Installing and using LTspice IV (now including LTXVII), From beginner to advanced

[benb]

@jan.didden , I would rather think that the people behind LTspice have finally figured out that they have many users that have lived with LTspice for 25 years and don't want to loose them for silly reasons like changed icons and keyboard shortcuts, besides basic compatibility of operation (which now finally they managed to implement, after years of intermediate crap versions).

It did come up with a couple "installation" questions, one was use new "more intuitive" keyboard shortcuts or original ones. I'm in favor of improved and better interfaces, but yeah, I've used the original LTspice for so long it feels normal. I taught a short LTspice class 10 years ago, and was reminded how bad it is when seeing someone struggle running a wire and trying to go from horizontal to vertical - "Oh yeah, you have to click where you want to end a line segment, then you can go another direction." It had become so basic to me I forgot to mention it.

 

[gerhard]

When Mike Engelhard feels after 25 years that it's time for something
completely new I'm willing to check it.

< https://forum.qorvo.com/ >

For boards I use Altium Designer that has built-in Spice, but it seems
it never caught on.

But first, I must get rid of VMware 17. THE performance killer
if there ever was one.

Gerhard

 

[Hearinspace]

Being a once a year, run somebody else's file sort of LTspice user, plus a once a year Windows user, I have never got the hang of navigating directories.

Working on Mac with a current project I have an asc file that was given to me and a tube model I just got yesterday that has a LOT of extra text in it. My question is what to delete from the text so that I can copy and paste it to the asc as a directive? Thanks.

Here's the text of the file:

*7963 LTspice model based on the generic triode model from Adrian Immler, version i2
*A version log is at the end of this file
*Params fitted to measured values of a Sylvania sample by Adrian Immler, Oct. 2018
*The high fit quality is presented at adrianimmler.simplesite.com
*History's best of tube decribing art (plus some new ideas) is merged to this new approach.
*@ neg. Vg, Ia accuracy is similar to Koren or Ayumi models.
*@ small neg. Vg, the "Anlauf" current is considered.
*@ pos. Vg, Ig and Ia accuracy is on a unrivaled level.
*This offers new simulation possibilities like bias point setting with MOhm grid resistor,
*Audion radio circuits, low voltage amps, guitar distortion stages or pulsed stages.

• anode (plate)
• | grid
• | | cathode
• | | |

.subckt 7963_i2 A G K
.params
*Parameters for the space charge current @ Vg <= 0

• mu = 46.35 ;Determines the voltage gain @ constant Ia
• rad = 1000 ;Differential anode resistance, set @ Iad and Vg=0V
• Vct = -0.119 ;Offsets the Ia-traces on the Va axis. Electrode material's contact potential
• kp = 329 ;Mimics the island effect
• xs = 1.65 ;Determines the curve of the Ia traces. Typically between 1.2 and 1.8

*
*Parameters for assigning the space charge current to Ia and Ig @ Vg > 0

• kB = 1 ;Describes how fast Ia drops to zero when Va approaches zero.
• radl = 259 ;Differential resistance for the Ia emission limit @ very small Va and Vg > 0
• tsh = 20 ;Ia transmission sharpness from 1th to 2nd Ia area. Keep between 3 and 20. Start with 20.
• xl = 1 ;Exponent for the emission limit

*
*Parameters of the grid-cathode vacuum diode

• Rgi = 35 ;Internal grid resistor. Causes an Ia reduction @ Ig > 0.
• kg = 100 ;Inverse scaling factor for the Va independent part of Ig (caution - interacts with xg!)
• Vctg = -0.404 ;Offsets the log Ig-traces on the Vg axis. Electrode material's contact potential
• xg = 2.4 ;Determines the curve of the Ig slope versus (positive) Vg and Va >> 0
• VT = 0.128 ;Log(Ig) slope @ Vg<0. VT=k/q*Tk (cathodes absolute temp, typically 1150K)

*
*Parameters for the caps

• cag = 0p75 ;From datasheet. May lead to gain-decrease @ highest audible frequencies!
• cak = 0p25 ;From datasheet
• cgk = 1p6 ;From datasheet

