Do switch mode power supplies flicker in time with mains?

[Mark Lloyd]

On 12/19/18 12:03 PM, Clark W. Griswold wrote:

[snip]

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?

And you'd have to isolate the lights from each other.

Since this landed in alt.home.repair, I gotta ask.  Do you have
single-phase or two-phase?

Normally, neighboring lights would be powered from the same phase.

--
5 days until the winter celebration (Tue Dec 25, 2018 12:00:00 AM for 1
day).

Mark Lloyd
http://notstupid.us/

"The Roman Catholic church, convinced that it is the only true church,
must demand the right to freedom for herself alone and the end of
freedom for all others." [Jesuit publication]

 

[William Gothberg]

On Thu, 20 Dec 2018 16:34:35 -0000, trader_4 <trader4@optonline.net> wrote:

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 <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).

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.

You would if it was a really shitty PSU with half wave rectification.

 

[William Gothberg]

On Thu, 20 Dec 2018 16:28:58 -0000, trader_4 <trader4@optonline.net> wrote:

On Thursday, December 20, 2018 at 8:45:58 AM UTC-5, William Gothberg wrote:
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?

There's a saying about that, "perfection is the enemy of good".
In this case that translates to it's a waste of time, money and
economically inefficient to fix things that aren't a problem.

It depends how far you take it. If I have a flickery light which gives me a headache, I'll alter the power supply to stop it doing so. If I have something which is noisy, I'll try to quieten it with lubrication or changing fans for quieter ones.

 

[William Gothberg]

On Thu, 20 Dec 2018 16:25:22 -0000, trader_4 <trader4@optonline.net> wrote:

On Thursday, December 20, 2018 at 7:29:53 AM UTC-5, William Gothberg wrote:
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.

Either you have eyes that are way more sensitive to this or you're in a
country that uses different car lights than here in the USA. There
are a lot of cars with LED lighting, headlights and rear lights, and
I've never noticed this flickering, nor have I ever heard it mentioned
before this thread. I haven't noticed flickering from any LED lights
I've used either.

I can see flicker on a 60Hz CRT monitor, but not on a 90Hz one, so that'll give you an idea on how good my eyes are.

Can you see flicker on tailliights if you scan your eyes across the scene?

 

[William Gothberg]

On Thu, 20 Dec 2018 04:03:06 -0000, Clare Snyder <clare@snyder.on.ca> wrote:

On Wed, 19 Dec 2018 12:49:47 -0000, "William Gothberg" <"William
Gothberg"@internet.co.is> wrote:

On Wed, 19 Dec 2018 12:28:04 -0000, Rod Speed <rod.speed.aaa@gmail.com> wrote:



"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zt9qc10co5piw3@desktop-ga2mpl8.lan...
On Wed, 19 Dec 2018 11:51:35 -0000, Rod Speed <rod.speed.aaa@gmail.com
wrote:

William Gothberg <"William Gothberg"@internet.co.is> wrote

Do switch mode power supplies flicker in time with mains?

No.

Specifically LED power supplies in commercially available domestic
lamps.

None of mine flicker at all.

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?

None of mine flicker at all.

And is there any way I can test this?

Yes, Get or make a strobe disk or use
one of the original LP disks that has
a strobe disk on it and see what it looks
like with the lights illuminating it. You'll
get it appearing to freeze when rotating
if the light level is varying in synch with
the mains frequency.

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.

Or they don't flicker at all. No reason why a proper
switched mode power supply needs to have any
AC component at all on its output. The cruder
ones may well do.

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.

But it's nothing like as low as 50Hz. What I want to know is if the
higher frequency they're flickering at is anchored with the rise of the AC
wave.

No its not.

I.e. will all the LED lights in the room flicker at precisely the same
time, or will they be out of synch (due to tolerances in the circuitry of
each PSU)

Due to it not being synched with the mains, actually.

I meant if the PSUs were absolutely identical, and all the lights were switched on at the same time (with one lightswitch), they should remain in synch forever. But since there are tolerances in all the components in the PSUs, they won't stay in time.

and fudge the brightness together.

Its not a fudge, it's the lack of synch.

I didn't mean fudge, I meant smudge.

And you should be able to see that by watching
the chuck as you move the drill between lights.
The rate and direction of rotation should change.

Only if the frequency is different, which I doubt as they are all the same model. What I need is a way of detecting if they're flashing together.

Why??? If the frequency is IDENTICAL (unlikely with production
"tolerances" of consumer grade SMPS wall warts) the chance of them
being EXACTLY in phase is remote at best as the "clock" trigger is
generally not based on the mains frequency. Even if they STARTED
exactly in phase, the frequency drift of the SMPS clock would take
them out of synch pretty quickly - and they would go in and out of
phase over time.

