On 11/28/2014 7:05 PM, rickman wrote:
On 11/28/2014 6:16 PM, Jerry Stuckle wrote:
On 11/28/2014 5:24 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle
wrote:
On 11/28/2014 4:11 PM, wrote:
In rec.radio.amateur.boatanchors Michael Black wrote:
On Fri, 28 Nov 2014, wrote:

In rec.radio.amateur.boatanchors gareth
wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

As the regulators are potted in and would be difficult to remove,
and
since LED's run on voltages on the order of 2-3 volts, no.

How many 3 volt valves can you name?

I think that point was that if a regulator was used to drop the line
voltage to those 3volts, it could handle high voltage input. The
probably
false assumption is that the regulator would be variable from some
very
high output voltage to some very low output voltage, so one could
use it
for tubes by making that adjustment.

Given that manufacturers want the least cost in a product, and the
regulator in a light bulb would have no need for a variable regulator,
and that these things are made in the millions, it would be extremely
silly to assume that the regulator is anything other than a fixed
regulator for LED's and is designed to handle the load of some fixed
number of LED's.


Once again, incorrect. Have you ever heard of "dimmable LED bulbs"?
How do you dim without an adjustable regulator?

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?


For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

To specifically answer your question, you design a regulator who's
output
is some precentage of the raw input as opposed to a regulator who's
output is always equal to some reference voltage.


Again, it all depends.

And to be yet more specific, since LED brightness is proportional to
current and resistors would waste power, the regulator would be a
current regulator with an average current output proportional to the
raw input voltage.


Then why can't you use standard incandescent dimmers with LED bulbs?

A lot of IC regulators can't handle high voltage. If nothing
else, nobody
saw the need, it was the solid state age. So dissipation issues
aside,
most regulators expect at most a relatively low DC voltage input.

True for IC regulators. Hoever high voltage transistors exist these
days which makes designing a high voltage regulator pretty trivial.


Sure. But how do you handle the current requirements without some kind
of transformer?

Well, assuming you want some voltage greater than the wall plug maximum,
the need for a transformer is pretty much a given unless some sort of
voltage multiplying rectifier is sufficient for the need, which is
where the current requirement becomes relevant.

However, the subject was high voltage regulators, not where does the
raw high voltage come from.


And where do you get the current necessary to supply the LEDs in the
bulbs? A typical LED required around 3V (usually 2.7V to 3.3V,
depending on the LED)? A 9 watt LED would require 3 amps of current.
Or, if the LEDs were in series, something less. But without a
transformer, the current would still exceed that of an incandescent bulb.

You obviously are unfamiliar with the structure of LED bulbs.

You two are both speculating and have limited information to base either
of your opinions on. Jim says,

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?

which is not correct in that most dimmers work by reducing the phase
angle of the applied AC or to reduce noise some simply don't turn on for
entire half cycles.

Jerry says,

Then why can't you use standard incandescent dimmers with LED bulbs?

Which is wrong because you can use "standard" dimmers, but the LED bulb
has to be designed for it.

Try reading a little...

http://www.ledsmagazine.com/articles...-magazine.html



Rickman, here's a better page from the manufacturer of dimmers (and one
of the lines we carry):

http://www.lutron.com/en-US/Educatio...LsandLEDs.aspx

Note the paragraph under "Do all LED and CFL light bulbs work with all
dimmers?"

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

On 11/28/2014 8:31 PM, wrote:
In rec.radio.amateur.boatanchors rickman wrote:
On 11/28/2014 7:37 PM, wrote:

snip

See:

http://en.wikipedia.org/wiki/Thyristor#Applications

Please be as pedantic as you like. You are wrong.

No, I am not, and I am being precise in my language.

The very article you reference shows that the dimmer works by
controlling the phase angle over which the AC voltage is passed to the
load.

Which is the phase angle, or more properly, the conduction angle of the
contolling device, not the phase angle of the AC source.

If the voltage is turned off for part of the conduction cycle, the
average voltage changes.

This is Electronics 101.

