Unquestionably Confused writes:
On 11/12/2016 5:52 PM, Gramps' shop wrote:
Thanks. Fluorescents are cheaper, but I have decided on the Costco leds.



So, Larry, what's the verdict? Have you purchased and installed those
Costo lights yet?

I've got both the CostCo LED F40T12 replacements and the dedicated
costco 48" LED fixture. They both work well so far (the T12 replacements
are in a former fluorescent fixture in the attic, and the dedicated
fixture is over the workbench in the shop (augmenting 4x2xF96T12 C50's).

The color temp for the dedicated fixture isn't 5000k, but it's not
too far off.

On 11/17/2016 8:14 AM, Swingman wrote:
On 11/16/2016 10:00 PM, Martin Eastburn wrote:
Yes I've been this way since "Line charges" were in effect. Charge for
the number of lines of text that came through the dial up news server or
email server. Before the WWW came along...

And, as we used to point out to those using that as an excuse, before
the "www came along ...":

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?



Tahw?

On Thursday, November 17, 2016 at 11:41:16 AM UTC-5, Leon wrote:
On 11/17/2016 8:14 AM, Swingman wrote:
On 11/16/2016 10:00 PM, Martin Eastburn wrote:
Yes I've been this way since "Line charges" were in effect. Charge for
the number of lines of text that came through the dial up news server or
email server. Before the WWW came along...

And, as we used to point out to those using that as an excuse, before
the "www came along ...":

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?



Tahw?

Hold it in front of an upside down mirror.

On Thu, 17 Nov 2016 08:14:40 -0600, Swingman wrote:

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

I Haven't seen that one in a while, but alas, 'tis still true.


--
Nobody expects the Spanish Inquisition!

On 11/17/2016 11:42 AM, DerbyDad03 wrote:
On Thursday, November 17, 2016 at 11:41:16 AM UTC-5, Leon wrote:
On 11/17/2016 8:14 AM, Swingman wrote:
On 11/16/2016 10:00 PM, Martin Eastburn wrote:
Yes I've been this way since "Line charges" were in effect. Charge for
the number of lines of text that came through the dial up news server or
email server. Before the WWW came along...

And, as we used to point out to those using that as an excuse, before
the "www came along ...":

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?



Tahw?

Hold it in front of an upside down mirror.



LOL. I probably should have remarked, ?tahW

On Thursday, November 17, 2016 at 2:39:34 PM UTC-5, Leon wrote:
On 11/17/2016 11:42 AM, DerbyDad03 wrote:
On Thursday, November 17, 2016 at 11:41:16 AM UTC-5, Leon wrote:
On 11/17/2016 8:14 AM, Swingman wrote:
On 11/16/2016 10:00 PM, Martin Eastburn wrote:
Yes I've been this way since "Line charges" were in effect. Charge for
the number of lines of text that came through the dial up news server or
email server. Before the WWW came along...

And, as we used to point out to those using that as an excuse, before
the "www came along ...":

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?



Tahw?

Hold it in front of an upside down mirror.



LOL. I probably should have remarked, ?tahW

?huh

On 11/16/16 8:00 AM, Leon wrote:
On 11/16/2016 12:58 AM, whit3rd wrote:
On Sunday, November 13, 2016 at 8:11:28 AM UTC-8, Leon wrote:

Fast forward and LED's lights now use, in many cases, yellow filters to
filter out the blue.

Actually, that yellow color is a phosphor; LED illumination starts
with a blue
LED (sharp spectrum line) and generates other wavelengths with phosphors.
Fluorescents start with ultraviolet (from mercury in the gas of the
tube) and
generate visible light with phosphors.



Excuse me for using the wrong terminology. But with out the yellow you
get blue, the point I was trying to make. ;!)

There is no mercy on the wreck!

It is these phosphor mixes that are driving the LED lighting market.
Very difficult and proprietary tech. Need a great UV light source? Get
one of those Phillips bulbs with the phosphor coating on the bulb
envelope and remove that envelop. All the creepy crawlies like scorpions
will glow brightly in you garage/shop at night....


-BR

On 11/14/16 9:00 AM, dadiOH wrote:
"DerbyDad03" wrote in message
...