That's what I was asking, if the output frequency was synched to the mains frequency.

> And why do ypu NEED to know if they are synched? Just curious.

Because if I have several lights in one room, and they are out of sync, the flicker is less of a problem, as one will fill in the gaps of the other.

 

[William Gothberg]

On Thu, 20 Dec 2018 16:19:47 -0000, trader_4 <trader4@optonline.net> wrote:

On Wednesday, December 19, 2018 at 11:03:21 PM UTC-5, Clare Snyder wrote:
On Wed, 19 Dec 2018 12:49:47 -0000, "William Gothberg" <"William
Gothberg"@internet.co.is> wrote:

On Wed, 19 Dec 2018 12:28:04 -0000, Rod Speed <rod.speed.aaa@gmail.com> wrote:



"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zt9qc10co5piw3@desktop-ga2mpl8.lan...
On Wed, 19 Dec 2018 11:51:35 -0000, Rod Speed <rod.speed.aaa@gmail.com
wrote:

William Gothberg <"William Gothberg"@internet.co.is> wrote

Do switch mode power supplies flicker in time with mains?

No.

Specifically LED power supplies in commercially available domestic
lamps.

None of mine flicker at all.

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?

None of mine flicker at all.

And is there any way I can test this?

Yes, Get or make a strobe disk or use
one of the original LP disks that has
a strobe disk on it and see what it looks
like with the lights illuminating it. You'll
get it appearing to freeze when rotating
if the light level is varying in synch with
the mains frequency.

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.

Or they don't flicker at all. No reason why a proper
switched mode power supply needs to have any
AC component at all on its output. The cruder
ones may well do.

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.

But it's nothing like as low as 50Hz. What I want to know is if the
higher frequency they're flickering at is anchored with the rise of the AC
wave.

No its not.

I.e. will all the LED lights in the room flicker at precisely the same
time, or will they be out of synch (due to tolerances in the circuitry of
each PSU)

Due to it not being synched with the mains, actually.

I meant if the PSUs were absolutely identical, and all the lights were switched on at the same time (with one lightswitch), they should remain in synch forever. But since there are tolerances in all the components in the PSUs, they won't stay in time.


Forget the component tolerances. Two mechanical light switches can't be
synced to turn on the power at exactly the same time, anywhere close
enough to sync them up to begin with.

Er.... I have more than one light running off one switch, many people do. A large room normally has more than one light fixture, or a fixture with several bulbs in it.

You would need electronic
switches driven by a common signal. And even then, even with components
of sufficient tolerance, which is impossible, I'm not sure it would work.
First thing that comes to mind is the freq source, which I'm guessing
is a crystal. You could have crystals with theoretically identical
frequencies, but I'm not sure that means they will start oscillating
at exactly the same instant so there is no phase difference.

 

[William Gothberg]

On Thu, 20 Dec 2018 17:13:52 -0000, trader_4 <trader4@optonline.net> wrote:

On Thursday, December 20, 2018 at 12:07:40 PM UTC-5, William Gothberg wrote:
On Thu, 20 Dec 2018 16:25:22 -0000, trader_4 <trader4@optonline.net> wrote:

On Thursday, December 20, 2018 at 7:29:53 AM UTC-5, William Gothberg wrote:
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.

Either you have eyes that are way more sensitive to this or you're in a
country that uses different car lights than here in the USA. There
are a lot of cars with LED lighting, headlights and rear lights, and
I've never noticed this flickering, nor have I ever heard it mentioned
before this thread. I haven't noticed flickering from any LED lights
I've used either.

I can see flicker on a 60Hz CRT monitor, but not on a 90Hz one, so that'll give you an idea on how good my eyes are.

Can you see flicker on tailliights if you scan your eyes across the scene?

Like I said, I haven't noticed it in the driving I've done. Nor have I
heard anyone else mention it. Next time I come across a car that has
LEDs I'll look more closely and see if I can see anything. If just
scanning reveals it, you;d think a lot of people would be noticing it.
Scanning is a part of driving.

I'd estimate about 1 in 5 people can see it, similar to how many can see flicker on a 60Hz CRT computer monitor.

Don't most cars have LEDs now? Or does your area have a lot of older cars? People (stupidly) around here seem to like cars that are no more than 10 years old. I don't think many cars after 2008 had bulbs.

Searching for "LED tail light flicker" without the quotes in google produces 4.5 million results!

 

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubl67f1o5piw3@desktop-ga2mpl8.lan...

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?

Yep. those will have simple capacitance droppers.

 

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubminnfo5piw3@desktop-ga2mpl8.lan...

