audio recording on IC -help wanted

"Lostgallifreyan" <no-one@nowhere.net> wrote in message
news:Xns995CDAF1D7F48zoodlewurdle@140.99.99.130...
Ron Capik <r.capik@worldnet.att.net> wrote in
news:4682BF3B.8C0201B9@worldnet.att.net:

"Vacuum filled," oh how I enjoy that one. It evokes the image of
someone pouring stuff form this bottle of "vacuum" into each
light bulb.


Hell yes, and as we know that nature (allegedly) abhors a vaccuum, that
someone will really have to press the stuff in there hard. >:)
Only if Nature's got in there first.
 
"Lostgallifreyan" <no-one@nowhere.net> wrote in message
news:Xns99667D668E507zoodlewurdle@140.99.99.130...
John Doe <jdoe@usenetlove.invalid> wrote in
news:7GGji.18519$2v1.10215@newssvr14.news.prodigy.net:

Don't believe everything you read.

Experience is the best teacher.

In other words, LEDs suck for bright light sources.

However, the hype is good for selling them to fools over the
TV/Internet. Like that one guy selling LED light bulbs on TV (USA). He
doesn't explicitly say that they're bright as a lightbulb, but they
are in a lightbulb package and used in the commercial as if they were
a lightbulb. Some people probably fall for that.


In your infinite wisdom, how do you explain this?

http://www.cree.com/products/xlamp.asp

NIST confim the brightness, so you don't have to believe the 'hype', you
only have to ask a few basic technical questions: How efficient is it?
Is there enough light to fit purpose at given cost?


"LED luminaires can only be considered high efficacy if the LED can be
tested (according to UL) to be at least 40 lm/W on the line voltage input
side of any power supply or other device.” Otherwise the fixture is not
considered high efficacy."
Source: http://www.icfi.com/Markets/Energy/doc_files/led-lighting.pdf


Light Type: lm/WW CRI Life (hrs)
Incandescent 17 100 3k
Halogen 20 100 10k
Cree XLamp 7090 XR 48 80 >50k
T12 flourescent 60 75-85 20k
Metal halide 70 70 20k
Cree XLamp 7090 XR-E 70 80 >50k
T8 flourescent 74 75-85 20k
High-pressure sodium 91 22 20k
Low-pressure sodium 120 5 18k
Source: http://www.cree.com/products/pdf/XLamp7090XR-Esheet.pdf

Even if you lose nearly half the light you can still claim high efficiency
to UL standards given the 95% efficient power converters made to run LED
lamps. It would be a poor luminaire that lost that much.

As for actual light output, newer LED's put out 176 lumens or more. That's
still a tad short of what's wanted in many cases, but not by much. 7 to 10
emitters would match a standard 100W incandescent (7 for the 240V type, 10
for the 110V type). Given that the cost of the first CFL's was around Ł26
in the UK, maybe Ł40 in todays money, that puts LED's in a good position,
you can get a lot better device for a lot less than that, even now, and
it's improving fast, a lot faster than the time CFL's took to develop, and
there are probably more ways to cut costs without sacrificing safety.

It would take only a fourfold increase in output from a single emitter at
same cost to make them compete with any other light source for domestic
use, and I think we'll only need to wait a few months for that.

My feelings, too.

Arfa
 
Lostgallifreyan wrote:

John Doe <jdoe@usenetlove.invalid> wrote in
news:7GGji.18519$2v1.10215@newssvr14.news.prodigy.net:

Don't believe everything you read.

Experience is the best teacher.

In other words, LEDs suck for bright light sources.

However, the hype is good for selling them to fools over the
TV/Internet. Like that one guy selling LED light bulbs on TV (USA). He
doesn't explicitly say that they're bright as a lightbulb, but they
are in a lightbulb package and used in the commercial as if they were
a lightbulb. Some people probably fall for that.


In your infinite wisdom, how do you explain this?

http://www.cree.com/products/xlamp.asp

NIST confim the brightness, so you don't have to believe the 'hype', you
only have to ask a few basic technical questions: How efficient is it?
Is there enough light to fit purpose at given cost?