There are *many* LED bulbs which can be dimmed by this standard
type of dimmer.

Yes, there are, but that is irrelevant to how a dimmer works and only
relevant to how the bulb works.

As the reference I provide shows,

What reference?

these bulbs include
smarts to measure this phase angle

You mean conduction angle?

You can't measure a phase angle absent a reference signal of a known
phase.

Again, Electronic 101.

and adjust the bulb brightness
accordingly. I have several in my home.

Whoopee!!

Ok, if you really want to discuss this let me know.

--

Rick

On 11/28/2014 8:52 PM, Jerry Stuckle wrote:
On 11/28/2014 7:05 PM, rickman wrote:
On 11/28/2014 6:16 PM, Jerry Stuckle wrote:
On 11/28/2014 5:24 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle
wrote:
On 11/28/2014 4:11 PM, wrote:
In rec.radio.amateur.boatanchors Michael Black wrote:
On Fri, 28 Nov 2014, wrote:

In rec.radio.amateur.boatanchors gareth
wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

As the regulators are potted in and would be difficult to remove,
and
since LED's run on voltages on the order of 2-3 volts, no.

How many 3 volt valves can you name?

I think that point was that if a regulator was used to drop the line
voltage to those 3volts, it could handle high voltage input. The
probably
false assumption is that the regulator would be variable from some
very
high output voltage to some very low output voltage, so one could
use it
for tubes by making that adjustment.

Given that manufacturers want the least cost in a product, and the
regulator in a light bulb would have no need for a variable regulator,
and that these things are made in the millions, it would be extremely
silly to assume that the regulator is anything other than a fixed
regulator for LED's and is designed to handle the load of some fixed
number of LED's.


Once again, incorrect. Have you ever heard of "dimmable LED bulbs"?
How do you dim without an adjustable regulator?

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?


For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

To specifically answer your question, you design a regulator who's
output
is some precentage of the raw input as opposed to a regulator who's
output is always equal to some reference voltage.


Again, it all depends.

And to be yet more specific, since LED brightness is proportional to
current and resistors would waste power, the regulator would be a
current regulator with an average current output proportional to the
raw input voltage.


Then why can't you use standard incandescent dimmers with LED bulbs?

A lot of IC regulators can't handle high voltage. If nothing
else, nobody
saw the need, it was the solid state age. So dissipation issues
aside,
most regulators expect at most a relatively low DC voltage input.

True for IC regulators. Hoever high voltage transistors exist these
days which makes designing a high voltage regulator pretty trivial.


Sure. But how do you handle the current requirements without some kind
of transformer?

Well, assuming you want some voltage greater than the wall plug maximum,
the need for a transformer is pretty much a given unless some sort of
voltage multiplying rectifier is sufficient for the need, which is
where the current requirement becomes relevant.

However, the subject was high voltage regulators, not where does the
raw high voltage come from.


And where do you get the current necessary to supply the LEDs in the
bulbs? A typical LED required around 3V (usually 2.7V to 3.3V,
depending on the LED)? A 9 watt LED would require 3 amps of current.
Or, if the LEDs were in series, something less. But without a
transformer, the current would still exceed that of an incandescent bulb.

You obviously are unfamiliar with the structure of LED bulbs.

You two are both speculating and have limited information to base either
of your opinions on. Jim says,


Sorry, but lighting control has been my job for much of the last 11
years. I am considered an expert in it by many of my peers and teach
courses on it. We also install many different lighting systems,
including LED.

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?

which is not correct in that most dimmers work by reducing the phase
angle of the applied AC or to reduce noise some simply don't turn on for
entire half cycles.

Jerry says,

Then why can't you use standard incandescent dimmers with LED bulbs?

Which is wrong because you can use "standard" dimmers, but the LED bulb
has to be designed for it.


Which they aren't for many reasons that I won't get into here.

Really? So the standard dimmers in my home can't work with the dimmable
LED bulbs they are connected to and seem to control just fine?


Try reading a little...

http://www.ledsmagazine.com/articles...-magazine.html



This article is sorely lacking in facts. Notice the title: "LED
lighting must work with legacy dimming technologies".