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.

No point in doing that.

 

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubnqbkho5piw3@desktop-ga2mpl8.lan...

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.

Wont work at all if they use capacitor droppers and
they very likely do because those are the only cheap
droppers for dropping such a large voltage.

Very easy to try tho and see if it works.

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.

 

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubprsfco5piw3@desktop-ga2mpl8.lan...

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.

Not necessarily. Its quite possible to do a capacitor dropper powering
a current regulator that way. Have a look a Big Clive's teardowns.

 

[Rod Speed]

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubpuunso5piw3@desktop-ga2mpl8.lan...

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?

It increases costs for everyone who isnt a freak.

 

[Rod Speed]

"Mark Lloyd" <not@mail.invalid> wrote in message
news:mXNSD.61224$gU6.23879@fx33.iad...

On 12/19/18 12:03 PM, Clark W. Griswold wrote:

[snip]

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?

And you'd have to isolate the lights from each other.

Since this landed in alt.home.repair, I gotta ask. Do you have
single-phase or two-phase?

Normally, neighboring lights would be powered from the same phase.

Mine arent and that is deliberate so that if I lose a single phase, and
that isnt that uncommon, I don't lose all the lights in the one area.

 

[Peeler]

On Fri, 21 Dec 2018 05:50:23 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

Yep. those will have simple capacitance droppers.

Those could never be as simple as the "brains" of you two prize idiots! <BG>

--
Richard addressing Rot Speed:
"Shit you're thick/pathetic excuse for a troll."
MID: <ogoa38$pul$1@news.mixmin.net>

 

[Peeler]

On Fri, 21 Dec 2018 06:24:19 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

Not necessarily. Its quite possible to do a capacitor dropper powering
a current regulator that way. Have a look a Big Clive's teardowns.

It seems to be quite impossible to separate you two congenital idiots with a
crowbar even! LOL

--
FredXX to Rot Speed:
"You are still an idiot and an embarrassment to your country. No wonder
we shippe the likes of you out of the British Isles. Perhaps stupidity
and criminality is inherited after all?"
Message-ID: <plbf76$gfl$1@dont-email.me>

 

[Peeler]

On Fri, 21 Dec 2018 06:11:36 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:


> Very easy to try tho and see if it works.

Wot? And then not being able to keep baiting you senile idiots anymore? 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>

 

[William Gothberg]

On Thu, 20 Dec 2018 19:11:36 -0000, Rod Speed <rod.speed.aaa@gmail.com> wrote:

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubnqbkho5piw3@desktop-ga2mpl8.lan...
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.

Wont work at all if they use capacitor droppers and

I made a few of those to power LEDs to indicate the function of my central heating. I'm looking inside the flickery lamp just now (Ł15, 20W). Without undoing the glue holding the PSU onto the inside of it, all I can see is probably: the mains going through a large bipolar cap, a tiny resistor (to discharge it safely?), a bridge rectifier, another very large resister (to limit the LED current more accurately?), then a 400V 4.7uF capacitor (which is bulged). A capacitor dropper with a rectifier and smoothing capacitor after it? The one I made has no smoothing cap, just mains to cap to resistor to bridge to LED. Perhaps this bulged cap is why I'm getting flicker, I'll try replacing it tomorrow.

they very likely do because those are the only cheap
droppers for dropping such a large voltage.

Aren't miniature SMPS units pretty cheap? I just bought a 12V 6A SMPS for Ł4.50. Designed for powering LEDs - but I've looked inside it and it's definitely a switched mode, not a capacitor dropper. Now this flickery LED lamp I'm looking inside, it's about 20W, so 12V at 2A is all that's required, it could have had an SMPS in it similar to the one I just described.

I'm now looking inside one of the better LED lamps (the non-flickery model). It has a basic SMPS inside it. They're 9W and Ł4 each for the whole lamp. I'm sure it's more than just a standard SMPS though, because when some LEDs fail short circuit (it has about 40 in series), the voltage coming from the PSU drops, to maintain the correct current for the remaining good LEDs.

> Very easy to try tho and see if it works.

Looks like it would help the better ones, but not the crap one. Better (as I only have a few crap ones) to stick a bigger smoothing cap inside those. For the good ones, the only problem I can foresee with the external smoother, is overloading the lamp's bridge rectifier, as it will only be conducting on two of the four diodes.

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.

 

[%]

On 2018-12-20 1:30 p.m., William Gothberg wrote:

On Thu, 20 Dec 2018 19:11:36 -0000, Rod Speed <rod.speed.aaa@gmail.com
wrote:

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubnqbkho5piw3@desktop-ga2mpl8.lan...
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.

