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LED forward voltage drop with temperature

Started by John S April 22, 2020
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 TrumpLike&#2013266089; unprofessional, immature self... again. You are always stupid, and always childish. Just like Trump.
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 &agrave; 17:40, jlarkin@highlandsniptechnology.com a &eacute;crit&nbsp;: > >> On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr> > >> wrote: > >> > >>> Le 24/04/2020 &agrave; 16:47, Phil Allison a &eacute;crit&nbsp;: > >>>> 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
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 &#2013265920; 17:40, jlarkin@highlandsniptechnology.com a &#2013265929;crit&#2013266080;: >> >> On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr> >> >> wrote: >> >> >> >>> Le 24/04/2020 &#2013265920; 16:47, Phil Allison a &#2013265929;crit&#2013266080;: >> >>>> 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
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 &agrave; 17:40, jlarkin@highlandsniptechnology.com a &eacute;crit&nbsp;: > >> >> On Fri, 24 Apr 2020 17:35:36 +0200, habib <h.bouazizviallet@free.fr> > >> >> wrote: > >> >> > >> >>> Le 24/04/2020 &agrave; 16:47, Phil Allison a &eacute;crit&nbsp;: > >> >>>> 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
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.
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.
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.
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
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&#2013266080; LED_GREEN D(Is=8.2e-25 N=1.46 Rs=5.1 Eg=2.23) > .model&#2013266080; LED_RED&#2013266080;&#2013266080; 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.