"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage, but I
live opposite the substation so it's higher than the rest of the street,
and they won't do anything about it. I consequently run my computer,
lights, etc off a UPS, which automatically chops 10 or 20V off when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware that I
don't earth them. A couple of them made a humming noise when I did. If
I
touch the metal casing of an unearthed unit, and rub my finger along it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when earthed.
Easy to measure.

On Thu, 3 Oct 2019 06:37:34 -0700 (PDT), whisky-dave
wrote:

On Thursday, 3 October 2019 14:29:30 UTC+1, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because they're inefficient".

That is the technical answer just lioke why does a wire get hot when curremnt passes through it.

And will we ever make them more efficient?

Probably.


If you plot voltage across the LED versus current through it, the
curve is not linear like a resistor. At low voltage it hardly
conducts, but at higher voltage it conducts a lot, and the curve
flattens like a not very good zener diode, limiting the voltage.

Voltage times current equals watts i.e. heat plus a little light.
Light has a power but it's miniscule. Complicated physics theory might
explain how the light is produced and why so little of it, but we
lesser mortals wouldn't be able to understand it.
--
Dave W

On 04/10/2019 23:54, Dave W wrote:
Light has a power but it's miniscule.

No, it isnt.

Solar panels at midday work.
Sunlight in the tropics at midday us around 1KW/sq m.


Complicated physics theory might
explain how the light is produced and why so little of it,

It isn in the case of LEDS quite a lot. IIRC 10% efficient or thereabouts.

the current knock electrons into higher orbits, as they fall back they
emit photons.

but we
lesser mortals wouldn't be able to understand it.

Nobody understands anything completely


--
There is something fascinating about science. One gets such wholesale
returns of conjecture out of such a trifling investment of fact.

Mark Twain

On Sat, 5 Oct 2019 08:46:55 +1000, AlexK, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


The type of motor used in those has tho. Far fewer of the original
motors with a power factor problem now in domestic appliances.

You STILL believe you might win this game, my senile punching bag? ****ing
HILARIOUS! LOL

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On Sat, 5 Oct 2019 08:49:23 +1000, AlexK, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


That's more likely to be due to a significant earth current when earthed.
Easy to measure.

Let's all hope there will soon be two meters of earth on top of you, you
85-year-old trolling senile asshole!

--
Richard addressing Rot Speed:
"**** you're thick/pathetic excuse for a troll."
MID:

On Fri, 04 Oct 2019 23:46:55 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 19:17:46 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

Is power factor that important? In a domestic building, you are not
billed for power factor. I might have a capacitive load, but my
neighbour
has an inductive load, so they even out.

Most neighbours don't have much long term inductive load anymore.

I don't see why it would have reduced.

It has anyway.

For what reason Mr Speed? You ain't fooling me.

Inductive load is from motors - mowers, washing machines, vacuum cleaners,
etc. This hasn't changed.

The type of motor used in those has tho. Far fewer of the original
motors with a power factor problem now in domestic appliances.

Ah, so you answered it here instead of up there where you interrupted. FFS.

On Fri, 04 Oct 2019 23:49:23 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage, but I
live opposite the substation so it's higher than the rest of the street,
and they won't do anything about it. I consequently run my computer,
lights, etc off a UPS, which automatically chops 10 or 20V off when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware that I
don't earth them. A couple of them made a humming noise when I did. If
I
touch the metal casing of an unearthed unit, and rub my finger along it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when earthed.
Easy to measure.

0.020mA per foot of lighting (they're 4.5W per foot). I don't call that significant and can't see how it would cause an audible vibration.

On Fri, 04 Oct 2019 23:54:39 +0100, Dave W wrote:

On Thu, 3 Oct 2019 06:37:34 -0700 (PDT), whisky-dave
wrote:

On Thursday, 3 October 2019 14:29:30 UTC+1, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because they're inefficient".

That is the technical answer just lioke why does a wire get hot when curremnt passes through it.

And will we ever make them more efficient?

Probably.

If you plot voltage across the LED versus current through it, the
curve is not linear like a resistor. At low voltage it hardly
conducts, but at higher voltage it conducts a lot, and the curve
flattens like a not very good zener diode, limiting the voltage.

It only limits it for a while, then you get smoke.

Voltage times current equals watts i.e. heat plus a little light.
Light has a power but it's miniscule. Complicated physics theory might
explain how the light is produced and why so little of it, but we
lesser mortals wouldn't be able to understand it.

I always thought an incandescent bulb was 1% light, 99% heat.
A fluorescent tube was 5% light, 95% heat.
And an LED was 10% light, 90% heat.

As a ratio those are about right. 100W tungsten = 20W fluorescent = 10W LED.

