# Chapter 13 - Non-linear Analog Systems¶

## Example 13_1 Page No. 395¶

In [3]:
from math import log
from __future__ import division
VT=26*10**(-3)
print "VT= %0.2f"%(VT)," volts" # Thermal voltage
R1=5*10**(3)
print "R1= %0.2f"%(R1)," ohm"  # resistance
Iso=1*10**(-10)
print " Iso = %0.2e"%(Iso)," ampere" # Scale factor (as current)directly proportional to cross-section area of EBJ

print "part(i)"
vs=1*10**(-3)
print "vs= %0.2e"%(vs)," volts" # Input voltage1
vo=-VT*(log(vs/(Iso*R1)))
print "vo=-VT*(log(vs/(Iso*R1)))= %0.2f"%(vo)," volts" # Output voltage of Log OP-AMP for input1 i.e vs = 1 mV

print "part(ii)"
vs=10*10**(-3)
print "vs= %0.2e"%(vs)," volts" # Input voltage2
vo=-VT*(log(vs/(Iso*R1)))
print "vo=-VT*(log(vs/(Iso*R1)))= %0.2f"%(vo)," volts" # Output voltage of Log OP-AMP for input1 i.e vs = 10 mV

print "part(iii)"
vs=100*10**(-3)
print "vs= %0.2f"%(vs)," volts" # Input voltage3
vo=-VT*(log(vs/(Iso*R1)))
print "vo=-VT*(log(vs/(Iso*R1)))= %0.2f"%(vo)," volts" # Output voltage of Log OP-AMP for input1 i.e vs = 100 mV

print "part(iv)"
vs=1
print "vs= %0.2f"%(vs)," volts" # Input voltage4
vo=-VT*(log(vs/(Iso*R1)))
print "vo=-VT*(log(vs/(Iso*R1)))= %0.2f"%(vo)," volts" # Output voltage of Log OP-AMP for input1 i.e vs = 1V

VT= 0.03  volts
R1= 5000.00  ohm
Iso = 1.00e-10  ampere
part(i)
vs= 1.00e-03  volts
vo=-VT*(log(vs/(Iso*R1)))= -0.20  volts
part(ii)
vs= 1.00e-02  volts
vo=-VT*(log(vs/(Iso*R1)))= -0.26  volts
part(iii)
vs= 0.10  volts
vo=-VT*(log(vs/(Iso*R1)))= -0.32  volts
part(iv)
vs= 1.00  volts
vo=-VT*(log(vs/(Iso*R1)))= -0.38  volts


## Example 13_2 Page No. 396¶

In [4]:
from math import log
from __future__ import division
VT=26*10**(-3)
print "VT= %0.2f"%(VT)," volts" # Thermal voltage
R1=100*10**(3)
print "R1= %0.2f"%(R1)," ohm"  # resistance
Iso=50*10**(-9)
print " Iso = %0.2e"%(Iso)," ampere" # Scale factor (as current)directly proportional to cross-section area of EBJ
vs=2.5
print "vs= %0.2f"%(vs)," volts" # Input voltage
vo=-VT*(log(vs/(Iso*R1)))
print "vo=-VT*(log(vs/(Iso*R1)))= %0.2f"%(vo)," volts" # Output voltage of Log OP-AMP for input1 i.e vs = 2.5 V

VT= 0.03  volts
R1= 100000.00  ohm
Iso = 5.00e-08  ampere
vs= 2.50  volts
vo=-VT*(log(vs/(Iso*R1)))= -0.16  volts


## Example 13_3 Page No. 397¶

In [1]:
from math import exp
from __future__ import division
VT=26*10**(-3)
print "VT= %0.2f"%(VT)," volts" # Thermal voltage
RF=100*10**(3)
print "RF= %0.2e"%(RF)," ohm"  # resistance
Iso=50*10**(-9)
print " Iso = %0.2e"%(Iso)," ampere" # Scale factor (as current)directly proportional to cross-section area of EBJ
vs=-0.162
print "vs= %0.2f"%(vs)," volts" # Input voltage
vo=Iso*RF*(exp(-vs/VT))
print "vo=Iso*RF*(exp(-vs/VT))= %0.2f"%(vo)," volts" # Output voltage of Antilog OP-AMP for input1 i.e vs = -0.162 V

VT= 0.03  volts
RF= 1.00e+05  ohm
Iso = 5.00e-08  ampere
vs= -0.16  volts
vo=Iso*RF*(exp(-vs/VT))= 2.54  volts