*
*Calculated parameters

• Iad = 100/rad ;Ia where the anode a.c. resistance is set according to rad.
• ks = pow(mu/(rad*xs*Iad**(1-1/xs)),-xs) ;Reduces the unwished xs influence to the Ia slope
• ksnom = pow(mu/(rad*1.5*Iad**(1-1/1.5)),-1.5) ;Sub-equation for calculating Vg0
• Vg0 = Vct + (Iad*ks)(1/xs) - (Iad*ksnom)(2/3) ;Reduces the xs influence to Vct.
• kl = pow(1/(radl*xl*Ild**(1-1/xl)),-xl) ;Reduces the xl influence to the Ia slope @ small Va
• Ild = sqrt(radl)*1m ;Current where the Il a.c. resistance is set according to radl.

*
*Space charge current model
Bggi GGi 0 V=v(Gi,K)+Vg0 ;Effective internal grid voltage.
Bahc Ahc 0 V=uramp(v(A,K)) ;Anode voltage, hard cut to zero @ neg. values
Bst St 0 V=max(v(GGi)+v(Ahc)/(mu), v(Ahc)/kp*ln(1+exp(kp*(1/mu+v(GGi)/(1+v(Ahc))))));Steering volt.
Bs Ai K I=ft1()/ks*pow(v(St),xs) ;Langmuir-Childs law for the space charge current Is
.func ft1() {1+(1+tanh(4*v(GGi)))/20} ;Finetuning-function for better overall fit at pos Vg
*
*Anode current limit @ small Va
.func smin(x,y,k) {pow(pow(x+1f, -k)+pow(y+1f, -k), -1/k)} ;Min-function with smooth trans.
Ra A Ai 1
Bgl Gi A I=min(i(Ra)-smin(1/kl*pow(v(Ahc),xl),i(Ra),tsh),i(Bgvd)*exp(4*v(G,K))) ;Ia emission limit
*
*Grid model
Rgi G Gi {Rgi} ;Internal grid resistor for "Ia-reduction" @ Vg > 0
.func Ivd(Vvd, kvd, xvd, VTvd) {1/kvd*pow(VTvd*xvd*ln(1+exp(Vvd/VTvd/xvd)),xvd)} ;Vacuum diode function
Bgvd Gi K I=Ivd(v(G,K)+Vctg-1m*sqrt(v(Ahc)), kg, xg, VT) ;Grid-cathode vacuum diode
.func ft2() {7*(1-tanh(3*(v(G,K)+Vg0)))} ;Finetuning-func. improves ig-fit @ Vg near -0.5V, low Va.
Bgr Gi Ai I=ft1()*ivd(v(GGi),ks, xs, 0.8*VT)/(1+ft2()+kB*v(Ahc));Is reflection to grid when Va approaches zero
Bs0 Ai K I=ft1()*ivd(v(GGi),ks, xs, 0.8*VT)/(1+ft2()) - ft1()/ks*pow(v(GGi),xs) ;Compensates neg Ia @ small Va and Vg near zero

*Caps
C1 A G {cag}
C2 A K {cak}
C3 G K {cgk}
.ends
*
*Version log
*i1 :Initial version
*i2 in order changed to the more common order „A G K“ (Thanks to Markus Gyger for his tip)

 

[Sorento]

No need to delete anything.
Every line with an Asterisk * in front is so marked as a comment and ignored by LTSpice.

 

[Hearinspace]

Ahaah, I see. Great. Thanks very much!

 

[Zung]

Well done!
I didn't know the bullet points are ignored by the parser.

 

[Mooly]

Has anyone had any issue with the latest LT update creating a completely new installation in the Program Files rather than the AppData area?

I now have two versions, one new and up to date and one that says it is up to date but isn't. The 'new' version has carried over everything from the original AppData setup.

Could this be because I selected 'Install for everyone using Admin Option' which was the recommended choice rather than the 'Just for me' option although I'm sure I've used that option before. I've added this over on the LT forums because I've seen others complain over this.

 

[Mooly]

Just to add to the above... now fixed thanks to Macrium (restored back to previous disk image). If there are any comments over at LT I will update this thread.