But I've been told elsewhere that LEDs are 40% efficient.

On 10/4/19 2:51 PM, Commander Kinsey wrote:

[snip]

I have a LED

That irritates me, why don't you write "an LED"?* How do you say "LED"?
I say "Ell Eee Dee", not "Light Emitting Diode".* So it needs an "an",
not an "a".

"an LED" irritates me. I know the word is "light".

bulb (60W equivalent) in a lamp here.

60W?* Are you a Klingon and love darkness?* I use 100W and 150W bulbs
only.* And lots of them.* My living room (7 metres by 4 metres) contains
13 90W bulbs.

It also matters if the light source is in the right place, like from
behind is good if you're reading or watching TV.

Some people think more light is always better. I remember working behind
a TV (26-inch CRT console), where I could see OK. Then someone, trying
to be helpful, turned on a nearby wall lamp. The effect of that is that
the area behind the TV became completely BLACK.

[snip]

--
81 days until the winter celebration (Wed, Dec 25, 2019 12:00:00 AM for
1 day).

Mark Lloyd
http://notstupid.us/

"Tinnitus is a pain in the neck"

On Sat, 05 Oct 2019 19:46:08 +0100, Mark Lloyd wrote:

On 10/4/19 2:51 PM, Commander Kinsey wrote:

[snip]

I have a LED

That irritates me, why don't you write "an LED"? How do you say "LED"?
I say "Ell Eee Dee", not "Light Emitting Diode". So it needs an "an",
not an "a".

"an LED" irritates me. I know the word is "light".

But which would you say if you read the sentence out loud? Do you say the letters like me, or do you say the full words? I say "DVLA" not "Driver and Vehicle Licensing Authority"

bulb (60W equivalent) in a lamp here.

60W? Are you a Klingon and love darkness? I use 100W and 150W bulbs
only. And lots of them. My living room (7 metres by 4 metres) contains
13 90W bulbs.

It also matters if the light source is in the right place, like from
behind is good if you're reading or watching TV.

I prefer the whole room to be evenly lit.

Some people think more light is always better. I remember working behind
a TV (26-inch CRT console), where I could see OK. Then someone, trying
to be helpful, turned on a nearby wall lamp. The effect of that is that
the area behind the TV became completely BLACK.

More light is better if the whole room is lit evenly. Which is why I prefer strip lights to point sources. Much better if you're soldering for example, you don't create shadows, as light can come to the workpiece from all angles, no matter where your body/head/hands/tools are.

On Sat, 5 Oct 2019 13:46:08 -0500, Mark Lloyd, another absolutely brain
dead, troll-feeding, senile cretin, drivelled:


"an LED" irritates me. I know the word is "light".

You must about as big an idiot as the retarded troll you keep feeding,
senile cretin! LOL

"Mark Lloyd" wrote in message
...
On 10/4/19 2:51 PM, Commander Kinsey wrote:

I have a LED

That irritates me, why don't you write "an LED"? How do you say "LED"?
I say "Ell Eee Dee", not "Light Emitting Diode". So it needs an "an",
not an "a".

"an LED" irritates me. I know the word is "light".

I think it is normal convention that an initialism that starts with a *vowel
sound* takes "an", on the grounds of euphony: that in normal English, you
never precede a word that starts with a vowel sound with "a".

Hence an apple, but a uniform. A hedge or a hotel or a historic event but an
honourable occasion (H is sounded for the first three but silent for the
last one). For some reason, it considered "better" to use "an" before hotel
and historic, even though the H is sounded. That sounds as daft to my ears
as "an spoon" - it's not a vowel sound so you use "a". I could understand if
people pronounce hotel the French way, but it needs to be consistent: "an
'otel" or "a hotel".


As regards initialisms/abbreviations, you do get anomalies like "an LED"
(ell-ee-dee) that starts with a consonant but "a UFO" (you-eff-oh) that
starts with a vowel pronounced as a consonant.

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 19:46:08 +0100, Mark Lloyd wrote:

On 10/4/19 2:51 PM, Commander Kinsey wrote:
bulb (60W equivalent) in a lamp here.

60W? Are you a Klingon and love darkness? I use 100W and 150W bulbs
only. And lots of them. My living room (7 metres by 4 metres) contains
13 90W bulbs.

It also matters if the light source is in the right place, like from
behind is good if you're reading or watching TV.

I prefer the whole room to be evenly lit.

Some people think more light is always better. I remember working behind
a TV (26-inch CRT console), where I could see OK. Then someone, trying
to be helpful, turned on a nearby wall lamp. The effect of that is that
the area behind the TV became completely BLACK.

