I've been modeling an LED (in Eagle) for a high school class I'm teaching. I found this "file" and imported it into the general diode model. It works, but doesn't exactly match values that I measure on a breadboard.

*Red LED
.MODEL DMOD D (IS=93.2P RS=42M N=3.73 BV=4 IBV=10U
+ CJO=2.97P VJ=.75 M=.333 TT=4.32U)
.MODEL DMOD D

The model puts out a Vf=1.8v for 20mA, and Vf=1.7v for 7mA.

I'm probably splitting hairs, but I'm just trying to understand what all those values in the model mean.

 

So here's the simulation results for 3 different LED's, although the BLUE and WHITE give the same values.
RED has 20 mA
White and BLue have 10 mA.
Total current adds up to 40 mA as shown.

 

What's the problem?
Did you use the different models for RED, BLUE, and WHITE, as required?

 

Check out this explanation of SPICE parameters. It is the best I've found so far.

https://global.oup.com/us/companion.websites/9780195131864/pdf/cem.pdf

 

It works, but doesn't exactly match values that I measure on a breadboard.

It would be rare for a simulation to agree exactly, or even closely, with an actual breadboard.

 

Yeah ok, it seems close. I'll have to dig into that link that @Papabravo has.
Thanks for the reply!

 

Here are the values I found, for reference:

*Typ RED GaAs LED: Vf=1.7V Vr=4V If=40mA trr=3uS
.MODEL LED1 D (IS=93.2P RS=42M N=3.73 BV=4 IBV=10U
+ CJO=2.97P VJ=.75 M=.333 TT=4.32U)

*Typ RED,GREEN,YELLOW,AMBER GaAs LED: Vf=2.1V Vr=4V If=40mA trr=3uS
.MODEL LED2 D (IS=93.1P RS=42M N=4.61 BV=4 IBV=10U
+ CJO=2.97P VJ=.75 M=.333 TT=4.32U)

*Typ BLUE SiC LED: Vf=3.4V Vr=5V If=40mA trr=3uS
.MODEL LED3 D (IS=93.1P RS=42M N=7.47 BV=5 IBV=30U
+ CJO=2.97P VJ=.75 M=.333 TT=4.32U)

 

FWIW, here is a plot of the simulation of these 3 LED's.