close all
clear
clc

% 
Vb_vect = [1:1:10];

% MODEL for 2n2222a transistor
STR1='.MODEL 2n2222a  NPN (IS=2.20f NF=1.00 BF=240 VAF=114';
STR2='+ IKF=0.293 ISE=2.73p NE=2.00 BR=4.00 NR=1.00';
STR3='+ VAR=24.0 IKR=0.600 RE=0.194 RB=0.777 RC=77.7m';
STR4='+ XTB=1.5 CJE=24.9p VJE=1.10 MJE=0.500 CJC=12.4p VJC=0.300';
STR5='+ MJC=0.300 TF=371p TR=64.0n EG=1.12 )';
TransistorModelSTR=sprintf('%s\n%s\n%s\n%s\n',STR1, STR2, STR3, STR4);

% % MODEL for BC108BP transistor
% STR1='.MODEL BC108BP NPN IS =1.8E-14 ISE=5.0E-14 NF =.9955 NE =1.46 BF =400 BR =35.5';
% STR2='+IKF=.14 IKR=.03 ISC=1.72E-13 NC =1.27 NR =1.005 RB =.56 RE =.6 RC =.25 VAF=80';
% STR3='+VAR=12.5 CJE=13E-12 TF =.64E-9 CJC=4E-12 TR =50.72E-9 VJC=.54 MJC=.33';
% TransistorModelSTR=sprintf('%s\n%s\n%s\n',STR1, STR2, STR3);

figure

% Print instructions
for ii = 1:numel(Vb_vect)

  fid = fopen('netlist_test_transistor.net', 'w');
  
  % Write title
  fprintf(fid, 'Transistor test\n')
  
  % Write transistor model
  fprintf(fid, '%s\n', TransistorModelSTR);

  % Write netlist
  fprintf(fid, 'V1 1 0 12\n')
  fprintf(fid, 'Rc 1 2 100\n')
  fprintf(fid, 'Q1 2 3 0 2n2222a\n')
  fprintf(fid, 'Rb 3 4 27000\n')
  fprintf(fid, 'V2 4 0 %f\n', Vb_vect(ii))
  
  fprintf(fid, '.control\n')
  fprintf(fid, 'dc V1 0.01 12 0.01\n')
  fprintf(fid, 'wrdata result (v(1)-v(2))/100  v(2)  (v(4)-v(3))/27000\n')
  fprintf(fid, 'quit\n')
  fprintf(fid, '.endc\n')
  fprintf(fid, '.end\n')

  fclose(fid);

  % Run spice
  system('ngspice netlist_test_transistor.net');

  % Now load and plot the data
  dd = load('result.data'); 

  % Extract data
  ib  = dd(:,6);
  ic  = dd(:,2);
  vce = dd(:,4);

  hold on
  plot(vce, ic*1000, 'k', 'linewidth', 2)
  text(vce(end), ic(end)*1000, [num2str(ib(end)*1e6), ' uA'])
  xlabel('Vce [V]')
  ylabel('Ic [mA]')

end