I have recently bought a couple of these, one 7" and 11".

http://www.homedepot.com/p/Commercia...6241/205890895

About a year ago, I bought 3 of these from HD. They were wire in, not screw
in. I liked them, nice and bright.
http://www.homedepot.com/p/Commercia...L-BN/205148593

Within 3 months, one began flickering badly. Another month or so and a
second began flickering, A month or so later the flickering was so bad that
they were unuseable so both were replaced with similar incandescent bulb
fixtures. The replaced lights had a 5 year warranty but I didn't bother
with it, HD receipt was long gone and even if I had it, the warranty has a
"not OUR fault" clause' moreover, the only remedy was repair or replace and
I didn't want another..

Four or five months later, the third began flickering too. It is still
flickering, light outbut is maybe 10% of the original. It too will be
replaced when I get around to it. That's $90 + 7% tax down the drain. No
more LEDs for me.



LEDs are one of those products where quality varies widely and usually
is in no way related to price. You can always crack one open to
determine quality, but the easiest way is to heed reliable reviews and
look for a good warranty.

-BR

On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

On Thursday, November 17, 2016 at 7:55:20 AM UTC-6, Unquestionably Confused wrote:
On 11/12/2016 5:52 PM, Gramps' shop wrote:
Thanks. Fluorescents are cheaper, but I have decided on the Costco leds.



So, Larry, what's the verdict? Have you purchased and installed those
Costo lights yet?

I'd be interested in hearing your verdict after they're up and running.

Just hung the first one. Instant on, no buzz, no flicker. Plastic housing, but I guess that's OK. Light seems a little "warmer" than the strong white I got with the fluorescent. I'll be curious to see if they last 45 years, but by then I'll be 115 and probably won't remember to check. :-)

For $30, I judge this to be a good deal.

On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.

On 11/19/2016 1:14 PM, Gramps' shop wrote:
On Thursday, November 17, 2016 at 7:55:20 AM UTC-6, Unquestionably Confused wrote:
On 11/12/2016 5:52 PM, Gramps' shop wrote:
Thanks. Fluorescents are cheaper, but I have decided on the Costco leds.



So, Larry, what's the verdict? Have you purchased and installed those
Costo lights yet?

I'd be interested in hearing your verdict after they're up and running.

Just hung the first one. Instant on, no buzz, no flicker. Plastic housing, but I guess that's OK. Light seems a little "warmer" than the strong white I got with the fluorescent. I'll be curious to see if they last 45 years, but by then I'll be 115 and probably won't remember to check. :-)

For $30, I judge this to be a good deal.


I agree with it being a good deal - even better when I paid, IIRC, $26
$28 each for mine.

Out where mine are hanging in the garage, I don't notice the color temp
that much (though I prefer warmer) but you surely will notice the
instant full output if you put them in a cold area like I have.

On Saturday, November 19, 2016 at 5:56:49 PM UTC-5, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.

How do it know?

Simple - I used to design and test semiconductor material -
I started in the mid 70's and went pro in 1980.

I remember some of the first high speed CMOS HMOS and NMOS
that ran really fast but shorted power to ground in the output
transistors in the process. It seemed ok in theory - but after
millions of cycles the part melted the epoxy off the IC !

All semiconductor heats up. It is conducting current. Current flow
causes vibration heating.

Martin

On 11/19/2016 8:14 PM, DerbyDad03 wrote:
On Saturday, November 19, 2016 at 5:56:49 PM UTC-5, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.

How do it know?

In article ,
says...

Simple - I used to design and test semiconductor material -
I started in the mid 70's and went pro in 1980.

I remember some of the first high speed CMOS HMOS and NMOS
that ran really fast but shorted power to ground in the output
transistors in the process. It seemed ok in theory - but after
millions of cycles the part melted the epoxy off the IC !

All semiconductor heats up. It is conducting current. Current flow
causes vibration heating.

But in actual tests is that the major failure
mode of commercial LED lighting?

On Sat, 19 Nov 2016 18:14:24 -0800 (PST), DerbyDad03
wrote:

On Saturday, November 19, 2016 at 5:56:49 PM UTC-5, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.

How do it know?

Well, it's not a Crapsman. ;-)

On Sat, 19 Nov 2016 22:15:59 -0500, "J. Clarke"
wrote:

In article ,
says...

Simple - I used to design and test semiconductor material -
I started in the mid 70's and went pro in 1980.

I remember some of the first high speed CMOS HMOS and NMOS
that ran really fast but shorted power to ground in the output
transistors in the process. It seemed ok in theory - but after
millions of cycles the part melted the epoxy off the IC !

All semiconductor heats up. It is conducting current. Current flow
causes vibration heating.