There are a number of problems with dimmable LED bulbs and the standard
triac dimmer. See above. And I suggest you read more reliable
information. LED bulb manufacturer's information is a better start.

How do you explain the several LED bulbs I have working on standard
dimmers in my home?

--

Rick

On 11/28/2014 9:34 PM, Jerry Stuckle wrote:
On 11/28/2014 7:05 PM, rickman wrote:
On 11/28/2014 6:16 PM, Jerry Stuckle wrote:
On 11/28/2014 5:24 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle
wrote:
On 11/28/2014 4:11 PM, wrote:
In rec.radio.amateur.boatanchors Michael Black wrote:
On Fri, 28 Nov 2014, wrote:

In rec.radio.amateur.boatanchors gareth
wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

As the regulators are potted in and would be difficult to remove,
and
since LED's run on voltages on the order of 2-3 volts, no.

How many 3 volt valves can you name?

I think that point was that if a regulator was used to drop the line
voltage to those 3volts, it could handle high voltage input. The
probably
false assumption is that the regulator would be variable from some
very
high output voltage to some very low output voltage, so one could
use it
for tubes by making that adjustment.

Given that manufacturers want the least cost in a product, and the
regulator in a light bulb would have no need for a variable regulator,
and that these things are made in the millions, it would be extremely
silly to assume that the regulator is anything other than a fixed
regulator for LED's and is designed to handle the load of some fixed
number of LED's.


Once again, incorrect. Have you ever heard of "dimmable LED bulbs"?
How do you dim without an adjustable regulator?

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?


For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

To specifically answer your question, you design a regulator who's
output
is some precentage of the raw input as opposed to a regulator who's
output is always equal to some reference voltage.


Again, it all depends.

And to be yet more specific, since LED brightness is proportional to
current and resistors would waste power, the regulator would be a
current regulator with an average current output proportional to the
raw input voltage.


Then why can't you use standard incandescent dimmers with LED bulbs?

A lot of IC regulators can't handle high voltage. If nothing
else, nobody
saw the need, it was the solid state age. So dissipation issues
aside,
most regulators expect at most a relatively low DC voltage input.

True for IC regulators. Hoever high voltage transistors exist these
days which makes designing a high voltage regulator pretty trivial.


Sure. But how do you handle the current requirements without some kind
of transformer?

Well, assuming you want some voltage greater than the wall plug maximum,
the need for a transformer is pretty much a given unless some sort of
voltage multiplying rectifier is sufficient for the need, which is
where the current requirement becomes relevant.

However, the subject was high voltage regulators, not where does the
raw high voltage come from.


And where do you get the current necessary to supply the LEDs in the
bulbs? A typical LED required around 3V (usually 2.7V to 3.3V,
depending on the LED)? A 9 watt LED would require 3 amps of current.
Or, if the LEDs were in series, something less. But without a
transformer, the current would still exceed that of an incandescent bulb.

You obviously are unfamiliar with the structure of LED bulbs.

You two are both speculating and have limited information to base either
of your opinions on. Jim says,

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?

which is not correct in that most dimmers work by reducing the phase
angle of the applied AC or to reduce noise some simply don't turn on for
entire half cycles.

Jerry says,

Then why can't you use standard incandescent dimmers with LED bulbs?

Which is wrong because you can use "standard" dimmers, but the LED bulb
has to be designed for it.

Try reading a little...

http://www.ledsmagazine.com/articles...-magazine.html



Rickman, here's a better page from the manufacturer of dimmers (and one
of the lines we carry):

http://www.lutron.com/en-US/Educatio...LsandLEDs.aspx

Note the paragraph under "Do all LED and CFL light bulbs work with all
dimmers?"

That has even less information than the page I referred you to.

Your link says nothing about LED lights in general, only the Lutron
devices. As the article I referenced indicated, LEDs can be made to
work with generic phase control dimmers and the several LED bulbs I have
that work prove the point. I especially like Lutron's compatibility
list. They have a wide definition of "compatible"....

