LED forward voltage drop with temperature

[bitrex]

On 4/24/2020 1:35 PM, John Larkin wrote:

On Fri, 24 Apr 2020 18:16:14 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 à 17:40, jlarkin@highlandsniptechnology.com a Êcrit :
On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 à 16:47, Phil Allison a Êcrit :
Jeroen Belleman wrote:

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



Are you sure ? LED is not a silicon based component so I'm not
sure they> have the same tempco.



**FYI:

Silver, copper, gold, aluminium, magnesium, tungsten, zinc, nickel, tin, iron, platinum, mild steel, lead plus some alloys ALL have the same positive tempco of resistance.


Close to .004% per C.

Sure although it is not "%" in that case.

** Pedant.

Pointing out a factor of hundred error


** Only a pedant would bother.

Someone like you.
Only "Allison-100%-wrong", allows himself speaking before thinking! I
suspect the Allison did not really understand what % really mean.


But he wasn't 100% wrong. He was 10,000% wrong.

"Allison Coeff" --> 0.004% gives a coeff = 0.00004; 4.10-5

TC metals (Physics) = (approx.) 0.004; 4.10-3

An error magnitude of 100 between "Allison" and real Physics.


We need a new SI unit of wrongness, Allisons. We can't apply that to
the linux guy, since he is Always Wrong.

Obscure note: electrons conduct heat and electricity, which track. So
most metals and alloys are about 150,000 K/W per ohm.

I suppose then that thermal conductivity should have the same
temperature coefficient as electrical conductivity.

What's the thermal conductivity of a superconductor?

Low-temperature metallic superconductors are lousy thermal conductors;
Pauli exclusion principle, almost all of the lower-energy states are
filled and there aren't many empty states between kT and the energy gap
for the higher energy ones to move into, either.

 

[George Herold]

On Friday, April 24, 2020 at 1:35:41 PM UTC-4, John Larkin wrote:

On Fri, 24 Apr 2020 18:16:14 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 à 17:40, jlarkin@highlandsniptechnology.com a Êcrit :
On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 à 16:47, Phil Allison a Êcrit :
Jeroen Belleman wrote:

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


Are you sure ? LED is not a silicon based component so I'm not
sure they> have the same tempco.



**FYI:

Silver, copper, gold, aluminium, magnesium, tungsten, zinc, nickel, tin, iron, platinum, mild steel, lead plus some alloys ALL have the same positive tempco of resistance.


Close to .004% per C.

Sure although it is not "%" in that case.

** Pedant.

Pointing out a factor of hundred error


** Only a pedant would bother.

Someone like you.
Only "Allison-100%-wrong", allows himself speaking before thinking! I
suspect the Allison did not really understand what % really mean.


But he wasn't 100% wrong. He was 10,000% wrong.

"Allison Coeff" --> 0.004% gives a coeff = 0.00004; 4.10-5

TC metals (Physics) = (approx.) 0.004; 4.10-3

An error magnitude of 100 between "Allison" and real Physics.


We need a new SI unit of wrongness, Allisons. We can't apply that to
the linux guy, since he is Always Wrong.

Don't be too much of a jerk.
Obscure note: electrons conduct heat and electricity, which track. So
most metals and alloys are about 150,000 K/W per ohm.

Explaining the conductivity of metals was one of the first
successes of quantum mechanics. I think the classical prediction
for metal conductivity is off by a factor of ~100.
(Why don't the electrons scatter more in a metal?)

George H.

I suppose then that thermal conductivity should have the same
temperature coefficient as electrical conductivity.

What's the thermal conductivity of a superconductor?

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

John Larkin <jlarkin@highland_atwork_technology.com> wrote in
news:ie86afhtl6av3dr9rn8pncunrlgpp48pbr@4ax.com:

We need a new SI unit of wrongness, Allisons. We can't apply that to
the linux guy, since he is Always Wrong.

Looky. Here is John Larkin, expressing his very TrumpLikeŠ
unprofessional, immature self... again.

You are always stupid, and always childish. Just like Trump.

 

[Bill Sloman]

On Saturday, April 25, 2020 at 8:00:53 AM UTC+10, John Larkin wrote:

On Fri, 24 Apr 2020 14:38:10 -0700 (PDT), George Herold
ggherold@gmail.com> wrote:

On Friday, April 24, 2020 at 1:35:41 PM UTC-4, John Larkin wrote:
On Fri, 24 Apr 2020 18:16:14 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 à 17:40, jlarkin@highlandsniptechnology.com a Êcrit :
On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 à 16:47, Phil Allison a Êcrit :
Jeroen Belleman wrote:

<snip>

We need a new SI unit of wrongness, Allisons. We can't apply that to
the linux guy, since he is Always Wrong.

Don't be too much of a jerk.

Never to sensible people.

The people who don't regard John Larkin as a jerk have to be insensible people - insensitive to his egomania and fatuous point scoring.

John Larkin's idea of "sensible" is much the same as his idea of "correct" - something or somebody he agrees with.

--
Bill Sloman, Sydney

 

[John Larkin]

On Fri, 24 Apr 2020 14:38:10 -0700 (PDT), George Herold
<ggherold@gmail.com> wrote:

On Friday, April 24, 2020 at 1:35:41 PM UTC-4, John Larkin wrote:
On Fri, 24 Apr 2020 18:16:14 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 ŕ 17:40, jlarkin@highlandsniptechnology.com a écrit :
On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr
wrote:

Le 24/04/2020 ŕ 16:47, Phil Allison a écrit :
Jeroen Belleman wrote:

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



Are you sure ? LED is not a silicon based component so I'm not
sure they> have the same tempco.



