# # $Id: electron.demo 3.38.2.6 1992/11/14 02:25:21 woo Exp $ # # Electronics demo # # Bipolar Transistor (NPN) Mutual Characteristic Ie(Vbe)=Ies*exp(Vbe/kT_q) Ic(Vbe)=alpha*Ie(Vbe)+Ico alpha = 0.99 Ies = 4e-14 Ico = 1e-09 kT_q = 0.025 set dummy Vbe set grid set offsets set nolog set nopolar set samples 160 set title "Mutual Characteristic of a Transistor" set xlabel "Vbe (base emmitter voltage)" set xrange [0 : 0.75] set ylabel "Ic (collector current)" set yrange [0 : 0.005] set key .2,.0045 set format y "%.4f" plot Ic(Vbe) set format "%g" pause -1 "Hit return to continue" # Junction Field Effect Transistor (JFET) Mutual Characteristic # drain current above pinch off Ida(Vd)=Ido*(1-Vg/Vp)**2 # drain current below pinch off Idb(Vd)=Ido*(2*Vd*(Vg-Vp)-Vd*Vd)/(Vp*Vp) # drain current Id(Vd)= (Vd>Vg-Vp) ? Ida(Vd) : Idb(Vd) # drain current at zero gate voltage Ido = 2.5 # pinch off voltage Vp = -1.25 # gate voltage Vg = 0 set dummy Vd set nogrid set nokey set offsets 0, 1, 0, 0 set title "JFET Mutual Characteristic" set xlabel "Drain voltage Vd (V)" set xrange [0 : 4] set ylabel "Drain current Id (mA)" set yrange [0 : 5] set label "-0.5 Vp" at 4.1,0.625 set label "-0.25 Vp" at 4.1,1.4 set label "0" at 4.1,2.5 set label "Vg = 0.5 Vp" at 4.1,3.9 plot Vg=0.5*Vp,Id(Vd),Vg=0.25*Vp,Id(Vd),Vg=0,Id(Vd),Vg=-0.25*Vp,Id(Vd) set nolabel pause -1 "Hit return to continue" # amplitude frequency response A(jw) = ({0,1}*jw/({0,1}*jw+p1)) * (1/(1+{0,1}*jw/p2)) p1 = 10 p2 = 10000 set dummy jw set grid set key set logscale xy set offsets 0, 0, 0, 0 set title "Amplitude Frequency Response" set xlabel "jw (radians)" set xrange [1.1 : 90000.0] set ylabel "magnitude of A(jw)" set autoscale y plot abs(A(jw)) pause -1 "Hit return to continue" # phase frequency response set nolog y set logscale x set title "Phase Frequency Response" set ylabel "Phase of A(jw) (degrees)" plot 180/pi*arg(A(jw)) pause -1 "Hit return to continue" # undo what we've done set dummy x set nogrid set offsets 0,0,0,0 set title "" set ylabel "" set xlabel "" set xrange [-10:10] set autoscale xy set key set format xy "%g" set nolabel set nolog