"Products on this list are considered compatible with the respective
Lutron C·L dimmers. Depending on the quality of the bulb you select,
compatible bulbs may still:
- have less dimming range than an incandescent or halogen bulb
- dim less smoothly than an incandescent or halogen bulb
- flicker or shimmer at certain light levels
- buzz"

LOL. If the combination does any of these things I don't consider that
to be "compatible".

Actually I find Lutron to have some real crap product as well as very
poor customer support. In order to assure I could get compatible dimmer
and lamp, I bought an LED fixture that listed part numbers for
compatible dimmers (tested in conjunction with the dimmer companies) and
bought a compatible Lutron dimmer. The result was they didn't work
properly. Clearly this particular fixture was *not* compatible with
generic dimmers and wasn't even compatible with the specified dimmer.

I contacted both Lutron and the company who made the fixture. I don't
recall the response of the LED fixture company but Lutron simply
recommended another dimmer with no mention of why they were on the
compatibility list and yet were not compatible.

--

Rick

On 11/28/2014 10:39 PM, rickman wrote:
On 11/28/2014 8:52 PM, Jerry Stuckle wrote:
On 11/28/2014 7:05 PM, rickman wrote:
On 11/28/2014 6:16 PM, Jerry Stuckle wrote:
On 11/28/2014 5:24 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle
wrote:
On 11/28/2014 4:11 PM, wrote:
In rec.radio.amateur.boatanchors Michael Black wrote:
On Fri, 28 Nov 2014, wrote:

In rec.radio.amateur.boatanchors gareth
wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

As the regulators are potted in and would be difficult to remove,
and
since LED's run on voltages on the order of 2-3 volts, no.

How many 3 volt valves can you name?

I think that point was that if a regulator was used to drop the
line
voltage to those 3volts, it could handle high voltage input. The
probably
false assumption is that the regulator would be variable from some
very
high output voltage to some very low output voltage, so one could
use it
for tubes by making that adjustment.

Given that manufacturers want the least cost in a product, and the
regulator in a light bulb would have no need for a variable
regulator,
and that these things are made in the millions, it would be
extremely
silly to assume that the regulator is anything other than a fixed
regulator for LED's and is designed to handle the load of some fixed
number of LED's.


Once again, incorrect. Have you ever heard of "dimmable LED bulbs"?
How do you dim without an adjustable regulator?

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?


For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

To specifically answer your question, you design a regulator who's
output
is some precentage of the raw input as opposed to a regulator who's
output is always equal to some reference voltage.


Again, it all depends.

And to be yet more specific, since LED brightness is proportional to
current and resistors would waste power, the regulator would be a
current regulator with an average current output proportional to the
raw input voltage.


Then why can't you use standard incandescent dimmers with LED bulbs?

A lot of IC regulators can't handle high voltage. If nothing
else, nobody
saw the need, it was the solid state age. So dissipation issues
aside,
most regulators expect at most a relatively low DC voltage input.

True for IC regulators. Hoever high voltage transistors exist these
days which makes designing a high voltage regulator pretty trivial.


Sure. But how do you handle the current requirements without some
kind
of transformer?

Well, assuming you want some voltage greater than the wall plug
maximum,
the need for a transformer is pretty much a given unless some sort of
voltage multiplying rectifier is sufficient for the need, which is
where the current requirement becomes relevant.

However, the subject was high voltage regulators, not where does the
raw high voltage come from.


And where do you get the current necessary to supply the LEDs in the
bulbs? A typical LED required around 3V (usually 2.7V to 3.3V,
depending on the LED)? A 9 watt LED would require 3 amps of current.
Or, if the LEDs were in series, something less. But without a
transformer, the current would still exceed that of an incandescent
bulb.

You obviously are unfamiliar with the structure of LED bulbs.

You two are both speculating and have limited information to base either
of your opinions on. Jim says,


Sorry, but lighting control has been my job for much of the last 11
years. I am considered an expert in it by many of my peers and teach
courses on it. We also install many different lighting systems,
including LED.

