# Chapter 27 Semiconductor devices¶

## Example 27.1 Page no 1446¶

In [3]:
#Given
E=1.5                   #V
Vd=0.5                      #V
P=0.1                     #W

#Calculation
Imax=P/Vd
V=E-Vd
R1=V/Imax

#Result
print"Value of resistance is",R1,"ohm"

Value of resistance is 5.0 ohm


## Example 27.2 Page no 1446¶

In [9]:
#Given
V=2                 #V
R=10.0           #ohm
R1=20.0

#Calculation
I=V/R
I1=V/R1

#Result
print"(i) Current drawn from battery is", I,"A"
print"(ii) Current drawn from point B is",I1,"A"

(i) Current drawn from battery is 0.2 A
(ii) Current drawn from point B is 0.1 A


## Example 27.3 Page no 1446¶

In [27]:
#given
Vl=15                #V
Rl=2.0*10**3
Iz=10                   #mA

#Calculation
Il=(Vl/Rl)*10**3
Ir=Iz+Il
Vr=Ir*10**-2*R1
V=Vr+Vl

#Result
print"Voltage is", V,"V"
print"Zener rating required is",Ir,"mA"

Voltage is 18.5 V
Zener rating required is 17.5 mA


## Example 27.4 Page no 1447¶

In [36]:
#Given
N=10.0
V=230                    #V

#Calculation
import math
Vrpm=math.sqrt(2)*V
Vsm=Vrpm/N
Vdc=Vsm/math.pi

#Result
print"(i) The output dc voltage is", round(Vdc,2),"V"
print"(ii) Peak inverse voltage is",round(Vsm,2),"V"

(i) The output dc voltage is 10.35 V
(ii) Peak inverse voltage is 32.53 V


## Example 27.5 Page no 1447¶

In [67]:
#Given
Vm=50                            #V
rf=20.0
Rl=800                               #ohm

#Calculation
import math
Im=(Vm/(rf+Rl))*10**3
Idc=Im/math.pi
Irms=Im/2.0
P=(Irms/1000.0)**2*(rf+Rl)
P1=(Idc/1000.0)**2*Rl
V=Idc*Rl*10**-3
A=P1*100/P

#Result
print"(i) Im=",round(Im,0),"mA \nIdc=",round(Idc,1),"mA \nIrms=",round(Irms,1),"mA"
print"(ii) a.c power input is",round(P,3),"watt \nd.c. power is",round(P1,3),"watt"
print "(iii) d.c. output voltage is",round(V,2),"Volts"
print"(iv) Efficiency of rectification is", round(A,1),"%"

(i) Im= 61.0 mA
Idc= 19.4 mA
Irms= 30.5 mA
(ii) a.c power input is 0.762 watt
d.c. power is 0.301 watt
(iii) d.c. output voltage is 15.53 Volts
(iv) Efficiency of rectification is 39.5 %


## Example 27.6 Page no 1448¶

In [85]:
#Given
rf=20                            #ohm
Rl=980
V=50                               #v

#Calculation
import math
Vm=V*math.sqrt(2)
Im=(Vm/(rf+Rl))*10**3
Idc=(2*Im)/(math.pi)
Irms=Im/math.sqrt(2)

#Result
print"(iii) R.M.S value of load current is",Irms,"mA"

(i) load current is 70.7 mA
(ii) Mean load currant is 45.0 mA
(iii) R.M.S value of load current is 50.0 mA


## Example 27.7 page no 1448¶

In [122]:
#Given
N=5.0
A=230                   #V
B=2
Rl=100

#Calculation
import math
V1=A/N
V2=V1*math.sqrt(2)
Vm=V2/B
Idc=2*Vm/(math.pi*Rl)
Vdc=Idc*Rl

#Result
print"(i) d.c voltage output is",round(Vdc,1),"V"
print"(ii) peak inverse voltage is",round(V2,0),"V"

(i) d.c voltage output is 20.7 V
(ii) peak inverse voltage is 65.0 V


## Example 27.8 page no 1448¶

In [123]:
#Given
Il=4.0              #mA
Vz=6                #V
E=10.0              #V

#Calculation
Lz=5*Il
L=Il+Lz
Rs=E-Vz
Rs1=Rs/(L*10**-3)

#Result
print"The value of series resister Rs",round(Rs1,0),"ohm"

The value of series resister Rs 167.0 ohm


## Example 27.9 page no 1449¶

In [139]:
#Given
Vf=0.3            #V
If=4.3*10**-3     #A
Vc=0.35
Va=0.25
Ic=6*10**-3
Ia=3*10**-3

#Calculation
Rdc=Vf/If
Vf1=Vc-Va
If1=Ic-Ia
Rac=Vf1/If1

#Result
print"(i) D.C. resistance is",round(Rdc,2),"ohm"
print"(ii) A.C. resistance is",round(Rac,2),"ohm"

(i) D.C. resistance is 69.77 ohm
(ii) A.C. resistance is 33.33 ohm


## Example 27.10 page no 1462¶

In [144]:
#Given
A=0.9
Ie=1          #mA

#Calculation
Ic=A*Ie
Ib=Ie-Ic

#Result
print"Base current is",Ib,"mA"