"LED luminaires can only be considered high efficacy if the LED can be
tested (according to UL) to be at least 40 lm/W on the line voltage input
side of any power supply or other device.” Otherwise the fixture is not
considered high efficacy."
Source: http://www.icfi.com/Markets/Energy/doc_files/led-lighting.pdf

Light Type: lm/WW CRI Life (hrs)
Incandescent 17 100 3k
Halogen 20 100 10k
Cree XLamp 7090 XR 48 80 >50k
T12 flourescent 60 75-85 20k
Metal halide 70 70 20k
Cree XLamp 7090 XR-E 70 80 >50k
T8 flourescent 74 75-85 20k
High-pressure sodium 91 22 20k
Low-pressure sodium 120 5 18k
Source: http://www.cree.com/products/pdf/XLamp7090XR-Esheet.pdf

Even if you lose nearly half the light you can still claim high efficiency
to UL standards given the 95% efficient power converters made to run LED
lamps. It would be a poor luminaire that lost that much.

As for actual light output, newer LED's put out 176 lumens or more. That's
still a tad short of what's wanted in many cases, but not by much. 7 to 10
emitters would match a standard 100W incandescent (7 for the 240V type, 10
for the 110V type). Given that the cost of the first CFL's was around Ł26
in the UK, maybe Ł40 in todays money, that puts LED's in a good position,
you can get a lot better device for a lot less than that, even now, and
it's improving fast, a lot faster than the time CFL's took to develop, and
there are probably more ways to cut costs without sacrificing safety.

It would take only a fourfold increase in output from a single emitter at
same cost to make them compete with any other light source for domestic
use, and I think we'll only need to wait a few months for that.
I bet you'll find that LED has a 7000K or so colour temp. They're not very nice
for domestic lighting.

Graham
 
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:468FA633.52502BD5@hotmail.com:

I bet you'll find that LED has a 7000K or so colour temp. They're not
very nice for domestic lighting.
True, I'm not wild about it, but so long as it can improve enough to avoid
sharp dips or peaks I don't mind some serious skew toward blue. We can get
used to it as we get used to changes in the colour of ambient daylight,
which is often close to what LED's already make. The sharper detail from
shortwave blues will help decrease fatigue and increase comfort when
reading or doing small-scale work. My only current beef with them is the
lack of nice rendering of reds. Adding some broadband red centred around
650 nm should fix that.
 
Kevin McMurtrie wrote:

http://www.lumileds.com/products/line.cfm?lineId=19

145 Typical lumens from 700mA @ 3.6V, or 58 lumens per watt. The LED is
a surface mount chip 3.1 x 4.6 x 2.1 millimeters in size. A thin strip
of 12 of these chips puts out light comparable to a 100W tungsten lamp
but only uses 30W.
The colour temperature won't be anywhere near comparable.

In any case don't 'white leds' use the same phosphor method of producing light
that CFLs do ?

Graham
 
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:4692308A.A7CD16AF@hotmail.com:

Lostgallifreyan wrote:

As for actual light output, newer LED's put out 176 lumens or more.

Cite please ?

Graham
Table: Flux Characteristics (Tj = 25°C)
Cree XR-E type P4, 80 lumens at 350 mA
Cree XR-E type Q4, 100 lumens at 350 mA
Graph: "Relative Intensity vs. Current Tj = 25°C)"
Line rising through 100% output at 350 mA to >220% at Imax of 1A.
Source: http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

Logical inference is that the P4 can output >176 at 1 amp, and the Q4 can
do >220 lumens at 1 amp.

NIST tested an XR-E Xlamp at 350 mA and found outputs exceeding that
claimed in the data sheet. They did not measure the output at 1A but they
did certify the lumens per watt.
Source:
http://www.cree.com/products/pdf/NIST%20XLamp%20LED%20Document.pdf

They did not test the output at 1A, or at least did not certify it, but
either the LED's die before you manage to push 1A through them, or they can
do what is claimed. Even if there is a fall-off with current, the Q4 type
will definitely exceed 176 lumens at 1A.
 
And there is newer XR-E Q5 Xlamp too. Not sure what its spec is though.
 