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?

which is not correct in that most dimmers work by reducing the phase
angle of the applied AC or to reduce noise some simply don't turn on for
entire half cycles.

Jerry says,

Then why can't you use standard incandescent dimmers with LED bulbs?

Which is wrong because you can use "standard" dimmers, but the LED bulb
has to be designed for it.


Which they aren't for many reasons that I won't get into here.

Really? So the standard dimmers in my home can't work with the dimmable
LED bulbs they are connected to and seem to control just fine?


Try reading a little...

http://www.ledsmagazine.com/articles...-magazine.html




This article is sorely lacking in facts. Notice the title: "LED
lighting must work with legacy dimming technologies".

There are a number of problems with dimmable LED bulbs and the standard
triac dimmer. See above. And I suggest you read more reliable
information. LED bulb manufacturer's information is a better start.

How do you explain the several LED bulbs I have working on standard
dimmers in my home?


Rick,

How do you explain the manufacturer of dimmers says standard dimmers
cannot be used reliably?

But since you want the details, here is a start. There are a number of
problems with standard incandescent dimmers. Since they cut off the
initial phase of the positive and negative phases, when they start
conducting there is a large surge of power. This surge causes
additional heat buildup in a switching power supply and can cause
premature failure of the bulb and/or dimmer.

If you look at travel adapters for running U.S. devices on European
voltages, you'll find two different types - electronic switching and
standard transformer. You will notice the electronic switching supplies
are higher powered have cautions not to use them with electronic loads
such as radios and TV's. This is for the same reason as dimmers on LEDs
- the dimmer does not put out a clean waveform.

Transformer-based travel adapters have no such limitation because they
put out a clean signal, but have lower power ratings.

There are other problems, also. Conventional dimmers having a minimum
load (minimum current flowing through triacs). If the minimum load to
maintain conduction is 10W, a 15W LED will only dim to 2/3 power before
turning off.

Dimmable LED bulbs are also very sensitive to voltage fluctuations, and
can flicker with variations in the line voltage. This is especially
true when operating near that cutoff voltage noted above.

Also, since LED's respond immediately to current changes (unlike
incandescent, which have a high thermal inertia), there is a tendency
for them to flicker when the wrong dimmer is used. Sure, it's 120 hz
flicker - but some people are sensitive to it and can suffer headaches.
Worst case, but fortunately very rare, the flash can cause epileptic
seizures those sensitive to it.

These are some of the most serious problems with using conventional
dimmers with LED bulbs. It's also why manufacturers spend a lot of
money developing special dimmers for LED bulbs.

I would also recommend you check other manufacturer's of LED bulb
dimmers. You will find they all have the same cautions. But since
these pages are intended for consumers, they obviously leave out the
technical details. Those are available to dealers, though, either
through dealer-only pages or dealer support.

--
==================
Remove the "x" from my email address
Jerry, AI0K

==================

In rec.radio.amateur.boatanchors Jerry Stuckle wrote:

snip

Note the paragraph under "Do all LED and CFL light bulbs work with all
dimmers?"

No, thet don't, it depends on the manufacturer of the bulb.

Here's a couple of references from someone that does not sell light bulbs
or dimmers:

http://www.cnet.com/how-to/five-thin...ing-led-bulbs/

http://www.cnet.com/news/which-led-l...t-for-dimming/



--
Jim Pennino

In rec.radio.amateur.boatanchors Jerry Stuckle wrote:
On 11/28/2014 9:10 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle wrote:

snip

No, I am arguing from facts - unlike you. I've been in the business of
installing lighting control (and other things) for 11 years now. We
install numerous LED control systems every year.

I forgot that you are an expert on EVERYTHING and to call into question
anything you say is the ultimate insult.


You've just proven once again that you're an expert in NOTHING.

And you've just proven once again that all that you know is what you have
supposedly done, not what exists in the world.