But in actual tests is that the major failure
mode of commercial LED lighting?

Commercial or residential? I know it's the failure mechanism in
residential LED lighting. Commercial may be better. Or not.

On 11/19/2016 4:56 PM, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so ever.

On Sat, 19 Nov 2016 22:35:52 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 4:56 PM, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so ever.

But you can't touch the junction, which is what counts.

krw wrote:
On Sat, 19 Nov 2016 22:35:52 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 4:56 PM, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so ever.

But you can't touch the junction, which is what counts.


Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.

On Sat, 19 Nov 2016 22:54:21 -0600, Leon wrote:

krw wrote:
On Sat, 19 Nov 2016 22:35:52 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 4:56 PM, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so ever.

But you can't touch the junction, which is what counts.


Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.

The part that creates the light. I don't know what sort of ribbon
light this is but if it's designed for illumination, you can bet the
junction is getting quite hot. If it's just for looks, it may be much
lower power.

On 11/19/2016 5:56 PM, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.


Correct, most High output Leds have heat sinks and the lights themselves
get hot.

A friend bought me a Nitecore flashlight for woodworking I did for him
and some machining. The light from it can light up a building 600 feet
away like daylight. When it's on highpower the glass on the front gets
hot, and the front end gets hot.

Also if you look on youtube you will see led flashlights that require
cooling.

--
Jeff

On 11/19/16 8:47 AM, Leon wrote:


There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

Power supplies are sources of heat, but more likely the devices heat
sink is extended into the base where the power supply is enclosed.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

The LEDs used in ribbons are not high power devices and there are
hundreds of them on a standard 16' reel. Each individual LED is only
dissipating a fraction of a watt.

-BR

On 11/19/16 8:15 PM, J. Clarke wrote:
In article ,
says...

Simple - I used to design and test semiconductor material -
I started in the mid 70's and went pro in 1980.

I remember some of the first high speed CMOS HMOS and NMOS
that ran really fast but shorted power to ground in the output
transistors in the process. It seemed ok in theory - but after
millions of cycles the part melted the epoxy off the IC !

All semiconductor heats up. It is conducting current. Current flow
causes vibration heating.

But in actual tests is that the major failure
mode of commercial LED lighting?


At least for consumer lighting, the failure point is typically the power
supply, more specifically the electrolytic capacitors which dry out and
are degraded by heat. The LEDs do fail, mostly from the same heat
degrading the thermal bond between the actual LED emitter and the heat
sink, but often the root cause of this is poor assembly. LEDs as devices
are very stable and robust, as long as they operate within there design
specs for maximum junction temp.

-BR

On 11/19/16 9:21 PM, krw wrote:
On Sat, 19 Nov 2016 22:15:59 -0500, "J. Clarke"
wrote:



But in actual tests is that the major failure
mode of commercial LED lighting?

Commercial or residential? I know it's the failure mechanism in
residential LED lighting. Commercial may be better. Or not.


The "better" LED lights are those designed as a fixture with the LEDs
separate from the power supplies. It's all heat management. Trying to
cram lots of Lumens into a standard dimension Edison style bulb that is
crammed into a fixture that has no provisions for air flow is really
pushing it.

-BR

On 11/19/16 9:35 PM, Leon wrote:



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so
ever.

I use a lot of these LED strips in lighting projects, never need any
heat sinks.

Specifically the typical LED used in strips is the "3528" surface mount
device. 4 to 8 Lumens at 0.06 to 0.08 Watts of power. Even the "high
density" strips with 600 of these parts (over 16') dissipates less than
50 Watts. Higher power LEDs (5050s) are only 1/4 Watt each.
It is when you get into the arrays (more common in point source
lights/bulbs) that dissipate 12+ Watts that the heat is palpable (it'll
burn your finger, DAMHIK), Physically they are a "blob" about 3/4"
diameter, mounted on a 1" sq. aluminum plate which is thermally bonded
to whatever heat sink the bulb has.

-BR

On 11/19/16 9:54 PM, Leon wrote:
s.


Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.


Those LEDs (3528s) have ceramic cases. The heat is conducted through the
electrical contacts to the copper traces in the ribbon. At 0.08 Watts,
that heat is dissipated quickly.

-BR

On Sat, 19 Nov 2016 22:54:21 -0600, Leon wrote:

Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.

The point where the light is emitted from will be hot. Getting rid of
that heat is the secret of semiconductor life. How much current is at
each led will determine how hot it is, well designed leds lights will
not burn you a bad one will. The higher the current at the led the
shorter the life of the led.

