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

"is it dimmable" refers to the use of a phase-cut TRIAC dimmer in combination
with a retrofit LED bulb designed to run on mains power.

This combination does not work for all LED bulbs, because the electronics
in the bulb are trying to put a constant current through the LED independent
on the mains voltage, and now you are cutting down the mains power.
(not even the voltage, really)

You probably have a 13.8V stabilized DC supply in your shack.
Can you use it as a variable-voltage supply by putting a dimmer in
front of it?

No, not really. When you turn down the dimmer, the supply will first
try all it can do to keep the voltage at 13.8, and at some point it can
not achieve that anymore and the voltage will drop, but it will not
be stabilized anymore.

Similarly, a LED bulb may keep constant light emission for a large part
of the dimmer setpoint range, and at some point it goes down in intensity
in an erratic way.


We are just in the first phase of LED lighting deployment, the
"compatability" phase where the bulbs are still using existing form
factors of incandescent bulbs, and are supplied with mains voltage
that is converted to current inside the bulb. It is not the best
solution to use such bulbs in combination with existing dimmers.

Of course a next phase will be to use more reasonable form factors and
connection, where the electronics have a light level setpoint that
determines the LED current and the mains voltage is directly applied
without intermediate phase-cut dimmer.

"Rob" wrote in message
...

This combination does not work for all LED bulbs, because the electronics
in the bulb are trying to put a constant current through the LED
independent
on the mains voltage

Aah! I had not considered the possibility of further integration within the
semiconductor
of the LED.

"gareth" wrote in message
...
"Rob" wrote in message
...

This combination does not work for all LED bulbs, because the electronics
in the bulb are trying to put a constant current through the LED
independent
on the mains voltage

Aah! I had not considered the possibility of further integration within
the semiconductor
of the LED.

Clearly I'm behind the times, for all my LEDs are just that.

In 1972 in my final year at Uni (electronics) I was drawing £3 per week for
all living expenses, and £3 was the cost of an LED, and one of my
contemporaries had special dispensation to include an LED in
his 3rd year project!

(STUDENT grant was £365, £1 per day, and tuition fees
were paid)

On 11/29/2014 4:30 AM, Rob wrote:
Jerry Stuckle wrote:
For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

"is it dimmable" refers to the use of a phase-cut TRIAC dimmer in combination
with a retrofit LED bulb designed to run on mains power.


No, some bulbs are not dimmable, period. Some are. None work reliably
with triac dimmer controls.

This combination does not work for all LED bulbs, because the electronics
in the bulb are trying to put a constant current through the LED independent
on the mains voltage, and now you are cutting down the mains power.
(not even the voltage, really)


True - but non-dimmable bulbs do not work with other dimmers for the
same reason.

You probably have a 13.8V stabilized DC supply in your shack.
Can you use it as a variable-voltage supply by putting a dimmer in
front of it?


Completely unrelated. The LED electronics and the power supply work
completely differently.

No, not really. When you turn down the dimmer, the supply will first
try all it can do to keep the voltage at 13.8, and at some point it can
not achieve that anymore and the voltage will drop, but it will not
be stabilized anymore.

Similarly, a LED bulb may keep constant light emission for a large part
of the dimmer setpoint range, and at some point it goes down in intensity
in an erratic way.


Pretty much, yes. But that is true for any non-dimmable bulb with any
dimmer.


We are just in the first phase of LED lighting deployment, the
"compatability" phase where the bulbs are still using existing form
factors of incandescent bulbs, and are supplied with mains voltage
that is converted to current inside the bulb. It is not the best
solution to use such bulbs in combination with existing dimmers.

Of course a next phase will be to use more reasonable form factors and
connection, where the electronics have a light level setpoint that
determines the LED current and the mains voltage is directly applied
without intermediate phase-cut dimmer.


