Chapter 3 Ammeters

Example 3.1 (a) Page no 65

In [4]:
#Given
R=100                               #ohm
Im=1*10**-3                          #A
I=100*10**-3

#Calculation
Rsh=Im*R/(I-Im)

#Result
print"The value of shunt resistance is ", round(Rsh,2),"ohm"

The value of shunt resistance is  1.01 ohm

Example 3.1 (b) Page no 65

In [9]:
#Given
Im=100.0*10**-6                         #A
Rm=500                                  #ohm
I=100*10**-3                            #A

#calculation
n=I/Im
Rsh=Rm/(n-1)

#Result
print"The value of required shunt is ", round(Rsh,2),"ohm"

The value of required shunt is  0.5 ohm

Example 3.2 Page no 66

In [17]:
#Given
I=10.0*10**-3                             #A
Im=1.0*10**-3                             #A
Rm=100                                    #ohm
I1=20.0*10**-3
I2=50.0*10**-3

#Calculation
# For the range of 0-10 mA
Rsh1=(Im*Rm)/(I-Im) 

# For the range of 0-20 mA
Rsh2=(Im*Rm)/(I1-Im) 

# For the range of 0-50 mA
Rsh3=(Im*Rm)/(I2-Im)

#Result
print"The value of the shunt resistance required for the range 0-10 mA", round(Rsh1,2),"ohm"
print"The value of the shunt resistance required for the range 0-20 mA", round(Rsh2,1),"ohm"
print"The value of the shunt resistance required for the range 0-50 mA", round(Rsh3,3),"ohm"

The value of the shunt resistance required for the range 0-10 mA 11.11 ohm
The value of the shunt resistance required for the range 0-20 mA 5.3 ohm
The value of the shunt resistance required for the range 0-50 mA 2.041 ohm

Example 3.3 page no 67

In [22]:
#Given
Im=10.0*10**-3                          #A
Rm=500                                  #ohm
I=1000.0*10**-3                         #A
I1=5000.0*10**-3                        #A
I2=10000.0*10**-3                       #A

#Calculation
# For the range of 0-1A, i.e, 1000mA
Rsh1=(Im*Rm)/(I-Im)  

# For the range of 0-5A, i.e, 5000mA
Rsh2=(Im*Rm)/(I1-Im) 

# For the range of 0-10A, i.e, 10000mA
Rsh3=(Im*Rm)/(I2-Im)

#Result
print"The value of shunt resistance for the range 0-1A", round(Rsh1,2),"ohm"
print"The value of shunt resistance for the range 0-5A", round(Rsh2,3),"ohm"
print"The value of shunt resistance for the range 0-10A", round(Rsh3*10**-1,3),"ohm"

The value of shunt resistance for the range 0-1A 5.05 ohm
The value of shunt resistance for the range 0-5A 1.002 ohm
The value of shunt resistance for the range 0-10A 0.05 ohm