In other words you picked the right led lighting system.

Mark

In article ,
says...

On 11/19/16 8:15 PM, J. Clarke wrote:
In article ,
says...

Simple - I used to design and test semiconductor material -
I started in the mid 70's and went pro in 1980.

I remember some of the first high speed CMOS HMOS and NMOS
that ran really fast but shorted power to ground in the output
transistors in the process. It seemed ok in theory - but after
millions of cycles the part melted the epoxy off the IC !

All semiconductor heats up. It is conducting current. Current flow
causes vibration heating.

But in actual tests is that the major failure
mode of commercial LED lighting?


At least for consumer lighting, the failure point is typically the power
supply, more specifically the electrolytic capacitors which dry out and
are degraded by heat.

Based on forensic analysis of how many failures
of consumer LED replacement bulbs over what span
of time?

The LEDs do fail, mostly from the same heat
degrading the thermal bond between the actual LED emitter and the heat
sink, but often the root cause of this is poor assembly. LEDs as devices
are very stable and robust, as long as they operate within there design
specs for maximum junction temp.

-BR

On 11/20/2016 10:41 AM, Brewster wrote:
On 11/19/16 8:47 AM, Leon wrote:


There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

Power supplies are sources of heat, but more likely the devices heat
sink is extended into the base where the power supply is enclosed.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

The LEDs used in ribbons are not high power devices and there are
hundreds of them on a standard 16' reel. Each individual LED is only
dissipating a fraction of a watt.

Exactly.


-BR




--
Jeff

On 11/20/2016 7:19 AM, krw wrote:
On Sat, 19 Nov 2016 22:54:21 -0600, Leon wrote:

krw wrote:
On Sat, 19 Nov 2016 22:35:52 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 4:56 PM, krw wrote:
On Sat, 19 Nov 2016 09:47:06 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/19/2016 9:33 AM, Brewster wrote:
On 11/13/16 8:43 PM, krw wrote:


It's not about the tube getting hot. It's about the semiconductor
junction heating. Without a *really* good heatsink, they will
overheat. Most are *way* under designed.



An old rule for electronics is 10 sq. inches of heat sink surface
(exposed to room temp) for every Watt of power. Many of the "flood"
style bulbs which don't have the room for this get by with thermal mass.
They don't saturate the heat sink for 1-2 hours, giving you time to get
your lighting task complete before damage begins. This is the bane of
the Edison style bulb for LEDs. Tubes have the surface area going for
them, but the cheaper tubes find a way to skimp on the aluminum to
mitigate any advantages 8^)

-BR



There seems to be a lot of confusion concerning LED's and their heat out
put. I have LED lamps that replaced incandescence bulbs and the light
is cool but the part that converts to the proper voltage generates heat.

I also have probably 20' of high density ribbon LED lights that run on
12 volt and they do not even get warm.

You can bet that the semiconductor junctions are getting warm. The
fact that the surface isn't may also mean that the semiconductors
inside are getting downright toasty. My thermos mug doesn't get warm
on the outside, even when filled with very hot coffee.



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so ever.

But you can't touch the junction, which is what counts.


Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.

The part that creates the light. I don't know what sort of ribbon
light this is but if it's designed for illumination, you can bet the
junction is getting quite hot. If it's just for looks, it may be much
lower power.



Well, not for looks, these light up our kitchen counter tops and the
length of my wife's long arm machine. Lighting is critical on the long
arm machine. But there are hundreds of LED's on that ribbon, IIRC 3 per
inch along 11 feet.

On 11/20/2016 10:05 AM, Brewster wrote:
On 11/19/16 9:54 PM, Leon wrote:
s.


Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.


Those LEDs (3528s) have ceramic cases. The heat is conducted through the
electrical contacts to the copper traces in the ribbon. At 0.08 Watts,
that heat is dissipated quickly.

-BR



Even still, dissipated quickly or not one would think that if you are
touching, pressing your finger hard enough into the ribbon to leave an
imprint that you would feel something.

On 11/20/2016 10:29 AM, Markem wrote:
On Sat, 19 Nov 2016 22:54:21 -0600, Leon wrote:

Define junction on ribbon LED lighting. No where on the ribbon gets
remotely warm.

The point where the light is emitted from will be hot. Getting rid of
that heat is the secret of semiconductor life. How much current is at
each led will determine how hot it is, well designed leds lights will
not burn you a bad one will. The higher the current at the led the
shorter the life of the led.