There are already dimmers made for LEDs which work well. And there are
commercial systems which use low voltage to drive the LEDs. But these
are all proprietary; there are no standards for LED lighting yet.
Eventually, maybe standards will be developed for the commercial market,
but right now there is zero push for such standards.

It's going to be years (if ever) before such standards are created for
the residential market. There are too many reasons to stick with 117V
wiring.

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

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

Jerry Stuckle wrote:
On 11/29/2014 4:30 AM, Rob wrote:
Jerry Stuckle wrote:
For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

"is it dimmable" refers to the use of a phase-cut TRIAC dimmer in combination
with a retrofit LED bulb designed to run on mains power.


No, some bulbs are not dimmable, period. Some are. None work reliably
with triac dimmer controls.

Maybe not in your world, but here we can buy TRIAC dimmers and LED bulbs
that work together.

You probably have a 13.8V stabilized DC supply in your shack.
Can you use it as a variable-voltage supply by putting a dimmer in
front of it?


Completely unrelated. The LED electronics and the power supply work
completely differently.

Maybe your power supply, but mine is a switchmode supply and it works
completely the same as any other. It is regulated for voltage, not for
current, but that is another matter.


There are already dimmers made for LEDs which work well. And there are
commercial systems which use low voltage to drive the LEDs. But these
are all proprietary; there are no standards for LED lighting yet.
Eventually, maybe standards will be developed for the commercial market,
but right now there is zero push for such standards.

It's going to be years (if ever) before such standards are created for
the residential market. There are too many reasons to stick with 117V
wiring.

LED is about current, not about voltage. A lighting system can put many
LEDs in series and use a higher voltage. What is important is that the
supply circuit gets separated from the bulb, so that it can be made dimmable,
externally controlled, etc and the LED gets DC current supply.

The mains here is 230V AC. There even are proposals to change that
into 325V DC or even 500V DC. Not accepted proposals with a set date,
but still. DC supply is more efficient for the home these days, now
everthing uses switchmode supplies, it can transport more power
with the same amount of copper and the same class of insulation.

On 11/29/2014 10:12 AM, Rob wrote:
Jerry Stuckle wrote:
On 11/29/2014 4:30 AM, Rob wrote:
Jerry Stuckle wrote:
For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

"is it dimmable" refers to the use of a phase-cut TRIAC dimmer in combination
with a retrofit LED bulb designed to run on mains power.


No, some bulbs are not dimmable, period. Some are. None work reliably
with triac dimmer controls.

Maybe not in your world, but here we can buy TRIAC dimmers and LED bulbs
that work together.


Maybe you THINK they work. But there are a number of problems (some of
which I have identified in this thread) which show they don't work well
together.

You probably have a 13.8V stabilized DC supply in your shack.
Can you use it as a variable-voltage supply by putting a dimmer in
front of it?


Completely unrelated. The LED electronics and the power supply work
completely differently.

Maybe your power supply, but mine is a switchmode supply and it works
completely the same as any other. It is regulated for voltage, not for
current, but that is another matter.


Completely unrelated. The LED electronics and the power supply work
completely differently.

The first difference you are ignoring is your power supply is constant
voltage. A LED power supply is constant current. They work on entirely
different principles.


There are already dimmers made for LEDs which work well. And there are
commercial systems which use low voltage to drive the LEDs. But these
are all proprietary; there are no standards for LED lighting yet.
Eventually, maybe standards will be developed for the commercial market,
but right now there is zero push for such standards.

It's going to be years (if ever) before such standards are created for
the residential market. There are too many reasons to stick with 117V
wiring.

LED is about current, not about voltage. A lighting system can put many
LEDs in series and use a higher voltage. What is important is that the
supply circuit gets separated from the bulb, so that it can be made dimmable,
externally controlled, etc and the LED gets DC current supply.


Sure they can be connected in series. But that has it's own problems;
you can only go so far. And yes, the LED gets a DC supply - but it's
the generation of the constant current source which causes the problems.

