https://hitchhikers.fandom.com/wiki/Joo_Janta_200_Super-Chromatic_Peril_Sensitive_Sunglasses

--
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day).

"My other computer is a HOLMES IV ("High-Optional, Logical,
Multi-Evaluating Supervisor, Mark IV")"