CHAPTER 7 TRANSISTOR FUNDAMENTALS

Example 7-1, Page 228

In [2]:
VCC=30                  #collector voltage(V)
RC=3                    #Collector resistance (KOhm)

ICsat=VCC/RC            #Saturation current(mA)
VCEc=VCC                #VCE cutoff voltage(V)

print 'Saturation current IC(saturation) = ',ICsat,'mA'
print 'Collector emitter cutoff VCE(cutoff) = ',VCEc,'V'

Saturation current IC(saturation) =  10 mA
Collector emitter cutoff VCE(cutoff) =  30 V

Example 7-2, Page 228

In [3]:
VCC=9                  #collector voltage(V)
RC=3                    #Collector resistance(KOhm)

ICsat=VCC/RC            #Saturation current(mA)
VCEc=VCC                #VCE cutoff voltage(V)

print 'Saturation current IC(saturation) = ',ICsat,'mA'
print 'Collector emitter cutoff VCE(cutoff) = ',VCEc,'V'

Saturation current IC(saturation) =  3 mA
Collector emitter cutoff VCE(cutoff) =  9 V

Example 7-3, Page 229

In [4]:
VCC=15                  #collector voltage(V)
RC=1                    #Collector resistance(KOhm)

ICsat=VCC/RC            #Saturation current(mA)
VCEc=VCC                #VCE cutoff voltage(V)

print 'Saturation current IC(saturation) = ',ICsat,'mA'
print 'Collector emitter cutoff VCE(cutoff) = ',VCEc,'V'

Saturation current IC(saturation) =  15 mA
Collector emitter cutoff VCE(cutoff) =  15 V

Example 7-4, Page 229

In [5]:
VCC=15                  #collector voltage(V)
RC=3                    #Collector resistance(KOhm)

ICsat=VCC/RC            #Saturation current(mA)
VCEc=VCC                #VCE cutoff voltage(V)

print 'Saturation current IC(saturation) = ',ICsat,'mA'
print 'Collector emitter cutoff VCE(cutoff) = ',VCEc,'V'

Saturation current IC(saturation) =  5 mA
Collector emitter cutoff VCE(cutoff) =  15 V

Example 7-5, Page 232

In [20]:
VCC=15.0                 #collector voltage(V)
RC=3                     #collector resistance (KOhm)
VBB=15.0                 #base voltage(V)
RB=1                     #base resistance (MOhm)
Bdc=100                  #current gain

IB1=(VBB/RB)             #base current(uA)
IC1=Bdc*IB1/1000         #Collector current(mA)
VCE1=VCC-(IC1*RC)        #Collector-emitter voltage(V)

IB2=((VBB-0.7)/RB)       #base current(uA)
IC2=Bdc*IB2/1000         #Collector current(mA)
VCE2=VCC-(IC2*RC)        #Collector-emitter voltage(V)

print 'Collector emitter voltage VCE1 = ',VCE1,'V'
print 'For second approx., collector emitter voltage VCE2 = ',VCE2,'V'

Collector emitter voltage VCE1 =  10.5 V
For second approx., collector emitter voltage VCE2 =  10.71 V

Example 7-6, Page 235

In [22]:
VCC=20.0                 #collector voltage(V)
RC=10                    #collector resistance (KOhm)
VBB=10.0                 #base voltage(V)
RB=1                     #base resistance (MOhm)
Bdc=50                   #current gain

IB=(VBB/RB)             #base current(uA)
IC=Bdc*IB/1000          #Collector current(mA)
VCE=VCC-(IC*RC)         #Collector-emitter voltage(V)

print 'Collector emitter voltage VCE = ',VCE,'V'
print 'So, transistor is in active region.'

Collector emitter voltage VCE =  15.0 V
So, transistor is in active region

Example 7-7, Page 235

In [32]:
VCC=20.0                 #collector voltage(V)
RC=5                     #collector resistance (KOhm)
VBB=10.0                 #base voltage(V)
RB=100                   #base resistance(KOhm)
Bdco=50                  #old current gain

ICsat=VCC/RC             #Saturation current(mA)
IB=VBB/RB                #base current(mA)
IC=Bdc*IB/1000           #Collector current(mA)
VCE=VCC-(IC*RC)          #Collector-emitter voltage(V)
Bdcn=ICsat/IB            #New current gain
   

print 'ICsat = ',ICsat,'mA'
print 'Bdc = ',int(Bdcn)
print 'Current can not be more than ICsat So, current gain will decrease.'
print 'So, transistor has two current gain: active region & saturation region.'

ICsat =  4.0 mA
Bdc =  40
Current can not be more than ICsat So, current gain will decrease.
So, transistor has two current gain: active region & saturation region.

Example 7-8, Page 236

In [1]:
VCC=5.0                  #collector voltage(V)
ICEO=50                  #Collector leakage current(nA)
RC=1                     #collector resistance (KOhm)
VBB=10.0                 #base voltage(V)
RB=10                    #base resistance(KOhm)
VCEs=0.15                #VCE saturation(V)

VCE=VCC-((ICEO*RC)*10**-6)        #Collector-emitter voltage(V)

print 'Two values of output voltage are 0 and 5 V'
print 'first voltage is voltage across saturated transistor = ',VCEs,'V' 
print 'Second voltage is: VCE = ',round(VCE,2),'V'

Two values of output voltage are 0 and 5 V
first voltage is voltage across saturated transistor =  0.15 V
Second voltage is: VCE =  5.0 V

Example 7-9, Page 239

In [42]:
VCC=15                  #collector voltage(V)
VBB=5                   #Base voltage(V)
RC=2                    #collector resistance (KOhm)
VBE=0.7                 #base voltage(V)
RB=100                  #base resistance(KOhm)
RE=1                    #emitter resistance(KOhm)


VE=VBB-VBE               #Emitter voltage(V)
IE=(VE/RE)               #emitter current(mA)
IC=IE                    #Collector current(mA)
VC=VCC-(IC*RC)           #Collector-emitter voltage(V)
VCE=VC-VE                #Collector-emitter voltage(V)
   

print 'Emitter current IE = ',IE,'mA'
print 'Emitter voltage VE = ',VE,'V'
print 'Collector emitter voltage VCE = ',VCE,'V'

Emitter current IE =  4.3 mA
Emitter voltage VE =  4.3 V
Collector emitter voltage VCE =  2.1 V

Example 7-10, Page 242

In [48]:
VCC=20                   #collector voltage(V)
VBB=15                   #Base voltage(V)
VBE=0.7                  #base voltage(V)
RE=1.5                   #emitter resistance(KOhm)
IE=25.0                    #emitter current(mA)

VE=IE*RE                         #emitter current(mA)
RE=(VBB/IE)*1000                 #emitter resistance(KOhm)
RE2=((VBB-VBE)/IE)*1000          #emitter resistance(KOhm)
   
print 'Emitter voltage VE = ',VE,'V'
print 'Emitter resistance RE = ',RE,'Ohm'
print 'Emitter resistance RE2 = ',RE2,'Ohm'

Emitter voltage VE =  37.5 V
Emitter resistance RE =  600.0 Ohm
Emitter resistance RE2 =  572.0 Ohm