More light is better if the whole room is lit evenly. Which is why I
prefer strip lights to point sources. Much better if you're soldering for
example, you don't create shadows, as light can come to the workpiece from
all angles, no matter where your body/head/hands/tools are.


Exactly. It is the use that you are making of the light which governs
whether you want a point source and directional lighting, or a diffuse
light.

I prefer to read with a light over my shoulder to light the pages of the
book, but with the rest of the room dark enough than I'm not distracted by
everything else around the book. Likewise for watching TV - screen brighter
than ambient light, even if the ambient light isn't reducing screen contrast
by brightening the dark parts of it.


My wife prefers uniform lighting - even if that means you are looking into
the light. When reading in bed, she will turn on the overhead light (single
ceiling rose or lots of GU10 spotlights) which illuminate the rest of the
room and shine right in your face, but leave the pages of the book in
shadow, She believes that reading by over-the-shoulder light, with the book
brighter than the background, strains your eyes.

On Sat, 5 Oct 2019 20:33:14 +0100, NY, the notorious, troll-feeding,
endlessly blathering senile idiot, blathered again:



My wife prefers uniform lighting

You got a "wife", troll-feeding senile idiot? Does she know about you
sucking troll cock on Usenet on every occasion? BG

On Sat, 05 Oct 2019 20:23:02 +0100, NY wrote:

"Mark Lloyd" wrote in message
...
On 10/4/19 2:51 PM, Commander Kinsey wrote:

I have a LED

That irritates me, why don't you write "an LED"? How do you say "LED"?
I say "Ell Eee Dee", not "Light Emitting Diode". So it needs an "an",
not an "a".

"an LED" irritates me. I know the word is "light".

I think it is normal convention that an initialism that starts with a *vowel
sound* takes "an", on the grounds of euphony: that in normal English, you
never precede a word that starts with a vowel sound with "a".

Hence an apple, but a uniform. A hedge or a hotel or a historic event but an
honourable occasion (H is sounded for the first three but silent for the
last one). For some reason, it considered "better" to use "an" before hotel
and historic, even though the H is sounded. That sounds as daft to my ears
as "an spoon" - it's not a vowel sound so you use "a". I could understand if
people pronounce hotel the French way, but it needs to be consistent: "an
'otel" or "a hotel".

My god! I agree with you completely. I was about to say the same thing as soon as you wrote "a historic event", it's really grating to my ears to hear an historic.

Also, Americans get the Hs wrong. Like erb, as in marijuana. An 'erb would be fine, but they think the H is always silent.

As regards initialisms/abbreviations, you do get anomalies like "an LED"
(ell-ee-dee) that starts with a consonant but "a UFO" (you-eff-oh) that
starts with a vowel pronounced as a consonant.

I say "a URL" for a web address, but I knew someone who said "an url", as in how you would pronounce "hurl" with a silent H. He insisted that acronyms should be pronounced like words. WLED became "well-ed", as in "well" followed by the name "Ed". I assume because pronouncing a W before an L was too difficult, so he then added extra vowels.

On Sat, 05 Oct 2019 20:33:14 +0100, NY wrote:

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 19:46:08 +0100, Mark Lloyd wrote:

On 10/4/19 2:51 PM, Commander Kinsey wrote:
bulb (60W equivalent) in a lamp here.

60W? Are you a Klingon and love darkness? I use 100W and 150W bulbs
only. And lots of them. My living room (7 metres by 4 metres) contains
13 90W bulbs.

It also matters if the light source is in the right place, like from
behind is good if you're reading or watching TV.

I prefer the whole room to be evenly lit.

Some people think more light is always better. I remember working behind
a TV (26-inch CRT console), where I could see OK. Then someone, trying
to be helpful, turned on a nearby wall lamp. The effect of that is that
the area behind the TV became completely BLACK.

More light is better if the whole room is lit evenly. Which is why I
prefer strip lights to point sources. Much better if you're soldering for
example, you don't create shadows, as light can come to the workpiece from
all angles, no matter where your body/head/hands/tools are.


Exactly. It is the use that you are making of the light which governs
whether you want a point source and directional lighting, or a diffuse
light.

I prefer to read with a light over my shoulder to light the pages of the
book, but with the rest of the room dark enough than I'm not distracted by
everything else around the book. Likewise for watching TV - screen brighter
than ambient light, even if the ambient light isn't reducing screen contrast
by brightening the dark parts of it.

I always like everything lit in the room, or I doze off.

My wife prefers uniform lighting - even if that means you are looking into
the light. When reading in bed, she will turn on the overhead light (single
ceiling rose or lots of GU10 spotlights) which illuminate the rest of the
room and shine right in your face, but leave the pages of the book in
shadow, She believes that reading by over-the-shoulder light, with the book
brighter than the background, strains your eyes.

