From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001 From: priyanka Date: Wed, 24 Jun 2015 15:03:17 +0530 Subject: initial commit / add all books --- 339/CH7/EX7.4/ex7_4.sce | 79 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) create mode 100755 339/CH7/EX7.4/ex7_4.sce (limited to '339/CH7/EX7.4') diff --git a/339/CH7/EX7.4/ex7_4.sce b/339/CH7/EX7.4/ex7_4.sce new file mode 100755 index 000000000..ee8f7bfae --- /dev/null +++ b/339/CH7/EX7.4/ex7_4.sce @@ -0,0 +1,79 @@ +//first we define all parameters for the transistor and the circuit +Z0=50; //characteristic imedance of the system + +Vcc=3.6; //power supply voltage +Vce=2; //collector voltage +Ic=10e-3; //collector current + +T=300; //ambient temperature (300K) + +//transistor parameters (they are very similar to BFG403W) +beta=145; // current gain +Is=5.5e-18; // saturation current +VAN= 30; // forward Early voltage +tau_f=4e-12; // forward transition time +rb=125; // base resistance +rc=15; // collector resistance +re=1.5; // emitter resistance +Lb=1.1e-9; // base inductance +Lc=1.1e-9; // collector inductance +Le=0.5e-9; // emitter inductance +Cjc=16e-15; // collector junction capacitance at zero applied voltage +mc=0.2; // collector junction grading coefficient +Cje=37e-15; // emitter junction capacitance at zero applied voltage +me=0.35; // emitter junction grading coefficient +phi_be=0.9; // base-emitter diffusion potential +phi_bc=0.6; // base-collector diffusion potential +Vbe=phi_be; // base-emitter voltage + +// some physical constants +k=1.38e-23; // Boltzmann's constant +q=1.6e-19; // elementary charge +VT=k*T/q; // thermal potential + +disp('DC biasing parameters'); + +Ib=Ic/beta; +disp("Amperes",Ib,"Base current"); + +Rc=(Vcc-Vce)/Ic; +disp("Ohms",Rc,"Collector resistance"); + +Rb=(Vcc-Vbe)/Ib; +disp("Ohms",Rb,"Base resistance"); + + +r_pi=VT/Ib; +disp("Ohms",r_pi,"Rpi"); + +r0=VAN/Ic; +disp("Ohms",r0,"R0"); + +gm=beta/r_pi; +disp("Mho",gm,"Gm"); + +Vbc=Vbe-Vce; +Cmu=Cjc*(1-Vbc/phi_bc)^(-mc); +disp("Farads",Cmu,"base collector capacitance"); + +if(Vbe<0.5*phi_be) + Cpi_junct=Cje*(1-Vbe/phi_be)^(-me); +else + C_middle=Cje*0.5^(-me); + k_middle=1-0.5*me; + Cpi_junct=C_middle*(k_middle+me*Vbe/phi_be); +end; + +disp("Farads",Cpi_junct,"Junction Capacitance"); + +Cpi_diff=Is*tau_f/VT*exp(Vbe/VT); +disp("Farads",Cpi_diff,"Differential capacitance"); + +Cpi=Cpi_junct+Cpi_diff; +disp("Farads",Cpi,"Total Capacitance"); + +C_miller=Cmu*(1+gm*r_pi/(r_pi+rb)*Z0*r0/(r0+rc+Z0)); +disp("Farads",C_miller,"Miller Capacitance"); + +C_input=Cpi+C_miller; +disp("Farads",C_input,"Total input capacitance"); \ No newline at end of file -- cgit