Base current is 0.1 mA


## Example 27.11 page no 1462¶

In [147]:
#Given
B=50
Ib=0.02       #mA

#Calculation
Ic=B*Ib
Ie=Ib+Ic

#Result
print"Ie =",Ie,"mA"

Ie = 1.02 mA


## Example 27.12 page no 1462¶

In [165]:
#Given
B=49
Ie=12          #mA
Ib=240         #microA

#Calculation
A=(B/1+B)*10**-2
Ic=A*Ie
Ic1=B*Ib

#Result
print" The value of Ic using A is",Ic,"mA"
print" The value of Ic using B is",Ic1*10**-3,"mA"

 The value of Ic using A is 11.76 mA
The value of Ic using B is 11.76 mA


## Example 27.13 page no 1463¶

In [169]:
#Given
B=45.0
Ic=1       #V

#Calculation
Ib=Ic/B

#Result
print" The base current for common emitter connection is",round(Ib,3),"mA"

 The base current for common emitter connection is 0.022 mA


## Example 27.14 page no 1463¶

In [184]:
#Given
Vcc=8               #V
V=0.5               #V
Rc=800.0            #ohm
a=0.96

#Calculation
Vce=Vcc-V
Ic=V/Rc*10**3
B=a/(1-a)
Ib=Ic/B

#Result
print"(i) Collector-emitter voltage is",Vce,"V"
print"(ii) Base current is",round(Ib,3),"mA"

(i) Collector-emitter voltage is 7.5 V
(ii) Base current is 0.026 mA


## Example 27.15 page no 1463¶

In [188]:
#Given
a=10
b=2
c=3

#Calculation
Vce=a-b
Ic=c-b
Ro=Vce/Ic

#Result
print"The output resistance is",Ro,"k ohm"

The output resistance is 8 k ohm


## Example 27.16 page no 1464¶

In [249]:
#Given
Ic=4.0        #mA
Ib=30         #micro A
Ib1=20        #micro A
Vce=10        #V
c=4.5         #mA
d=3.0         #mA

#Calculation
Ib2=Ib-Ib1
Ic1=c-d
Bac=Ic1/Ib2*10**3
Bdc=c/Ib*10**3

#Result
print"The value of Bac of the transister is",Bdc
print"The value of Bdc of the transister is",Bdc

The value of Bac of the transister is 150.0
The value of Bdc of the transister is 150.0


## Example 27.17 page no 1464¶

In [240]:
#Given
Ri=665.0        #ohm
Ib=15.0         #micro A
Ic=2            #mA
Ro=5*10**3      #ohm

#Calculation
Bac=Ic/Ib*10**3
Av=Bac*(Ro/Ri)

#Result
print" The voltage gain is", round(Av,0)

 The voltage gain is 1003.0


## Example 27.18 page no 1464¶

In [236]:
#Given
Vbb=2.0                            #v
Rc=2000                           #ohm
B=100
Vbe=0.6                            #V

#Calculation
Ic=Vbb/Rc*10**3
Ib=Ic/B
Ib1=10*Ib
Rb=(Vbb-Vbe)/Ib
Ic=B*Ib1

#Result
print"d.c. collector current is",Ic,"mA"

d.c. collector current is 10.0 mA


## Example 27.19 page no 1465¶

In [257]:
#Given
N=10**10
e=1.6*10**-19
t=10**-6

#Calculation
Ie=(N*e)/t*10**3
Ib=(2/100.0)*Ie
Ic=Ie-Ib
c=Ic/Ie
B=Ic/Ib
#Result
print"The current transfer ratio",c
print"current amplification factor is",B

The current transfer ratio 0.98
current amplification factor is 49.0


## Example 27.20 page no 1465¶

In [279]:
#Given
a=200
b=50
c=17
d=5
e=4000

#Calculation
Ib=(a-b)*10**-3
Ic=c-d
B=Ic/Ib
D=e/B
Ap=B**2*D

#Result
print" The value of current gain is",B
print" The value of resistance gain is",D
print" The value of power gain is",Ap*10**-5,"*10**5"

 The value of current gain is 80.0
The value of resistance gain is 50.0
The value of power gain is 3.2 *10**5


## Example 27.21 page no 1469¶

In [294]:
#Given
L1=58.6*10**-6                  #H
C1=300.0*10**-12                  #F

#Calculation
import math
f=1/((2.0*math.pi)*math.sqrt(L1*C1))

#Result
print"Frequency of oscillation is", round(f*10**-3,0),"KHz"

Frequency of oscillation is 1200.0 KHz


## Example 27.22 Page no 1469¶

In [309]:
#Given
Vbe=0.8                   #V
Vcc=5                       #V
Rc=1                        #K ohm
b=250.0
Rb=100                      #K ohm

#Calculation
Ic=Vcc/Rc
Ib=(Ic/b)*10**3
Vi=(Ib*Rb)+Vbe

#Result
print"(i) The minimum base current is",Ib,"micro A"
print"(ii) The input voltage is",round(Vi*10**-3,0),"V"
print"(iii) Between 0 V and 0.6 V,the transistor will switched off. Between 2.8 V and 5.0 V the transistor will switched on"

(i) The minimum base current is 20.0 micro A
(ii) The input voltage is 2.0 V
(iii) Between 0 V and 0.6 V,the transistor will switched off. Between 2.8 V and 5.0 V the transistor will switched on