That may be true, and why I feel sleepy if I do so. But then some people read to get to sleep.

On 2019-10-05 12:48 p.m., Commander Kinsey wrote:
On Sat, 05 Oct 2019 20:33:14 +0100, NY wrote:

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 19:46:08 +0100, Mark Lloyd wrote:

On 10/4/19 2:51 PM, Commander Kinsey wrote:
bulb (60W equivalent) in a lamp here.

60W?* Are you a Klingon and love darkness?* I use 100W and 150W bulbs
only.* And lots of them.* My living room (7 metres by 4 metres)
contains
13 90W bulbs.

It also matters if the light source is in the right place, like from
behind is good if you're reading or watching TV.

I prefer the whole room to be evenly lit.

Some people think more light is always better. I remember working
behind
a TV (26-inch CRT console), where I could see OK. Then someone, trying
to be helpful, turned on a nearby wall lamp. The effect of that is that
the area behind the TV became completely BLACK.

More light is better if the whole room is lit evenly.* Which is why I
prefer strip lights to point sources.* Much better if you're
soldering for
example, you don't create shadows, as light can come to the workpiece
from
all angles, no matter where your body/head/hands/tools are.


Exactly. It is the use that you are making of the light which governs
whether you want a point source and directional lighting, or a diffuse
light.

I prefer to read with a light over my shoulder to light the pages of the
book, but with the rest of the room dark enough than I'm not
distracted by
everything else around the book. Likewise for watching TV - screen
brighter
than ambient light, even if the ambient light isn't reducing screen
contrast
by brightening the dark parts of it.

I always like everything lit in the room, or I doze off.

My wife prefers uniform lighting - even if that means you are looking
into
the light. When reading in bed, she will turn on the overhead light
(single
ceiling rose or lots of GU10 spotlights) which illuminate the rest of the
room and shine right in your face, but leave the pages of the book in
shadow, She believes that reading by over-the-shoulder light, with the
book
brighter than the background, strains your eyes.

That may be true, and why I feel sleepy if I do so.* But then some
people read to get to sleep.

i have sex to fall asleep and i don't care what the lights are doing

"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 23:46:55 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 19:17:46 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

Is power factor that important? In a domestic building, you are not
billed for power factor. I might have a capacitive load, but my
neighbour
has an inductive load, so they even out.

Most neighbours don't have much long term inductive load anymore.

I don't see why it would have reduced.

It has anyway.

For what reason

To get better motors, direct drive etc with washing machines for example.

Inductive load is from motors - mowers, washing machines, vacuum
cleaners,
etc. This hasn't changed.

The type of motor used in those has tho. Far fewer of the original
motors with a power factor problem now in domestic appliances.

"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 23:49:23 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage, but
I
live opposite the substation so it's higher than the rest of the
street,
and they won't do anything about it. I consequently run my computer,
lights, etc off a UPS, which automatically chops 10 or 20V off when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware that
I
don't earth them. A couple of them made a humming noise when I did.
If
I
touch the metal casing of an unearthed unit, and rub my finger along
it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when earthed.
Easy to measure.

0.020mA per foot of lighting (they're 4.5W per foot). I don't call that
significant and can't see how it would cause an audible vibration.

Yeah, its more likely to be caused by something else.

Maybe its just not got the internal high frequency transformer potted
or mounted properly and you get resonance effect with the frequency
changing a little when its earthed so that you get the resonance effect
at that slightly different frequency.

On Sun, 6 Oct 2019 07:17:00 +1100, AlexK, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


To get better motors, direct drive etc with washing machines for example.

Senile Rodent knows EVERYTHING, doesn't he, senile Rodent? LOL

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On Sun, 6 Oct 2019 07:22:03 +1100, AlexK, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:


Maybe its just not got the internal high frequency transformer potted
or mounted properly and you get resonance effect with the frequency
changing a little when its earthed so that you get the resonance effect
at that slightly different frequency.

Maybe not, driveling senile idiot!

--
Website (from 2007) dedicated to the 85-year-old trolling senile
cretin from Oz:
https://www.pcreview.co.uk/threads/r...d-faq.2973853/

On Sat, 05 Oct 2019 21:17:00 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 23:46:55 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:17:46 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

Is power factor that important? In a domestic building, you are not
billed for power factor. I might have a capacitive load, but my
neighbour
has an inductive load, so they even out.

Most neighbours don't have much long term inductive load anymore.

I don't see why it would have reduced.

It has anyway.

For what reason

To get better motors, direct drive etc with washing machines for example.

What has direct drive got to do with power factor?

Direct drive motors are interesting - I once had a very cheap turntable that said "direct drive", so I guess it's not always a good thing?