Here is a couple of articles on the subject from people who do NOT make
a living selling either light bulbs or controls.

http://www.cnet.com/how-to/five-thin...ing-led-bulbs/
http://www.cnet.com/news/which-led-l...t-for-dimming/

It seems that yes, dimmable LED bulbs are available for legacy dimmers,
and they work just fine.

snip

--
Jim Pennino

Jerry Stuckle wrote:
No, these have electronic power supplies in them. Otherwise they would
dissipate huge amounts of heat. Think about it. LED's run at about 3V.
That means a 9W LED requires about 3 amps of power. 3 amps at 240V is
720W - or about 711W of power wasted. They would be way less efficient
than any other type of bulbs. Plus LED's run on DC and would not work
as efficiently on 50Hz AC.

9W is an enormous amount of power for an LED. The LEDs used to replace
pilot lamps are normally running 10mA, not 3 amps. This is what allows
a dropping resistor to be used.
--scott


--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 11/28/2014 11:01 PM, Jerry Stuckle wrote:
On 11/28/2014 10:39 PM, rickman wrote:
On 11/28/2014 8:52 PM, Jerry Stuckle wrote:
On 11/28/2014 7:05 PM, rickman wrote:
On 11/28/2014 6:16 PM, Jerry Stuckle wrote:
On 11/28/2014 5:24 PM, wrote:
In rec.radio.amateur.boatanchors Jerry Stuckle
wrote:
On 11/28/2014 4:11 PM, wrote:
In rec.radio.amateur.boatanchors Michael Black wrote:
On Fri, 28 Nov 2014, wrote:

In rec.radio.amateur.boatanchors gareth
wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

As the regulators are potted in and would be difficult to remove,
and
since LED's run on voltages on the order of 2-3 volts, no.

How many 3 volt valves can you name?

I think that point was that if a regulator was used to drop the
line
voltage to those 3volts, it could handle high voltage input. The
probably
false assumption is that the regulator would be variable from some
very
high output voltage to some very low output voltage, so one could
use it
for tubes by making that adjustment.

Given that manufacturers want the least cost in a product, and the
regulator in a light bulb would have no need for a variable
regulator,
and that these things are made in the millions, it would be
extremely
silly to assume that the regulator is anything other than a fixed
regulator for LED's and is designed to handle the load of some fixed
number of LED's.


Once again, incorrect. Have you ever heard of "dimmable LED bulbs"?
How do you dim without an adjustable regulator?

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?


For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

To specifically answer your question, you design a regulator who's
output
is some precentage of the raw input as opposed to a regulator who's
output is always equal to some reference voltage.


Again, it all depends.

And to be yet more specific, since LED brightness is proportional to
current and resistors would waste power, the regulator would be a
current regulator with an average current output proportional to the
raw input voltage.


Then why can't you use standard incandescent dimmers with LED bulbs?

A lot of IC regulators can't handle high voltage. If nothing
else, nobody
saw the need, it was the solid state age. So dissipation issues
aside,
most regulators expect at most a relatively low DC voltage input.

True for IC regulators. Hoever high voltage transistors exist these
days which makes designing a high voltage regulator pretty trivial.


Sure. But how do you handle the current requirements without some
kind
of transformer?

Well, assuming you want some voltage greater than the wall plug
maximum,
the need for a transformer is pretty much a given unless some sort of
voltage multiplying rectifier is sufficient for the need, which is
where the current requirement becomes relevant.

However, the subject was high voltage regulators, not where does the
raw high voltage come from.


And where do you get the current necessary to supply the LEDs in the
bulbs? A typical LED required around 3V (usually 2.7V to 3.3V,
depending on the LED)? A 9 watt LED would require 3 amps of current.
Or, if the LEDs were in series, something less. But without a
transformer, the current would still exceed that of an incandescent
bulb.

You obviously are unfamiliar with the structure of LED bulbs.

You two are both speculating and have limited information to base either
of your opinions on. Jim says,


Sorry, but lighting control has been my job for much of the last 11
years. I am considered an expert in it by many of my peers and teach
courses on it. We also install many different lighting systems,
including LED.

