Chapter-15 Power Supplies(Voltage Regulators)

Example-15.1 Page Number-774

In [10]:
Vrms=1.5            #in volts
Vdc=25              #in volts

#Ripple of y=the filter r:
r=(Vrms/Vdc)*100        #in %

print "Ripple of y=the filter r:",r,"%"

Ripple of y=the filter r: 6.0 %

Example-15.2 Page Number-775

In [4]:
Vnl=60.0            #no load voltage in volts
Vfl=56.0            #full voltage in volts
#Voltage Regulation(V.R):
VR=((Vnl-Vfl)/Vfl)*100

print "Voltage Regulation(V.R):",round(VR,1),"%"

Voltage Regulation(V.R): 7.1 %

Example-15.3 Page Number-777

In [6]:
I=50               #in mA(Current Drawn)
C=100              #in microF(Field Capacitor)
#for the Full Wave Rectifier:
#Ripple Voltage V:
V=(2.4*I)/C         #in volts

print "Ripple Factor V=",V,"V"

Ripple Factor V= 1.2 V

Example-15.4 Page Number-778

In [9]:
Vm=30                #in volts(Peak Rectified Voltage)
I=50               #in mA(Current Drawn)
C=100              #in microF(Field Capacitor)

#for the Full Wave Rectifier:
#Filter Dc voltage V:

V=Vm-(4.17*I)/C        #in volts
print "Filter Dc voltage V:",round(V,1),"V"

Filter Dc voltage V: 27.9 V

Example-15.5 Page Number-778

In [15]:
Vm=30                #in volts(Peak Rectified Voltage)
I=50                #in mA(Current Drawn)
C=100                 #in microF(Field Capacitor)
Vdc=27.9             #in volts
#for the Capacity Filter :
#Ripple of the Filter R:
r=(2.4*I)/(C*Vdc)
r=r*100              #in %
print "Ripple of the Filter r:",round(r,1),"%"

Ripple of the Filter r: 4.3 %

Example-15.6 Page Number-780

In [4]:
R=120.0                 #in ohm
C=10.0                  #Capacitance in microFarad
Rl=1000.0               #load Resistance in ohm
V=60.0                  #In volts(Dc voltage across filter initially)

#for an RC filter section:
#DC voltage across load(Rl) is Vdc=

Vdc=(Rl*V)/(R+Rl)
print "DC voltage across load(Rl) is Vdc=",round(Vdc,1),"V"

DC voltage across load(Rl) is Vdc= 53.6 V

Example-15.7 Page Number-781

In [12]:
#forthe given RC filter circuit:

#DC calculation:
R=500.0                 #in ohm
C=10*(10**-3)           #Capacitance in milliFarad
Rl=5000.0               #load Resistance in ohm
Vd=150.0                #In volts(Dc voltage across filter initially)
Vrms=15.0               #in volts(Ac voltage)
Vdc=(Rl*Vd)/(R+Rl)
print "DC component of voltage across load(Rl) is Vdc=",round(Vdc,1),"V"

#AC calculation:
#Capacitive Impedance Xc:
Xc=1.3/C                         #in ohm
#AC component of output voltage Vr:
Vr=(Xc*Vrms)/R
print "AC component of output voltage is Vr=",round(Vr,1),"V"

#Ripple of the output waveform r:
r=(Vr*100)/Vdc
print "Ripple of the output waveform r:",r,"%"

DC component of voltage across load(Rl) is Vdc= 136.4 V
AC component of output voltage is Vr= 3.9 V
Ripple of the output waveform r: 2.86 %

Example-15.8 Page Number-782

In [18]:
#from the given circuit diagram:
Vz=12                         #zener voltage in volts
Vbe=0.7                       #in volts(base-emitter voltage)
Vi=20.0                       #in volts(input supply)
Rl=1.0                        #in ohm(load resistance)
B=50.0                        #gain
R=220.0                       #resistace in ohm
#for the given regulator circuit:
Vo=Vz-Vbe                     #calculating Output voltage
Vce=Vi-Vo                     #calculating collector-emitter voltage
Ir=(Vi-Vz)/R                  #calculating current through resistance R
Ir=Ir*1000                    #calculating Ir in mA

