Browse by Stream
QnA
Home
QnA
Go To Your Study Dashboard

Get Answers to all your Questions

header-bg qa
  • Home
  • NCERT
  • A multirange current meter can be constructed by using a galvanometer circuit as shown in figure. We want a current meter that can measure 10 mA, 100 mA and 1 mA using a galvanometer of resistance 10

A multirange current meter can be constructed by using a galvanometer circuit as shown in the figure. We want a current meter that can measure 10 mA, 100 mA and 1 mA using a galvanometer of resistance 10 \Omegaand that produces maximum deflection for a current of 1 mA. Find S_{1}. S_{2}and S_{3} that have to be used.

Answers (1)

A galvanometer can be converted into an ammeter by connecting a very low resistance wire (shunt resistance) connected in parallel with a galvanometer to extend its range. iGg=(I−Ig)s

Where iG is the range of the galvanometer, G is the resistance of the galvanometer.

For i1=10 mA

S1+S2+S3 are in series as a shunt resistance

So,

iGg=(i1−iG)S

1×10=(10−1)(S1+S2+S3)..(i)

For i2=100 mA

S2+S3 are in series as a shunt resistance

So,

iG(G+S1)=(i2−iG)(S2+S3)

1×(10+S1)=(100−1)(S2+S3)...(ii)

For i3=1000 mA

S3 acts as a shunt resistance.

So,

iG(G+S1+S2)=(i3−iG)S3

1×(10+S1+S2)=(1000−1)S3...(i)

From(i),(ii) and (iii)

S1=1Ω

S2=0.1Ω

S3=0.01Ω

 

Posted by

infoexpert24

View full answer

Similar Questions

Latest Question