From Wikipedia: "Usually motors are built to achieve maximum torque at high rotational speeds, usually 1500 or 3000 rpm."
I thought motors produced more torque when slower - which is why they burn out when jammed.

On Sat, 05 Oct 2019 21:22:03 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 23:49:23 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage, but
I
live opposite the substation so it's higher than the rest of the
street,
and they won't do anything about it. I consequently run my computer,
lights, etc off a UPS, which automatically chops 10 or 20V off when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware that
I
don't earth them. A couple of them made a humming noise when I did.
If
I
touch the metal casing of an unearthed unit, and rub my finger along
it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when earthed.
Easy to measure.

0.020mA per foot of lighting (they're 4.5W per foot). I don't call that
significant and can't see how it would cause an audible vibration.

Yeah, its more likely to be caused by something else.

Maybe its just not got the internal high frequency transformer potted
or mounted properly and you get resonance effect with the frequency
changing a little when its earthed so that you get the resonance effect
at that slightly different frequency.

I can't remember what the frequency I heard was, but it wasn't that high, probably something like 1 kHz. Aren't the transformers way higher than that?

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 21:17:00 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 23:46:55 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:17:46 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF
of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

Is power factor that important? In a domestic building, you are not
billed for power factor. I might have a capacitive load, but my
neighbour
has an inductive load, so they even out.

Most neighbours don't have much long term inductive load anymore.

I don't see why it would have reduced.

It has anyway.

For what reason

To get better motors, direct drive etc with washing machines for example.

What has direct drive got to do with power factor?

They arent the old induction motors with the power factor they had.

Direct drive motors are interesting - I once had a very cheap turntable
that said "direct drive", so I guess it's not always a good thing?

There's a big difference between a turntable motor and
one in a top loading washing machine which needs to
do a variety of different things when washing, adjitating
and spin drying at different speeds.

From Wikipedia: "Usually motors are built to achieve maximum torque at
high rotational speeds, usually 1500 or 3000 rpm."
I thought motors produced more torque when slower - which is why they burn
out when jammed.

Not relevant to what is being discussed, the power factor.

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 21:22:03 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Fri, 04 Oct 2019 23:49:23 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF
of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor
of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage,
but
I
live opposite the substation so it's higher than the rest of the
street,
and they won't do anything about it. I consequently run my
computer,
lights, etc off a UPS, which automatically chops 10 or 20V off when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware
that
I
don't earth them. A couple of them made a humming noise when I did.
If
I
touch the metal casing of an unearthed unit, and rub my finger along
it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated
stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when
earthed.
Easy to measure.

0.020mA per foot of lighting (they're 4.5W per foot). I don't call that
significant and can't see how it would cause an audible vibration.

Yeah, its more likely to be caused by something else.

Maybe its just not got the internal high frequency transformer potted
or mounted properly and you get resonance effect with the frequency
changing a little when its earthed so that you get the resonance effect
at that slightly different frequency.

I can't remember what the frequency I heard was, but it wasn't that high,
probably something like 1 kHz. Aren't the transformers way higher than
that?

Yes, but the noise frequency is determined by the mechanical
resonant frequency of the mechanical stuff, not the frequency
of the current thru the transformer. In other words it can be
way lower than the frequency of the current. A sub harmonic in fact.

On Sat, 05 Oct 2019 22:15:34 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 21:17:00 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 23:46:55 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:17:46 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF
of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

Is power factor that important? In a domestic building, you are not
billed for power factor. I might have a capacitive load, but my
neighbour
has an inductive load, so they even out.

Most neighbours don't have much long term inductive load anymore.

I don't see why it would have reduced.

It has anyway.

For what reason

To get better motors, direct drive etc with washing machines for example.

What has direct drive got to do with power factor?

They arent the old induction motors with the power factor they had.

I thought all motors created the same inductive load, and had to be compensated for if you wanted unity PF.

Direct drive motors are interesting - I once had a very cheap turntable
that said "direct drive", so I guess it's not always a good thing?

There's a big difference between a turntable motor and
one in a top loading washing machine which needs to
do a variety of different things when washing, adjitating
and spin drying at different speeds.

I know. Which makes me think it's important for a washing machine. But on a turntable, it has to be a very precise speed or the music sounds ****. It's the last place I'd think of putting one.

Actually I think I remembered wrong, the cheap stereo might have said "belt drive" on the front. Direct drive could have been the decent one.

From Wikipedia: "Usually motors are built to achieve maximum torque at
high rotational speeds, usually 1500 or 3000 rpm."
I thought motors produced more torque when slower - which is why they burn
out when jammed.

Not relevant to what is being discussed, the power factor.