Don't believe me, though. Look at some of the references I have posted
- all written by EEs intimately familiar with the technology.

The mains here is 230V AC. There even are proposals to change that
into 325V DC or even 500V DC. Not accepted proposals with a set date,
but still. DC supply is more efficient for the home these days, now
everthing uses switchmode supplies, it can transport more power
with the same amount of copper and the same class of insulation.


That's fine for you. Personally, I don't expect it to get very far.
But it's not going to happen here.

Back in the 1800's, there was a current war. Nikola Tesla (supported by
George Westinghouse) proposed using AC. Thomas Edison proposed using
DC. Both had their advantages and disadvantages. AC won, obviously.
And now, it is so ingrained into our economy there is no chance of changing.

Although the utilities are building some long distance DC transmission
lines.

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

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

Jerry Stuckle wrote:
Completely unrelated. The LED electronics and the power supply work
completely differently.

Maybe your power supply, but mine is a switchmode supply and it works
completely the same as any other. It is regulated for voltage, not for
current, but that is another matter.


Completely unrelated. The LED electronics and the power supply work
completely differently.

The first difference you are ignoring is your power supply is constant
voltage. A LED power supply is constant current. They work on entirely
different principles.

Constant voltage and constant current are not different principles.
Linear and switchmode are.

Sure they can be connected in series. But that has it's own problems;
you can only go so far. And yes, the LED gets a DC supply - but it's
the generation of the constant current source which causes the problems.

What problems?

Don't believe me, though. Look at some of the references I have posted
- all written by EEs intimately familiar with the technology.

When someone points you at a manufacturer that gets things right you
question the truth...

The mains here is 230V AC. There even are proposals to change that
into 325V DC or even 500V DC. Not accepted proposals with a set date,
but still. DC supply is more efficient for the home these days, now
everthing uses switchmode supplies, it can transport more power
with the same amount of copper and the same class of insulation.


That's fine for you. Personally, I don't expect it to get very far.
But it's not going to happen here.

Of course not. You are living in the USA. There is no innovation
in the USA. I would never expect something to be changed.

Back in the 1800's, there was a current war. Nikola Tesla (supported by
George Westinghouse) proposed using AC. Thomas Edison proposed using
DC. Both had their advantages and disadvantages. AC won, obviously.

At that time, AC had more advantages. Now, DC has.

And now, it is so ingrained into our economy there is no chance of changing.

The economy here works a bit differently. When new systems have
advantages, they get deployed. Especially when they consume less energy.
You know, we have (only) digital TV here. For nearly 10 years no.
Something that will take years in the USA.

Although the utilities are building some long distance DC transmission
lines.

There you are!
A DC transmission line between here and Norway has been operating for
several years. Windenergy parks at sea are also feeding DC.
But at home it is even more of an advantage. E.g. to charge your
electrical car you want as much power as possible, and at DC the same
copper wire with the same insulation and safety concerns can transport
2-4 times more power.

On 11/29/2014 10:41 AM, Rob wrote:
Jerry Stuckle wrote:
Completely unrelated. The LED electronics and the power supply work
completely differently.

Maybe your power supply, but mine is a switchmode supply and it works
completely the same as any other. It is regulated for voltage, not for
current, but that is another matter.


Completely unrelated. The LED electronics and the power supply work
completely differently.

The first difference you are ignoring is your power supply is constant
voltage. A LED power supply is constant current. They work on entirely
different principles.

Constant voltage and constant current are not different principles.
Linear and switchmode are.


No, they operate on entirely different principles.

Sure they can be connected in series. But that has it's own problems;
you can only go so far. And yes, the LED gets a DC supply - but it's
the generation of the constant current source which causes the problems.

What problems?


Please read back through my posts here. I'm not going to repeat myself.

Don't believe me, though. Look at some of the references I have posted
- all written by EEs intimately familiar with the technology.