Lostgallifreyan <no-one@nowhere.net> wrote in
news:Xns9968B2044C7D5zoodlewurdle@140.99.99.130:

Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:46923053.192AF430@hotmail.com:

To run LEDs efficiently from 240V AC will also require some active
electronics. I see no-one ever factors in the power losses that'll be
associated with that.


95% efficient power conversion from 5 to 32V and I think I saw similar
claims for a small module that can power a series chain of LED's from
a mains input. Can't cite a source right now, I just got you one
already for the 176 lumens claim. If I can find the other I'll cite
it.
Here's one at 82%: http://www.magtechind.com/__LED_Lighting_PSU/Anz107.pdf
I saw better, but this was one I found while looking for a specific item.
If I find something significantly better on 240 VAC I'll post again.
 
In article <Xns9968B7B144762zoodlewurdle@140.99.99.130>, Lostgallifreyan <no-one@nowhere.net> wrote:
szekeres@pitt.edu (GregS) wrote in
news:f6tf8n$q2t$1@usenet01.srv.cis.pitt.edu:

Just uses a small CPU fan. I'm actually using a CPU sink/fan combo,
but the LED's are epoxied to a copper plate. I even have diamond dust
as a buffer/insulator. To close space the LED's I needed the best
thermal transfer. Did I forget to mention the Peltier device.


I can see why diamond dust might help, but why a TEC? The LED's can operate
at temperatures great enough to pour heat through a decent thermal coupling
to a heatsink, no need to pump it through by force, that just makes work
for work's sake unless you are forced to drop the temperature in a confined
space, which is doubtful given the size of heatsink you need to dissipate
LED heat + TEC work heat.
The LED's maximum rating essentially calls for room temperature. Even with room temperature,
the LED die will be much hotter. As the LED heats up, the light output sags.
Normally, the Luxeons are allready mounted on a piece of aluminum, which looks like
a star, or Luxeon Star. With my mounting arrangement, the Luxeon Emitters are back to back,
thus need faster heat transfer. The actual size of the heat transfer piece off the LED die is very
small, and is electrically insulated with epoxy, so the heat transfer could be improved.

greg
 
Lostgallifreyan wrote:

Eeyore wrote

To run LEDs efficiently from 240V AC will also require some active
electronics. I see no-one ever factors in the power losses that'll be
associated with that.

95% efficient power conversion from 5 to 32V
But that's not mains. Nor do LEDs run off a voltage source. You need to control
the current.


and I think I saw similar claims for a small module that can power a series
chain of LED's from a
mains input.
I very much doubt it. One very important point however is that these need to be
driven with a constant *current* not a constant voltage and that's typically a
lossier method too.

Graham
 
szekeres@pitt.edu (GregS) wrote in
news:f6ttm2$2f$1@usenet01.srv.cis.pitt.edu:

In article <Xns9968B7B144762zoodlewurdle@140.99.99.130>,
Lostgallifreyan <no-one@nowhere.net> wrote:
szekeres@pitt.edu (GregS) wrote in
news:f6tf8n$q2t$1@usenet01.srv.cis.pitt.edu:

Just uses a small CPU fan. I'm actually using a CPU sink/fan combo,
but the LED's are epoxied to a copper plate. I even have diamond
dust as a buffer/insulator. To close space the LED's I needed the
best thermal transfer. Did I forget to mention the Peltier device.


I can see why diamond dust might help, but why a TEC? The LED's can
operate at temperatures great enough to pour heat through a decent
thermal coupling to a heatsink, no need to pump it through by force,
that just makes work for work's sake unless you are forced to drop the
temperature in a confined space, which is doubtful given the size of
heatsink you need to dissipate LED heat + TEC work heat.

The LED's maximum rating essentially calls for room temperature. Even
with room temperature, the LED die will be much hotter. As the LED
heats up, the light output sags. Normally, the Luxeons are allready
mounted on a piece of aluminum, which looks like a star, or Luxeon
Star. With my mounting arrangement, the Luxeon Emitters are back to
back, thus need faster heat transfer. The actual size of the heat
transfer piece off the LED die is very small, and is electrically
insulated with epoxy, so the heat transfer could be improved.

greg
Good point re output drop with heat. It's not so bad though, linear drop to
90% at 70°C. I guess if you have enough of them densely packed it becomes a
specialised lamp, but I imagine a 486 heatsink with no fan should take care
of up to four XR-E's and still operate well below 70°C. K2's are less
efficient. Were anyway, I think newer ones that match Cree's efficiencies
are being made, according to some posts I read on Photonlexicon.