Aren't I allowed to drift the conversation a little?

On Sat, 05 Oct 2019 22:18:44 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 21:22:03 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 23:49:23 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because
they're inefficient". And will we ever make them more efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF
of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor
of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage,
but
I
live opposite the substation so it's higher than the rest of the
street,
and they won't do anything about it. I consequently run my
computer,
lights, etc off a UPS, which automatically chops 10 or 20V off when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware
that
I
don't earth them. A couple of them made a humming noise when I did.
If
I
touch the metal casing of an unearthed unit, and rub my finger along
it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated
stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when
earthed.
Easy to measure.

0.020mA per foot of lighting (they're 4.5W per foot). I don't call that
significant and can't see how it would cause an audible vibration.

Yeah, its more likely to be caused by something else.

Maybe its just not got the internal high frequency transformer potted
or mounted properly and you get resonance effect with the frequency
changing a little when its earthed so that you get the resonance effect
at that slightly different frequency.

I can't remember what the frequency I heard was, but it wasn't that high,
probably something like 1 kHz. Aren't the transformers way higher than
that?

Yes, but the noise frequency is determined by the mechanical
resonant frequency of the mechanical stuff, not the frequency
of the current thru the transformer. In other words it can be
way lower than the frequency of the current. A sub harmonic in fact.

Ah, that makes sense. So I guess I could also fix it by simply sticking a small weight on the device, like a lump of blutack, which would lower the resonant frequency of the casing. But is it the casing that's vibrating?

On Sun, 6 Oct 2019 08:15:34 +1100, AlexKcantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

FLUSH 82 lines of the clinically insane sociopath's and the clinically
insane psychopath's typical endless idiotic blather unread again

....and much better air in here again!

--
about senile Rot Speed:
"This is like having a conversation with someone with brain damage."
MID:

On Sun, 6 Oct 2019 08:18:44 +1100, AlexK, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH 105 !!! lines of the two retarded idiots' endless idiotic blather
unread

....and much better air in here!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID:

On 05/10/2019 22:31, Commander Kinsey wrote:
On Sat, 05 Oct 2019 22:15:34 +0100, AlexK wrote:
"Commander Kinsey" wrote in message
news

Direct drive motors are interesting - I once had a very cheap turntable
that said "direct drive", so I guess it's not always a good thing?

There's a big difference between a turntable motor and
one in a top loading washing machine which needs to
do a variety of different things when washing, adjitating
and spin drying at different speeds.

I know.* Which makes me think it's important for a washing machine.* But
on a turntable, it has to be a very precise speed or the music sounds
****.* It's the last place I'd think of putting one.

Actually I think I remembered wrong, the cheap stereo might have said
"belt drive" on the front.* Direct drive could have been the decent one.

My Sony direct drive turntable bought in 1982 is still in working order
- except that the lid doesn't stay up. If it had been belt drive I
expect the belt would have perished by now. (My Marantz cassette deck,
bought in 1987 hasn't fared so well.)

--
Max Demian

On 05/10/2019 19:46, Mark Lloyd wrote:
On 10/4/19 2:51 PM, Commander Kinsey wrote:

[snip]

I have a LED

That irritates me, why don't you write "an LED"?* How do you say
"LED"? I say "Ell Eee Dee", not "Light Emitting Diode".* So it needs
an "an", not an "a".

"an LED" irritates me. I know the word is "light".

It's "a LED" if you pronounce it as an acronym.

--
Max Demian

On Sat, 5 Oct 2019 23:06:26 +0100, Max Dumb, another mentally deficient
inveterate troll-feeding senile idiot, blathered again:


expect the belt would have perished by now. (My Marantz cassette deck,
bought in 1987 hasn't fared so well.)

Nor did your brain, you senile troll-feeding idiot!

On Sat, 05 Oct 2019 18:23:35 +0100, "Commander Kinsey"
wrote:

On Fri, 04 Oct 2019 23:54:39 +0100, Dave W wrote:

On Thu, 3 Oct 2019 06:37:34 -0700 (PDT), whisky-dave
wrote:

On Thursday, 3 October 2019 14:29:30 UTC+1, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because they're inefficient".

That is the technical answer just lioke why does a wire get hot when curremnt passes through it.

And will we ever make them more efficient?

Probably.

If you plot voltage across the LED versus current through it, the
curve is not linear like a resistor. At low voltage it hardly
conducts, but at higher voltage it conducts a lot, and the curve
flattens like a not very good zener diode, limiting the voltage.

It only limits it for a while, then you get smoke.

Voltage times current equals watts i.e. heat plus a little light.
Light has a power but it's miniscule. Complicated physics theory might
explain how the light is produced and why so little of it, but we
lesser mortals wouldn't be able to understand it.