In other words you picked the right led lighting system.

Mark


I have to think you have the answer. ;~)

Either way, these are the last set I bought, the previous set was from
LeeValley. These weare about 1/2 price compared to :LeeValley

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

On 11/20/2016 10:02 AM, Brewster wrote:
On 11/19/16 9:35 PM, Leon wrote:



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so
ever.

I use a lot of these LED strips in lighting projects, never need any
heat sinks.

Specifically the typical LED used in strips is the "3528" surface mount
device. 4 to 8 Lumens at 0.06 to 0.08 Watts of power. Even the "high
density" strips with 600 of these parts (over 16') dissipates less than
50 Watts. Higher power LEDs (5050s) are only 1/4 Watt each.
It is when you get into the arrays (more common in point source
lights/bulbs) that dissipate 12+ Watts that the heat is palpable (it'll
burn your finger, DAMHIK), Physically they are a "blob" about 3/4"
diameter, mounted on a 1" sq. aluminum plate which is thermally bonded
to whatever heat sink the bulb has.

-BR



Understood but the point I am trying to make is that not all LED
lighting gets hot. I have single bulbs that get hot at the base and
some at best get ever so slightly warm after touching for several
seconds. All of the cool ones are attached to a wood product and stay
on for hundreds/thousands of hours at one time. I get more warmth from
my LCD computer display screen.

On Sun, 20 Nov 2016 08:50:56 -0700, Brewster wrote:

On 11/19/16 9:21 PM, krw wrote:
On Sat, 19 Nov 2016 22:15:59 -0500, "J. Clarke"
wrote:



But in actual tests is that the major failure
mode of commercial LED lighting?

Commercial or residential? I know it's the failure mechanism in
residential LED lighting. Commercial may be better. Or not.


The "better" LED lights are those designed as a fixture with the LEDs
separate from the power supplies. It's all heat management. Trying to
cram lots of Lumens into a standard dimension Edison style bulb that is
crammed into a fixture that has no provisions for air flow is really
pushing it.

No, it's all heat management. Separating the supply from the business
end may, or may not, be part of that.

On Sun, 20 Nov 2016 15:10:07 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/20/2016 10:02 AM, Brewster wrote:
On 11/19/16 9:35 PM, Leon wrote:



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so
ever.

I use a lot of these LED strips in lighting projects, never need any
heat sinks.

Specifically the typical LED used in strips is the "3528" surface mount
device. 4 to 8 Lumens at 0.06 to 0.08 Watts of power. Even the "high
density" strips with 600 of these parts (over 16') dissipates less than
50 Watts. Higher power LEDs (5050s) are only 1/4 Watt each.
It is when you get into the arrays (more common in point source
lights/bulbs) that dissipate 12+ Watts that the heat is palpable (it'll
burn your finger, DAMHIK), Physically they are a "blob" about 3/4"
diameter, mounted on a 1" sq. aluminum plate which is thermally bonded
to whatever heat sink the bulb has.

-BR



Understood but the point I am trying to make is that not all LED
lighting gets hot. I have single bulbs that get hot at the base and
some at best get ever so slightly warm after touching for several
seconds. All of the cool ones are attached to a wood product and stay
on for hundreds/thousands of hours at one time. I get more warmth from
my LCD computer display screen.

No, all get hot. How hot is the difference between ones that will
last and ones that won't. Note that "not that hot" may be enough to
burn a finger (100C or above), if you could touch it.

On 11/20/2016 5:11 PM, krw wrote:
On Sun, 20 Nov 2016 15:10:07 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/20/2016 10:02 AM, Brewster wrote:
On 11/19/16 9:35 PM, Leon wrote:



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so
ever.

I use a lot of these LED strips in lighting projects, never need any
heat sinks.

Specifically the typical LED used in strips is the "3528" surface mount
device. 4 to 8 Lumens at 0.06 to 0.08 Watts of power. Even the "high
density" strips with 600 of these parts (over 16') dissipates less than
50 Watts. Higher power LEDs (5050s) are only 1/4 Watt each.
It is when you get into the arrays (more common in point source
lights/bulbs) that dissipate 12+ Watts that the heat is palpable (it'll
burn your finger, DAMHIK), Physically they are a "blob" about 3/4"
diameter, mounted on a 1" sq. aluminum plate which is thermally bonded
to whatever heat sink the bulb has.