Even at >120°C the chips put out 70% of 25°C rated output, and I doubt even
ten closely packed emitters will get that hot if convection can keep the
mounts below 85°C. Ten emitters in a lightbulb's space couldn't even get
that hot unless they had less than twice the efficiency of 100W tungsten
lamps, and they're a lot more efficient than that, >80 l/W with a claimed
industry best thermal resistance of 8°/W.

Any tips for mounting? :) I'll look deeper at the Cree site for guidance,
but for now I'm contemplating an anodised heatsink (such as used for 486
CPU) and using a thin smear of epoxy to fix three of them in place along
with a small variable-output driver.. That's crude, so I'm keen to hear
some better ideas for improvised assemblies.
 
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:469284D6.7FE92618@hotmail.com:

Lostgallifreyan wrote:

Eeyore wrote

To run LEDs efficiently from 240V AC will also require some active
electronics. I see no-one ever factors in the power losses that'll
be associated with that.

95% efficient power conversion from 5 to 32V

But that's not mains. Nor do LEDs run off a voltage source. You need
to control the current.
Of course it's not mains, I just cited the one example I had, I mentioned
mains later. Might be better to read the whole post before answering, it
wasn't a big one.

As for current not voltage, that is why I said POWER conversion. That's
what LED drivers do, they put out a controlled CURRENT. It is correct to
call this power conversion.

and I think I saw similar claims for a small module that can power a
series chain of LED's from a
mains input.

I very much doubt it. One very important point however is that these
need to be driven with a constant *current* not a constant voltage and
that's typically a lossier method too.
Well, I found one and posted about it already in a later post. 82%, Not too
shabby. That runs directly off 240VAC.

Now, how efficiently can you convert VOLTAGES?? What's the best efficiency
to get say, 240VAC to 30VDC? Take it, whatever it is, then deduct the 5%
from the DC power converter I mentioned above. I suspect it can be better
than 82% total? I imagine >90% might be had. You say that the conversion to
current is the inefficient bit, but that's the task I cited as being done
at 95%. That's why I mentioned the DC power converter, because it is
relevant.
 
Lostgallifreyan wrote:

Eeyore wrote
Lostgallifreyan wrote:

As for actual light output, newer LED's put out 176 lumens or more.

Cite please ?



Table: Flux Characteristics (Tj = 25°C)
Cree XR-E type P4, 80 lumens at 350 mA
Cree XR-E type Q4, 100 lumens at 350 mA
Graph: "Relative Intensity vs. Current Tj = 25°C)"
Line rising through 100% output at 350 mA to >220% at Imax of 1A.
Source: http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

Logical inference is that the P4 can output >176 at 1 amp, and the Q4 can
do >220 lumens at 1 amp.
OK. That's 3.7W of input power. Giving 47.5 and 59.5 lumens/W respecitively for
those 2 leds.


NIST tested an XR-E Xlamp at 350 mA and found outputs exceeding that
claimed in the data sheet. They did not measure the output at 1A but they
did certify the lumens per watt.
Source:
http://www.cree.com/products/pdf/NIST%20XLamp%20LED%20Document.pdf
About 84 lumens @ 350 mA and 75 lumens/W at this lower current.


They did not test the output at 1A, or at least did not certify it, but
either the LED's die before you manage to push 1A through them, or they can
do what is claimed. Even if there is a fall-off with current, the Q4 type
will definitely exceed 176 lumens at 1A.
185 lumens using your figure of 2.2x times the reference brightness @ 1A.

Graham
 
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:46928BDD.F665CB99@hotmail.com:

OK. That's 3.7W of input power. Giving 47.5 and 59.5 lumens/W
respecitively for those 2 leds.
Tell that to NIST >:)
 
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:46928BDD.F665CB99@hotmail.com:

185 lumens using your figure of 2.2x times the reference brightness @
1A.
That should satisfy you then. You challenged me to cite proof of 176 mW as
if I was claiming too much. Are you now saying I'm wrong because it's not
EXACTLY 176 mW? If so I'm done discussing the matter.
 