I always thought an incandescent bulb was 1% light, 99% heat.
A fluorescent tube was 5% light, 95% heat.
And an LED was 10% light, 90% heat.

As a ratio those are about right. 100W tungsten = 20W fluorescent = 10W LED.

But I've been told elsewhere that LEDs are 40% efficient.

OK I stand corrected, I think your efficiencies are right. Perhaps
it's "up to 40%" for exotic LED's.
--
Dave W

On Sat, 05 Oct 2019 23:13:25 +0100, Dave W, yet another mentally deficient,
troll-feeding, senile idiot, blathered:


OK I stand corrected,

LOL "Corrected" by a retard? Just HOW senile are all you troll-feeding
assholes on this ng?

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 22:15:34 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 21:17:00 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 23:46:55 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:17:46 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not
"because
they're inefficient". And will we ever make them more
efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF
of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another
is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the
inputs
though -
SPDIF, USB and HDMI.

Is power factor that important? In a domestic building, you are
not
billed for power factor. I might have a capacitive load, but my
neighbour
has an inductive load, so they even out.

Most neighbours don't have much long term inductive load anymore.

I don't see why it would have reduced.

It has anyway.

For what reason

To get better motors, direct drive etc with washing machines for
example.

What has direct drive got to do with power factor?

They arent the old induction motors with the power factor they had.

I thought all motors created the same inductive load,

But not necessarily on the mains, that's what matters
with the more sophisticated motors used in stuff like
washing machines etc now.

and had to be compensated for if you wanted unity PF.

There is no point in the cost of doing that with domestic appliances.

Direct drive motors are interesting - I once had a very cheap turntable
that said "direct drive", so I guess it's not always a good thing?

There's a big difference between a turntable motor and
one in a top loading washing machine which needs to
do a variety of different things when washing, adjitating
and spin drying at different speeds.

I know. Which makes me think it's important for a washing machine. But
on a turntable, it has to be a very precise speed or the music sounds
****. It's the last place I'd think of putting one.

Its done with those to avoid belts and the downsides with those over time.

Actually I think I remembered wrong, the cheap stereo might have said
"belt drive" on the front. Direct drive could have been the decent one.

Very likely.

From Wikipedia: "Usually motors are built to achieve maximum torque at
high rotational speeds, usually 1500 or 3000 rpm."
I thought motors produced more torque when slower - which is why they
burn out when jammed.

Not relevant to what is being discussed, the power factor.

Aren't I allowed to drift the conversation a little?

Nope, the death squad has its orders...

"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 22:18:44 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news
On Sat, 05 Oct 2019 21:22:03 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 23:49:23 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 19:56:29 +0100, AlexK wrote:



"Commander Kinsey" wrote in message
news On Fri, 04 Oct 2019 09:41:25 +0100, PeterC

wrote:

On Thu, 3 Oct 2019 19:29:42 +0100, Robert wrote:

On 03/10/2019 14:29, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not
"because
they're inefficient". And will we ever make them more
efficient?
Besides the inefficiencies in the LED itself which other posters
have
covered, LED lamps have some current regulation or power supply
built-in
which will not be 100% efficient and thus generates heat.

If my meter is correct, all the LEDs that I've measured have a PF
of
approx.
0.5 - not a good start.
One TV has a PF of 0.97 and is barely warm over the PSU; another
is
0.86
and
is luke warm. The real warmth in the 2nd. one is around the
inputs
though -
SPDIF, USB and HDMI.

I just tested one of mine with a meter, and it gave a power factor
of
1.00, at 256V, 9.8W. Yes I know that's an absurdly high voltage,
but
I
live opposite the substation so it's higher than the rest of the
street,
and they won't do anything about it. I consequently run my
computer,
lights, etc off a UPS, which automatically chops 10 or 20V off
when
needed.
It's the cool white, 9W version of this (not necessarily from this
seller,
but they look identical): http://www.ebay.co.uk/itm/262915986742
They contain a pretty decent looking switched mode PSU, unlike
some
other
bulbs I've seen which have a very simple capacitor dropper.
If any health and softy people want to be annoyed, then be aware
that
I
don't earth them. A couple of them made a humming noise when I
did.
If
I
touch the metal casing of an unearthed unit, and rub my finger
along
it,
I
feel a slight vibration. I guess something is jumping across by
induction.

More likely the capacitance effect you get with double insulated
stuff.

Could be. Would that also cause the buzzing when earthed?

That's more likely to be due to a significant earth current when
earthed.
Easy to measure.

0.020mA per foot of lighting (they're 4.5W per foot). I don't call
that
significant and can't see how it would cause an audible vibration.