Wont work at all if they use capacitor droppers and

I made a few of those to power LEDs to indicate the function of my
central heating.  I'm looking inside the flickery lamp just now (Ł15,
20W).  Without undoing the glue holding the PSU onto the inside of it,
all I can see is probably: the mains going through a large bipolar cap,
a tiny resistor (to discharge it safely?), a bridge rectifier, another
very large resister (to limit the LED current more accurately?), then a
400V 4.7uF capacitor (which is bulged).  A capacitor dropper with a
rectifier and smoothing capacitor after it?  The one I made has no
smoothing cap, just mains to cap to resistor to bridge to LED.  Perhaps
this bulged cap is why I'm getting flicker, I'll try replacing it tomorrow.

they very likely do because those are the only cheap
droppers for dropping such a large voltage.

Aren't miniature SMPS units pretty cheap?  I just bought a 12V 6A SMPS
for Ł4.50.  Designed for powering LEDs - but I've looked inside it and
it's definitely a switched mode, not a capacitor dropper.  Now this
flickery LED lamp I'm looking inside, it's about 20W, so 12V at 2A is
all that's required, it could have had an SMPS in it similar to the one
I just described.

I'm now looking inside one of the better LED lamps (the non-flickery
model).  It has a basic SMPS inside it.  They're 9W and Ł4 each for the
whole lamp.  I'm sure it's more than just a standard SMPS though,
because when some LEDs fail short circuit (it has about 40 in series),
the voltage coming from the PSU drops, to maintain the correct current
for the remaining good LEDs.

Very easy to try tho and see if it works.

Looks like it would help the better ones, but not the crap one.  Better
(as I only have a few crap ones) to stick a bigger smoothing cap inside
those.  For the good ones, the only problem I can foresee with the
external smoother, is overloading the lamp's bridge rectifier, as it
will only be conducting on two of the four diodes.

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.

you could use being 4 % brighter

 

[William Gothberg]

On Thu, 20 Dec 2018 20:40:26 -0000, % <persent@gmail.com> wrote:

On 2018-12-20 1:30 p.m., William Gothberg wrote:
On Thu, 20 Dec 2018 19:11:36 -0000, Rod Speed <rod.speed.aaa@gmail.com
wrote:

"William Gothberg" <"William Gothberg"@internet.co.is> wrote in message
newsp.zubnqbkho5piw3@desktop-ga2mpl8.lan...
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.

Wont work at all if they use capacitor droppers and

I made a few of those to power LEDs to indicate the function of my
central heating. I'm looking inside the flickery lamp just now (Ł15,
20W). Without undoing the glue holding the PSU onto the inside of it,
all I can see is probably: the mains going through a large bipolar cap,
a tiny resistor (to discharge it safely?), a bridge rectifier, another
very large resister (to limit the LED current more accurately?), then a
400V 4.7uF capacitor (which is bulged). A capacitor dropper with a
rectifier and smoothing capacitor after it? The one I made has no
smoothing cap, just mains to cap to resistor to bridge to LED. Perhaps
this bulged cap is why I'm getting flicker, I'll try replacing it tomorrow.

they very likely do because those are the only cheap
droppers for dropping such a large voltage.

Aren't miniature SMPS units pretty cheap? I just bought a 12V 6A SMPS
for Ł4.50. Designed for powering LEDs - but I've looked inside it and
it's definitely a switched mode, not a capacitor dropper. Now this
flickery LED lamp I'm looking inside, it's about 20W, so 12V at 2A is
all that's required, it could have had an SMPS in it similar to the one
I just described.

I'm now looking inside one of the better LED lamps (the non-flickery
model). It has a basic SMPS inside it. They're 9W and Ł4 each for the
whole lamp. I'm sure it's more than just a standard SMPS though,
because when some LEDs fail short circuit (it has about 40 in series),
the voltage coming from the PSU drops, to maintain the correct current
for the remaining good LEDs.

Very easy to try tho and see if it works.

Looks like it would help the better ones, but not the crap one. Better
(as I only have a few crap ones) to stick a bigger smoothing cap inside
those. For the good ones, the only problem I can foresee with the
external smoother, is overloading the lamp's bridge rectifier, as it
will only be conducting on two of the four diodes.

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.

you could use being 4 % brighter

That would make my IQ 140.

Was the above too difficult for you to discuss?

 

[Peeler]

On Fri, 21 Dec 2018 07:02:05 +1100, cantankerous trolling geezer Rot Speed,
the auto-contradicting senile sociopath, blabbered, again:

Mine arent and that is deliberate so that if I lose a single phase,

You'd better worry about losing your one single brain cell, senile Rot! 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>