Lostgallifreyan wrote:

Lostgallifreyan wrote
Eeyore wrote

To run LEDs efficiently from 240V AC will also require some active
electronics. I see no-one ever factors in the power losses that'll be
associated with that.


95% efficient power conversion from 5 to 32V and I think I saw similar
claims for a small module that can power a series chain of LED's from
a mains input. Can't cite a source right now, I just got you one
already for the 176 lumens claim. If I can find the other I'll cite
it.

Here's one at 82%: http://www.magtechind.com/__LED_Lighting_PSU/Anz107.pdf
I saw better, but this was one I found while looking for a specific item.
If I find something significantly better on 240 VAC I'll post again.
I doubt you'll do much better actually. 82% sounds about right (not 95%) however
that is at max load.

I see they don't state efficiency for the lower power models.

Graham
 
Lostgallifreyan wrote:

Even at >120°C the chips put out 70% of 25°C rated output, and I doubt even
ten closely packed emitters will get that hot if convection can keep the
mounts below 85°C. Ten emitters in a lightbulb's space couldn't even get
that hot unless they had less than twice the efficiency of 100W tungsten
lamps.
How do you work that out ?

Ten emitters of the current best type account for about 34W ! You'll have a
hell of a job keeping them below 70C or so in the space of a current lighbulb !
Forced cooling would be essential and that's going to be annoying. How many fans
last 50,000 hrs too ? I'm sure they'd get end up overheating through dust
build-up reducing fan efficiency too.

Graham
 
Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:4692903D.8CC2A947@hotmail.com:

Lostgallifreyan wrote:

Even at >120°C the chips put out 70% of 25°C rated output, and I
doubt even ten closely packed emitters will get that hot if
convection can keep the mounts below 85°C. Ten emitters in a
lightbulb's space couldn't even get that hot unless they had less
than twice the efficiency of 100W tungsten lamps.

How do you work that out ?

Ten emitters of the current best type account for about 34W ! You'll
have a hell of a job keeping them below 70C or so in the space of a
current lighbulb ! Forced cooling would be essential and that's going
to be annoying. How many fans last 50,000 hrs too ? I'm sure they'd
get end up overheating through dust build-up reducing fan efficiency
too.
Ok, I think it will run hotter than I was suggesting, but you're forgetting
something too, a much greater chunk of that imput wattage will be emitted
as light, not heat, compared with tungsten lamps.
 
Lostgallifreyan wrote:

Eeyore wrote
Lostgallifreyan wrote:
Eeyore wrote

To run LEDs efficiently from 240V AC will also require some active
electronics. I see no-one ever factors in the power losses that'll
be associated with that.

95% efficient power conversion from 5 to 32V

But that's not mains. Nor do LEDs run off a voltage source. You need
to control the current.


Of course it's not mains, I just cited the one example I had, I mentioned
mains later. Might be better to read the whole post before answering, it
wasn't a big one.

As for current not voltage, that is why I said POWER conversion. That's
what LED drivers do, they put out a controlled CURRENT. It is correct to
call this power conversion.
However you did mention volts previously. It wasn't me who did that.


and I think I saw similar claims for a small module that can power a
series chain of LED's from a
mains input.

I very much doubt it. One very important point however is that these
need to be driven with a constant *current* not a constant voltage and
that's typically a lossier method too.


Well, I found one and posted about it already in a later post. 82%, Not too
shabby. That runs directly off 240VAC.

Now, how efficiently can you convert VOLTAGES?? What's the best efficiency
to get say, 240VAC to 30VDC? Take it, whatever it is, then deduct the 5%
from the DC power converter I mentioned above. I suspect it can be better
than 82% total? I imagine >90% might be had. You say that the conversion to
current is the inefficient bit, but that's the task I cited as being done
at 95%. That's why I mentioned the DC power converter, because it is
relevant.
LEDS operate at lowish voltages. You tend to get lower efficiencies with at
lowish voltages, largely due to rectifier losses.

I doubt you'll much better 85% power conversion efficiency overall from the AC
line to the LED package actually. That would be a *very* good figure.

Graham
 

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