**FYI:

Silver, copper, gold, aluminium, magnesium, tungsten, zinc, nickel, tin, iron, platinum, mild steel, lead plus some alloys ALL have the same positive tempco of resistance.


Close to .004% per C.

Sure although it is not "%" in that case.

** Pedant.

Pointing out a factor of hundred error


** Only a pedant would bother.

Someone like you.
Only "Allison-100%-wrong", allows himself speaking before thinking! I
suspect the Allison did not really understand what % really mean.


But he wasn't 100% wrong. He was 10,000% wrong.

"Allison Coeff" --> 0.004% gives a coeff = 0.00004; 4.10-5

TC metals (Physics) = (approx.) 0.004; 4.10-3

An error magnitude of 100 between "Allison" and real Physics.


We need a new SI unit of wrongness, Allisons. We can't apply that to
the linux guy, since he is Always Wrong.

Don't be too much of a jerk.

Never to sensible people.

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Phil Allison]

habib is a vile cunt rote:

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

Are you sure ? LED is not a silicon based component so I'm not
sure they> have the same tempco.



**FYI:

Silver, copper, gold, aluminium, magnesium, tungsten, zinc, nickel, tin, iron, platinum, mild steel, lead plus some alloys ALL have the same positive tempco of resistance.


Close to .004% per C.

Sure although it is not "%" in that case.

** Pedant.

Pointing out a factor of hundred error


** Only a pedant would bother.

Someone like you.

Only "Allison-100%-wrong",

** It's fucking TYPO you stinking pile of camel shit.


FOAD ASAP.

 

[Phil Allison]

John Larkin is a Sub Human Moron

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

Obscure note: electrons conduct heat and electricity, which track. So
most metals and alloys are about 150,000 K/W per ohm.

I suppose then that thermal conductivity should have the same
temperature coefficient as electrical conductivity.

** Only an idiot would think that.

Look who just did.

 

[whit3rd]

On Friday, April 24, 2020 at 10:35:41 AM UTC-7, John Larkin wrote:

Obscure note: electrons conduct heat and electricity, which track. So
most metals and alloys are about 150,000 K/W per ohm.

I suppose then that thermal conductivity should have the same
temperature coefficient as electrical conductivity.

What's the thermal conductivity of a superconductor?

That certainly IS an interesting question. It's approximately zero.
The electrons in a superconductor do not share heat with the
lattice because they've become decoupled: the superconducting
transition turns thermal conductivity off, and is a useful thermal switch.

Mobile electrons carry heat, but not mobile Cooper pairs of electrons.

 

[Helmut Sennewald]

Am 22.04.2020 um 17:55 schrieb John S:

LTSpice says that the forward voltage drop of LEDs have a positive
coefficient. That is contrary to my thinking and to my measurements.

Am I doing something wrong?

Hello John,

You can adjust the temperature coefficient with the parameter EG in the
diode's SPICE model. Eg is 1.11 by default. Simply change this number a
little bit until you get the temperature coefficient you need.

Examples:
..model LED_GREEN D(Is=8.2e-25 N=1.46 Rs=5.1 Eg=2.23)
..model LED_RED D(Is=2.4e-20 N=1.655 Rs=1.5 Eg=2.17)

Regards,
Helmut

 

On Sun, 26 Apr 2020 01:30:47 +0200, Helmut Sennewald
<helmutsennewald@t-online.de> wrote:

Am 22.04.2020 um 17:55 schrieb John S:
LTSpice says that the forward voltage drop of LEDs have a positive
coefficient. That is contrary to my thinking and to my measurements.

Am I doing something wrong?

Hello John,

You can adjust the temperature coefficient with the parameter EG in the
diode's SPICE model. Eg is 1.11 by default. Simply change this number a
little bit until you get the temperature coefficient you need.

Examples:
.model LED_GREEN D(Is=8.2e-25 N=1.46 Rs=5.1 Eg=2.23)
.model LED_RED D(Is=2.4e-20 N=1.655 Rs=1.5 Eg=2.17)

Regards,
Helmut

But one would have to carefully measure various real LEDs that are
candidates, then tweak the Spice model to match each one. It's a lot
easier to just try it.

Does Spice account for the temperature coefficient of Rs?



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[John S]

On 4/25/2020 6:30 PM, Helmut Sennewald wrote:

Am 22.04.2020 um 17:55 schrieb John S:
LTSpice says that the forward voltage drop of LEDs have a positive
coefficient. That is contrary to my thinking and to my measurements.

Am I doing something wrong?

Hello John,

You can adjust the temperature coefficient with the parameter EG in the
diode's SPICE model. Eg is 1.11 by default. Simply change this number a
little bit until you get the temperature coefficient you need.

Examples:
.model  LED_GREEN D(Is=8.2e-25 N=1.46 Rs=5.1 Eg=2.23)
.model  LED_RED   D(Is=2.4e-20 N=1.655 Rs=1.5 Eg=2.17)

Regards,
Helmut

Thank you, Helmut. This is valuable info for me.