#for the given resistance R:
Il=Vo/Rl                     #current through Rl
Ic=Il
Ib=Ic/B                      #base current
Iz=Ir-Ib                     #zener current


print " The output voltage Vo=",Vo,"V"
print "The zener current IZ=",round(Iz,1),"mA"

 The output voltage Vo= 11.3 V
The zener current IZ= 36.1 mA

Example-15.9 Page Number-783

In [20]:
#for the given circuit:
R1=20.0                       #resistace in Kohm
R2=30.0                       #resistace in Kohm
Vz=8.3                        #in volts(zener voltage)
V=0.7                         #in volts(base-emitter voltage)

#The regulated voltage Vo:
Vo=((R1+R2)*(Vz+V))/R2
print "The regulated voltage Vo:",Vo,"V"

The regulated voltage Vo: 15.0 V

Example-15.10 Page Number-784

In [21]:
#for the given circuit:
R1=30.0                      #resistace in Kohm
R=10.0                       #resistace in Kohm
Vz=6.2                       #in volts(zener voltage)
Vi=36                        #in volts(Input voltage)

#The regulated voltage Vo:
Vo=((1+(R1/R))*Vz)
print "The regulated voltage Vo:",Vo,"V"

The regulated voltage Vo: 24.8 V

Example-15.11 Page Number-786

In [26]:
#from  the given circuit:
Vz=8.2                       #in volts(zener voltage)
Vi=22                        #in volts(Input voltage)
Vbe=0.7                       #in volts(base-emitter voltage)
Rl=100.0                      #in ohm(load resistance)
Rs=120.0                      #in ohm(source resistance)

#THE load voltage Vl:
Vl=Vz+Vbe
print  "The regulated voltage Vl=",Vl,"V"

#the load current Il:
Il=(Vl/Rl)*1000
print  "The load current Il=",Il,"mA"

#the source current Is:
Is=((Vi-Vl)/Rs)*1000
print  "The source current Is=",round(Is,1),"mA"

#the collector current Ic:
Ic=(Is-Il)
print  "The collector current Ic=",round(Ic,1),"mA"

The regulated voltage Vl= 8.9 V
The load current Il= 89.0 mA
The source current Is= 109.2 mA
The collector current Ic= 20.2 mA

Example-15.13 Page Number-791

In [29]:
Vm=15            #in volts(output voltage)
C=250            #in microFarad
Idc=400          #in mA(current drawn by load)

#for the given transfomer:
Vr=(1.732*2.4*Idc)/C
Vdc=Vm-Vr      
Vi=Vdc-Vr             #minimum input voltage

print "The minimum input voltage Vi=",round(Vi,1),"V"

8.34912 6.65088
The minimum input voltage Vi= 1.69824 V

NOTE: The Solution given in the book is wrong because the value of Vdc substituted in the book is 15V

Example-15.14 Page Number-791

In [35]:
#to maintain regulation for the circuit:
#Vi>=7.3V
Vimin=7.3                #in volts (minimum vltage of input voltage Vi)
Vm=15                    #in volts(output voltage)
C=250                    #in microFarad
#maximum value of Vr:
Vr=Vm-Vimin

Vrms=Vr/(1.732)              #rms value of peak voltage

#Load current Idc:
Idc=(round(Vrms,1)*C)/2.4
print "The load current Idc=",round(Idc,1),"mA"

The load current Idc= 458.3 mA

Example-15.15 Page Number-792

In [45]:
#from the given circuit:
R1=240.0                     #resistace in ohm
R2=2400                      #resistace in ohm
Vref=1.25                    #in volts(Reference voltage)
Iadj=100*(10**-6)            #in ampere

#The regulated voltage Vo:
Vo=(Vref*(1+(R2/R1)))+(Iadj*R2)

print "The regulated voltage Vo:",Vo,"V"

The regulated voltage Vo: 13.99 V

Example-15.16 Page Number-792

In [47]:
#from the given circuit:
R2=1.8*(10**3)               #resistace in ohm
R1=240                       #resistace in ohm
Vref=1.25                    #in volts(Reference voltage)
Iadj=100*(10**-6)            #in ampere

#The regulated voltage Vo:
Vo=(Vref*(1+(R2/R1)))+(Iadj*R2)

print "The regulated voltage Vo:",round(Vo,2),"V"

The regulated voltage Vo: 10.8 V