-BR



Understood but the point I am trying to make is that not all LED
lighting gets hot. I have single bulbs that get hot at the base and
some at best get ever so slightly warm after touching for several
seconds. All of the cool ones are attached to a wood product and stay
on for hundreds/thousands of hours at one time. I get more warmth from
my LCD computer display screen.

No, all get hot. How hot is the difference between ones that will
last and ones that won't. Note that "not that hot" may be enough to
burn a finger (100C or above), if you could touch it.


I going to agree that hot is relative. My LED's don't get much more
than room temperature.

On Sun, 20 Nov 2016 19:42:24 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/20/2016 5:11 PM, krw wrote:
On Sun, 20 Nov 2016 15:10:07 -0600, Leon lcb11211@swbelldotnet
wrote:

On 11/20/2016 10:02 AM, Brewster wrote:
On 11/19/16 9:35 PM, Leon wrote:



I cab pinch the ribbon LED beteen my thumb and my finger. Nothing. We
leace these lamps on in our kitchen 24/7 and there is not heat what so
ever.

I use a lot of these LED strips in lighting projects, never need any
heat sinks.

Specifically the typical LED used in strips is the "3528" surface mount
device. 4 to 8 Lumens at 0.06 to 0.08 Watts of power. Even the "high
density" strips with 600 of these parts (over 16') dissipates less than
50 Watts. Higher power LEDs (5050s) are only 1/4 Watt each.
It is when you get into the arrays (more common in point source
lights/bulbs) that dissipate 12+ Watts that the heat is palpable (it'll
burn your finger, DAMHIK), Physically they are a "blob" about 3/4"
diameter, mounted on a 1" sq. aluminum plate which is thermally bonded
to whatever heat sink the bulb has.

-BR



Understood but the point I am trying to make is that not all LED
lighting gets hot. I have single bulbs that get hot at the base and
some at best get ever so slightly warm after touching for several
seconds. All of the cool ones are attached to a wood product and stay
on for hundreds/thousands of hours at one time. I get more warmth from
my LCD computer display screen.

No, all get hot. How hot is the difference between ones that will
last and ones that won't. Note that "not that hot" may be enough to
burn a finger (100C or above), if you could touch it.


I going to agree that hot is relative. My LED's don't get much more
than room temperature.

Again, the surface may not be much more than room temperature but the
surface temperature of the fixture isn't important to the LEDs
reliability.

On 11/20/16 9:31 AM, J. Clarke wrote:
In article ,
says...

On 11/19/16 8:15 PM, J. Clarke wrote:
In article ,
says...

Simple - I used to design and test semiconductor material -
I started in the mid 70's and went pro in 1980.

I remember some of the first high speed CMOS HMOS and NMOS
that ran really fast but shorted power to ground in the output
transistors in the process. It seemed ok in theory - but after
millions of cycles the part melted the epoxy off the IC !

All semiconductor heats up. It is conducting current. Current flow
causes vibration heating.

But in actual tests is that the major failure
mode of commercial LED lighting?


At least for consumer lighting, the failure point is typically the power
supply, more specifically the electrolytic capacitors which dry out and
are degraded by heat.

Based on forensic analysis of how many failures
of consumer LED replacement bulbs over what span
of time?


I follow the LED industry as part curiosity and I also build some custom
LED lighting devices. This means I read a lot of stuff about failures
and always read through the various "tear-down" articles where they
dissect new lamps and also do forensics on failed units. With anything
electronic, the manufactures produce reliability figures (MTBF, mean
time between failures) for components and also degradation numbers tied
to life-killers like heat.

Some of the trade journals touch on this stuff. If you are really
curious (or really bored 8^)

http://www.electronics-eetimes.com/n...t-led-lighting

http://www.osram-os.com/Graphics/XPic6/00102625_0.pdf

http://www.lumileds.com/uploads/167/WP15-pdf

http://www.digikey.com/en/articles/t...ng-led-failure

http://www1.eere.energy.gov/building...e_june2011.pdf

http://d3eurf9v83z5xo.cloudfront.net...eliability.pdf

Some general info, seems reasonable given the source:

https://en.wikipedia.org/wiki/List_of_LED_failure_modes

-BR


The LEDs do fail, mostly from the same heat
degrading the thermal bond between the actual LED emitter and the heat
sink, but often the root cause of this is poor assembly. LEDs as devices
are very stable and robust, as long as they operate within there design
specs for maximum junction temp.

-BR