Chapter 1: Semiconductor Basics

Example 1.1(a), Page Number:29

# variable declaration
V_bias=10.0;      #bias voltage in volt
R_limit=1000;   #limiting resistance in ohm
r_d =10.0;        #r_d value

#calculation
#IDEAL MODEL
print "IDEAL MODEL"
V_f=0;          #voltage in volt
I_f=V_bias/R_limit;  #foward current
V_R_limit=I_f*R_limit;  #limiting voltage
print "forward voltage = %.2f volts" %V_f
print "forward current = %.2f amperes" %I_f
print "voltage across limiting resistor = %.2f volts" %V_R_limit

#PRACTICAL MODEL
print "\nPRACTICAL MODEL"
V_f=0.7;      #voltage in volt
I_f=(V_bias-V_f)/R_limit;   #foward current
V_R_limit=I_f*R_limit;      #limiting voltage
print "forward voltage = %.2f volts" %V_f
print "forward current = %.3f amperes" %I_f
print "voltage across limiting resistor = %.2f volts" %V_R_limit

#COMPLETE MODEL
print "\nCOMPLETE MODEL"
I_f=(V_bias-0.7)/(R_limit+r_d);  #foward current
V_f=0.7+I_f*r_d;                 #forward voltage
V_R_limit=I_f*R_limit;            #limiting voltage
print "forward voltage = %.3f volts" %V_f
print "forward current = %.3f amperes" %I_f
print "voltage across limiting resistor = %.2f volts" %V_R_limit

IDEAL MODEL
forward voltage = 0.00 volts
forward current = 0.01 amperes
voltage across limiting resistor = 10.00 volts

PRACTICAL MODEL
forward voltage = 0.70 volts
forward current = 0.009 amperes
voltage across limiting resistor = 9.30 volts

COMPLETE MODEL
forward voltage = 0.792 volts
forward current = 0.009 amperes
voltage across limiting resistor = 9.21 volts

Example 1.1(b), Page Number:29

# variable declaration
V_bias=5;     #bias voltage in volt
I_R=1*10**-6; #current
R_limit=1000   #in Ohm

#calculation
#IDEAL MODEL
print "IDEAL MODEL"
I_r=0.0;   #current in ampere
V_R=V_bias;   #voltages are equal
V_R_limit=I_r*R_limit;   #limiting voltage
print "Reverse voltage across diode = %.2f volts" %V_R
print "Reverse current through diode= %.2f amperes" %I_r
print "voltage across limiting resistor = %.2f volts" %V_R_limit

#PRACTICAL MODEL
print "\nPRACTICAL MODEL"
I_r=0.0;         #current in ampere
V_R=V_bias;    #voltages are equal
V_R_limit=I_r*R_limit;   #limiting voltage
print "Reverse voltage across diode= %.2f volts" %V_R
print "Reverse current through diode = %.2f amperes" %I_r
print "voltage across limiting resistor = %.2f volts" %V_R_limit

#COMPLETE MODEL
print "\nCOMPLETE MODEL"
I_r=I_R;       #current in ampere
V_R_limit=I_r*R_limit;    #limiting voltage
V_R=V_bias-V_R_limit;     #voltage in volt
print "Reverse voltage across diode = %.3f volts" %V_R
print "Reverse current through diode = %d micro Amp" %(I_r*10**6)
print "voltage across limiting resistor = %d mV" %(V_R_limit*1000)

IDEAL MODEL
Reverse voltage across diode = 5.00 volts
Reverse current through diode= 0.00 amperes
voltage across limiting resistor = 0.00 volts

PRACTICAL MODEL
Reverse voltage across diode= 5.00 volts
Reverse current through diode = 0.00 amperes
voltage across limiting resistor = 0.00 volts

COMPLETE MODEL
Reverse voltage across diode = 4.999 volts
Reverse current through diode = 1 micro Amp
voltage across limiting resistor = 1 mV