You do realize that a dimmable light bulb is dimmed by changeing the
supply voltage and not by anything else connected to the bulb?

which is not correct in that most dimmers work by reducing the phase
angle of the applied AC or to reduce noise some simply don't turn on for
entire half cycles.

Jerry says,

Then why can't you use standard incandescent dimmers with LED bulbs?

Which is wrong because you can use "standard" dimmers, but the LED bulb
has to be designed for it.


Which they aren't for many reasons that I won't get into here.

Really? So the standard dimmers in my home can't work with the dimmable
LED bulbs they are connected to and seem to control just fine?


Try reading a little...

http://www.ledsmagazine.com/articles...-magazine.html




This article is sorely lacking in facts. Notice the title: "LED
lighting must work with legacy dimming technologies".

There are a number of problems with dimmable LED bulbs and the standard
triac dimmer. See above. And I suggest you read more reliable
information. LED bulb manufacturer's information is a better start.

How do you explain the several LED bulbs I have working on standard
dimmers in my home?


Rick,

How do you explain the manufacturer of dimmers says standard dimmers
cannot be used reliably?

I don't see where they said that. They are only talking about their own
products.


But since you want the details, here is a start. There are a number of
problems with standard incandescent dimmers. Since they cut off the
initial phase of the positive and negative phases, when they start
conducting there is a large surge of power. This surge causes
additional heat buildup in a switching power supply and can cause
premature failure of the bulb and/or dimmer.

Dealing with this heat would be part of the design requirements for a
"dimmable" LED bulb, no?


If you look at travel adapters for running U.S. devices on European
voltages, you'll find two different types - electronic switching and
standard transformer. You will notice the electronic switching supplies
are higher powered have cautions not to use them with electronic loads
such as radios and TV's. This is for the same reason as dimmers on LEDs
- the dimmer does not put out a clean waveform.

Transformer-based travel adapters have no such limitation because they
put out a clean signal, but have lower power ratings.

There are other problems, also. Conventional dimmers having a minimum
load (minimum current flowing through triacs). If the minimum load to
maintain conduction is 10W, a 15W LED will only dim to 2/3 power before
turning off.

Dimmable LED bulbs are also very sensitive to voltage fluctuations, and
can flicker with variations in the line voltage. This is especially
true when operating near that cutoff voltage noted above.

Again, this is a design issue and one that is present even when not
being dimmed.


Also, since LED's respond immediately to current changes (unlike
incandescent, which have a high thermal inertia), there is a tendency
for them to flicker when the wrong dimmer is used. Sure, it's 120 hz
flicker - but some people are sensitive to it and can suffer headaches.
Worst case, but fortunately very rare, the flash can cause epileptic
seizures those sensitive to it.

I have seen no information that 120 Hz flicker is in any way noticeable
or that anyone is sensitive to it. Monitors have flickered at much
lower rates for a very long time. Plus... again, this is an issue
without dimmers.


These are some of the most serious problems with using conventional
dimmers with LED bulbs. It's also why manufacturers spend a lot of
money developing special dimmers for LED bulbs.

I would also recommend you check other manufacturer's of LED bulb
dimmers. You will find they all have the same cautions. But since
these pages are intended for consumers, they obviously leave out the
technical details. Those are available to dealers, though, either
through dealer-only pages or dealer support.

And yet, I have dimmers that work...

--

Rick

On Friday, November 28, 2014 8:20:14 AM UTC-5, gareth wrote:
These LED replacements for 240V mains lamps; if one were to
open them, would one find a high voltage regulator suitable for
some of our valve experiments and repairs?

There is not a whole lot in there.
AC/DC supply, Buck/Boost controller chip with triac dimmer sensing (if it's a dimmable LED lamp), small inductors caps, rectifiers.

TI and ONSemi have controllers and reference designs at their web sites.
I don't know if the govt regulators are requiring any sort of power factor correction.

There is a whole lot of power factor correction circuitry going into higher current consumer goods in the EU so there should be good parts(inductors rectifiers, switches, caps) in a few years when consumers begin yearning for newer models.