Model Paint version for rectifier spice modeling

[Bluesystems]

Is there a model paint version with the ability to model a rectifier.
I see it does triodes and pentodes but how about a simple rectifier?
Be nice to make quick accurate rectifier spice models from a data sheet.

Thanks for any help.

 

[euro21]

Have you read this yet?

 

[Ray Waters]

Have you read this yet?

Bad link. This is what I get:

 

[Francois G]

Is there a model paint version

What is “model paint”? Obviously I can’t help, but I would like to know what you are asking.

 

[Ray Waters]

This might be what the OP is asking about.

Model Paint Tools: Trace Tube Parameters over Plate Curves, Interactively

 

[euro21]

Bad link. This is what I get:

Sorry.
http://digilander.libero.it/paeng/vacuum_diode_models.htm

Tube rectifiers model usually similar as diode model.

 

[Bluesystems]

Tube rectifiers model usually similar as diode model.

Yes diode and rectifier are different names for the same device.

Thank you for the link to the math. I am familiar with this interesting WEB site.
For me the math is not the main difficulty. The main difficulty is finding the correct math coefficients for any one diode model that results in curves that match the data sheet. I was not able to see how the WEB site provided a process to find the correct coefficients for the required math.

Model paint provides a nice and quick graphical way to find correct math coefficients for a triode that results in spice model curves that match data sheet curves.
This is very useful in my experience for triodes.

I had hoped to use Model paint to find the correct coefficients for simple rectifiers.

I did come up with a work around for Model paint. It is not very elegant yet does allow the quick creation of the correct coefficients for simple rectifiers.

1) Start with the default triode model.
2) Set the grid voltage sweep to zero volts only.
3) Set the Va sweep to what ever the data sheet shows.

4) Import the data sheet graphic into model paint. A 5U4GB is shown for example has Va = 0-140V.
5) Adjust the model sliders to get a good curve match. This is pretty quick for a simple rectifier.
6) Create the model in Model paint and copy it into a text file.
7) Edit the text file to remove the grid entry (2) in the .SUBCKT statement and set the name you wish to use for your new model.
".SUBCKT 5U4EXSINGLE 1 3 ; Plate Grid-NOT USED Cathode"
8) Add a 1 ohm resistor, R100 to tie the grid (2) to the cathode (3) turning this into a diode from a triode.
"R100 2 3 1 ; tie grid to cathode"
9) Save the file. You now have a diode model for your rectifier.

** TEST ****************************************

• Created on 01/03/2025 16:33 using paint_kit.jar 3.1
• www.dmitrynizh.com/tubeparams_image.htm
• Plate Curves image file:
• Data source link:

*----------------------------------------------------------------------------------
.SUBCKT 5U4EXSINGLE 1 3 ; Plate Grid-NOT USED Cathode

• + PARAMS: CCG=3P CGP=1.4P CCP=1.9P RGI=2000
• + MU=2.744 KG1=1030.2 KP=2.8 KVB=8.1 VCT=0.0425 EX=1.556
• * Vp_MAX=140 Ip_MAX=1000 Vg_step=1 Vg_start=0 Vg_count=1
• * Rp=4000 Vg_ac=55 P_max=40 Vg_qui=-48 Vp_qui=300
• * X_MIN=63 Y_MIN=16 X_SIZE=915 Y_SIZE=651 FSZ_X=1353 FSZ_Y=848 XYGrid=true
• * showLoadLine=n showIp=y isDHT=n isPP=n isAsymPP=n showDissipLimit=n
• * showIg1=n gridLevel2=n isInputSnapped=n
• * XYProjections=n harmonicPlot=n dissipPlot=n

*----------------------------------------------------------------------------------
E1 7 0 VALUE={V(1,3)/KP*LOG(1+EXP(KP*(1/MU+(VCT+V(2,3))/SQRT(KVB+V(1,3)*V(1,3)))))}
RE1 7 0 1G ; TO AVOID FLOATING NODES
R100 2 3 1 ; tie grid to cathode
G1 1 3 VALUE={(PWR(V(7),EX)+PWRS(V(7),EX))/KG1}
RCP 1 3 1G ; TO AVOID FLOATING NODES
C1 2 3 {CCG} ; CATHODE-GRID
C2 2 1 {CGP} ; GRID=PLATE
C3 1 3 {CCP} ; CATHODE-PLATE
D3 5 3 DX ; POSITIVE GRID CURRENT
R1 2 5 {RGI} ; POSITIVE GRID CURRENT
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS
*$

Yes this results in a overly complex model that is computationally inefficient.
It does however simulate well with results that match both the GE data sheet from the 1960s and matches measurements of a real NOS GE 5U4GB rectifier on the bench.
I expect it will work equally well for any other rectifier that you have a clean and accurate Va/Ia curve for.

Now back to my original post.
It would be nice to be able to use Model paint without my workaround. Anyone know if this is a available function in Model paint?