When someone points you at a manufacturer that gets things right you
question the truth...


What did they get right? Physics doesn't change based on the manufacturer.

If you must know, Phillips is not considered one of the top brands in
the U.S.

The mains here is 230V AC. There even are proposals to change that
into 325V DC or even 500V DC. Not accepted proposals with a set date,
but still. DC supply is more efficient for the home these days, now
everthing uses switchmode supplies, it can transport more power
with the same amount of copper and the same class of insulation.


That's fine for you. Personally, I don't expect it to get very far.
But it's not going to happen here.

Of course not. You are living in the USA. There is no innovation
in the USA. I would never expect something to be changed.


Oh no? ROFLMAO! Who do you think first developed LED bulbs? Here's a
hint: it wasn't Phillips.

Back in the 1800's, there was a current war. Nikola Tesla (supported by
George Westinghouse) proposed using AC. Thomas Edison proposed using
DC. Both had their advantages and disadvantages. AC won, obviously.

At that time, AC had more advantages. Now, DC has.


No, at the time neither had an advantage. You need to read up on the
"war" between Tesla and Edison.

And now, it is so ingrained into our economy there is no chance of changing.

The economy here works a bit differently. When new systems have
advantages, they get deployed. Especially when they consume less energy.
You know, we have (only) digital TV here. For nearly 10 years no.
Something that will take years in the USA.


We have only digital TV here, also. Been that way for over 5 years.

Although the utilities are building some long distance DC transmission
lines.

There you are!
A DC transmission line between here and Norway has been operating for
several years. Windenergy parks at sea are also feeding DC.
But at home it is even more of an advantage. E.g. to charge your
electrical car you want as much power as possible, and at DC the same
copper wire with the same insulation and safety concerns can transport
2-4 times more power.


We've had them for years, also. I don't know when they started, but
utilities are still building them. Probably have been for 20-30 years,
as semiconductors able to handle the power and voltage became available.

We also have a lot of wind turbines - both at see and on land.


--
==================
Remove the "x" from my email address
Jerry Stuckle

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

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

snip

If you must know, Phillips is not considered one of the top brands in
the U.S.

Yeah, they must be trolls.

snip

Oh no? ROFLMAO! Who do you think first developed LED bulbs? Here's a
hint: it wasn't Phillips.

Hint:

The Energy Independence and Security Act (EISA) of 2007 authorized the
Department of Energy (DOE) to establish the Bright Tomorrow Lighting
Prize competition, known as the "L Prize".

On 3 August 2011, DOE awarded the prize in the 60 W replacement category
to a Philips' LED lamp after 18 months of extensive testing.

snip

No, at the time neither had an advantage. You need to read up on the
"war" between Tesla and Edison.

At the time there was no such thing as an effient DC-DC converter but
transformers did exist; that was a HUGE advantage.

snip

We have only digital TV here, also. Been that way for over 5 years.

Nope, we still have legacy analog in many places and that was the
reason the FCC denied the petition to establish a 4M amateur band
in the US.


--
Jim Pennino

In rec.radio.amateur.boatanchors Jerry Stuckle wrote:
On 11/29/2014 4:30 AM, Rob wrote:
Jerry Stuckle wrote:
For incandescent, yes. But not for LED bulbs. If that were the case,
why would some LED bulbs be dimmable and others not?

"is it dimmable" refers to the use of a phase-cut TRIAC dimmer in combination
with a retrofit LED bulb designed to run on mains power.


No, some bulbs are not dimmable, period. Some are. None work reliably
with triac dimmer controls.

According to independant reviews by people NOT selling light bulbs, some
manufacturers bulbs do.

The ones you are selling do not.

snip

It's going to be years (if ever) before such standards are created for
the residential market. There are too many reasons to stick with 117V
wiring.

The standards are being actively developed and have nothing to do with
altering the wiring voltage and everything to do with dimmer and bulb
technology.



--
Jim Pennino