Yeah, its more likely to be caused by something else.

Maybe its just not got the internal high frequency transformer potted
or mounted properly and you get resonance effect with the frequency
changing a little when its earthed so that you get the resonance effect
at that slightly different frequency.

I can't remember what the frequency I heard was, but it wasn't that
high,
probably something like 1 kHz. Aren't the transformers way higher than
that?

Yes, but the noise frequency is determined by the mechanical
resonant frequency of the mechanical stuff, not the frequency
of the current thru the transformer. In other words it can be
way lower than the frequency of the current. A sub harmonic in fact.

Ah, that makes sense. So I guess I could also fix it by simply sticking a
small weight on the device, like a lump of blutack, which would lower
the resonant frequency of the casing. But is it the casing that's
vibrating?

If that's the problem, even just jamming something like a toothpick
or bit of cardboard etc in the loose bit or even some superglue there.

On Sat, 05 Oct 2019 23:06:26 +0100, Max Demian wrote:

On 05/10/2019 22:31, Commander Kinsey wrote:
On Sat, 05 Oct 2019 22:15:34 +0100, AlexK wrote:
"Commander Kinsey" wrote in message
news

Direct drive motors are interesting - I once had a very cheap turntable
that said "direct drive", so I guess it's not always a good thing?

There's a big difference between a turntable motor and
one in a top loading washing machine which needs to
do a variety of different things when washing, adjitating
and spin drying at different speeds.

I know. Which makes me think it's important for a washing machine. But
on a turntable, it has to be a very precise speed or the music sounds
****. It's the last place I'd think of putting one.

Actually I think I remembered wrong, the cheap stereo might have said
"belt drive" on the front. Direct drive could have been the decent one.

My Sony direct drive turntable bought in 1982 is still in working order
- except that the lid doesn't stay up. If it had been belt drive I
expect the belt would have perished by now. (My Marantz cassette deck,
bought in 1987 hasn't fared so well.)

Easy to get belts of any size online.

On Sat, 05 Oct 2019 23:08:43 +0100, Max Demian wrote:

On 05/10/2019 19:46, Mark Lloyd wrote:
On 10/4/19 2:51 PM, Commander Kinsey wrote:

[snip]

I have a LED

That irritates me, why don't you write "an LED"? How do you say
"LED"? I say "Ell Eee Dee", not "Light Emitting Diode". So it needs
an "an", not an "a".

"an LED" irritates me. I know the word is "light".

It's "a LED" if you pronounce it as an acronym.

What do you mean by "pronounce it as an acronym"? I would have said that means "ell eee dee" as in you're treating it as an acronym rather than a word and spelling it out.

On Sat, 05 Oct 2019 23:13:25 +0100, Dave W wrote:

On Sat, 05 Oct 2019 18:23:35 +0100, "Commander Kinsey"
wrote:

On Fri, 04 Oct 2019 23:54:39 +0100, Dave W wrote:

On Thu, 3 Oct 2019 06:37:34 -0700 (PDT), whisky-dave
wrote:

On Thursday, 3 October 2019 14:29:30 UTC+1, Commander Kinsey wrote:
Why do LEDs generate heat? I want a technical answer not "because they're inefficient".

That is the technical answer just lioke why does a wire get hot when curremnt passes through it.

And will we ever make them more efficient?

Probably.

If you plot voltage across the LED versus current through it, the
curve is not linear like a resistor. At low voltage it hardly
conducts, but at higher voltage it conducts a lot, and the curve
flattens like a not very good zener diode, limiting the voltage.

It only limits it for a while, then you get smoke.

Voltage times current equals watts i.e. heat plus a little light.
Light has a power but it's miniscule. Complicated physics theory might
explain how the light is produced and why so little of it, but we
lesser mortals wouldn't be able to understand it.

I always thought an incandescent bulb was 1% light, 99% heat.
A fluorescent tube was 5% light, 95% heat.
And an LED was 10% light, 90% heat.

As a ratio those are about right. 100W tungsten = 20W fluorescent = 10W LED.

But I've been told elsewhere that LEDs are 40% efficient.

OK I stand corrected, I think your efficiencies are right. Perhaps
it's "up to 40%" for exotic LED's.

Exotic? Surely the room lighting ones are the most efficient, as that's what they're designed to do?

On Sun, 6 Oct 2019 10:05:40 +1100, AlexK, better known as cantankerous
trolling senile geezer Rodent Speed, wrote:

FLUSH another 119 !!! lines of the two clinically insane cretins' endless
bull****

....and much better air in here again!

--
Sqwertz to Rot Speed:
"This is just a hunch, but I'm betting you're kinda an argumentative
asshole.
MID: