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.SUBCKT 6P21S-tetrode-VS100V 1 2 3 4 ; A G2 G1 C;
*      Extract V1.990
* Model created: 30-Aug-2014
*
* Traced and model created by Ale Moglia (valves@bartola.co.uk) / www.bartola.co.uk/valves using ExtractModel and uTracer
*
* NOTE: LOG(x) is base e LOG or natural logarithm.
* For some Spice versions, e.g. MicroCap, this has to be changed to LN(x).
X1 1 2 3 4 BTetrodeDE  MU=  9.12 EX=1.298 kG1= 452.1 KP=  41.8 kVB = 2414.5 kG2= 4796.3
+Sc=.66E-01 ap=  .017 w=     0. nu=  2.47 lam=   307.8
+ Ookg1mOokG2=.200E-02 Aokg1=.17E-05 alkg1palskg2=.200E-02 be=  .068 als=  5.34 RGI=2000
+ CCG1=0.0P  CCG2 = 0.0p CPG1 = 0.0p  CG1G2 = 0.0p CCP=0.0P  ;
.ENDS
 
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.SUBCKT BTetrodeDE 1 2 3 4; A G2 G1 C
RE1  7 0  1MEG    ; DUMMY SO NODE 7 HAS 2 CONNECTIONS
E1 7 0 VALUE=
+{V(2,4)/KP*LOG(1+EXP(KP*(1/MU+V(3,4)/SQRT(KVB+V(2,4)*V(2,4)))))}
E2   8 0 VALUE = {Ookg1mOokG2 + Aokg1*V(1,4) - alkg1palskg2*Exp(-be*V(1,4)*SQRT(be*V(1,4)))}
E3   9 0 VALUE = {Sc/kG2*V(1,4)*(1+tanh(-ap*(V(1,4)-V(2,4)/lam+w+nu*V(3,4))))}
G1   1 4 VALUE = {0.5*(PWR(V(7),EX)+PWRS(V(7),EX))*(V(8)-V(9))}
G2   2 4 VALUE = {0.5*(PWR(V(7),EX)+PWRS(V(7),EX))/KG2 *(1+als*Exp(-be*V(1,4) * SQRT(be*V(1,4))))}
RCP  1 4  1G      ; FOR CONVERGENCE	A  - C
C1   3 4  {CCG1}   ; CATHODE-GRID 1	C  - G1
C4   2 4  {CCG2}   ; CATHODE-GRID 2	C  - G2
C5   2 3  {CG1G2}   ; GRID 1 -GRID 2	G1  - G2
C2   1 3  {CPG1}  ; GRID 1-PLATE	G1 - A
C3   1 4  {CCP}   ; CATHODE-PLATE	A  - C
R1   3 5  {RGI}   ; FOR GRID CURRENT	G1 - 5
D3   5 4  DX      ; FOR GRID CURRENT	5  - C
.MODEL DX D(IS=1N RS=1 CJO=10PF TT=1N)
.ENDS BTetrodeDE