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“Conversion of a Galvanometer into an Ammeter-Numerical”

TABLE OF CONTENTS:

NUMERICAL BASED ON GALVANOMETER

Galvanometer is an instrument which is used to detect and measure small electric current in an electrical circuit.These galvanometers are used in the meter bridges and potentiometers where they indicate the null deflection or zero current .The galvanometer can be converted into an ammeter or voltmeter.Here, the numericals based on conversion of galvanometer into an ammeter is discussed.

Moving coil galvanometer demonstration

CONVERSION OF A GALVANOMETER INTO AN AMMETER: NUMERICAL

Conversion of a galvanometer into an ammeter

NUMERICAL:

NUMERICAL-1

<img src="galvanometer-ammeter.jpg" alt="Image showing the numerical on conversion of galvanometer into ammeter">
Conversion of galvanometer into ammeter-Numerical

SOLUTION:

<img src="galvanometer-ammeter.jpg" alt="Image showing the numerical on the conversion of galvanometer into ammeter">
Conversion of galvanometer into ammeter- Numerical

CONVERSION OF A GALVANOMETER INTO AN AMMETER:

<img src="galvanometer-ammeter.jpg" alt="Image showing the expression and formula for the  conversion of galvanometer into an ammeter">
Conversion of galvanometer into ammeter

SHUNT :

A resistor with a very low resistance connected in parallel with other resistor.Such type of resistor is called shunt resistance.It is made up of a material havingย  low temperatureย  coefficient of resistance.

SHUNT RESISTANCE

Conversion of galvanometer into ammeter-Shunt resistance

Numericalย  On Conversion of Galvanometer into an Ammeter-1

Conversion of galvanometer into an ammeter-numerical

Numericalย  On Conversion of Galvanometer into an Ammeter-2

Conversion of galvanometer into an ammeter-Numerical (2)

Numericalย  On Conversion of Galvanometer into voltmeter

ย 
Conversion of galvanometer into voltmeter-Numerical

Numericalย  On Conversion of Galvanometer into an Ammeter-4

ย 
Conversion of galvanometer into ammeter -numerical

 

CONVERSION OF GALVANOMETER INTO AMMETER-PRACTICE PROBLEMS

Problem number

Galvanometerย  ย  ย  ย  ย  ย  ย  ย  ย  ย  ย  ย  ย  ย  resistance (G)

Full-scale deflection current (Ig)

Desired ammeter range ย  ย  ย  ย  (I)

Shunt resistanceย  ย  ย  ย  ย  ย  ย  (S)

ย  ย  ย  ย  ย  1

ย  ย  ย  ย  ย  ย  ย  ย  ย  50 ฮฉ

ย  ย  ย  ย  1 mA

ย  ย  ย  ย  ย  ย  ย 10 A

ย  ย  ย  ย  ย  ย  ย  ?

ย  ย  ย  ย  ย  2

ย  ย  ย  ย  ย  ย  ย  ย  100 ฮฉ

ย  ย  ย  500 ฮผA

ย  ย  ย  ย  ย  ย  ย  5 A

ย  ย  ย  ย  ย  ย  ย  ?

ย  ย  ย  ย  ย  3

ย  ย  ย  ย  ย  ย  ย  ย  ย  25 ฮฉ

ย  ย  ย  ย  ย 2 mA

ย  ย  ย  ย  ย  ย  ย  1 A

ย  ย  ย  ย  ย  ย  ย  ?

ย  ย  ย  ย  ย  4

ย  ย  ย  ย  ย  ย  ย  ย  ย  75 ฮฉ

ย  ย  ย  ย  1 mA

ย  ย  ย  ย  ย 20 A

ย  ย  ย  ย  ย  ย  ย  ย ?

ย  ย  ย  ย  ย  5

ย  ย  ย  ย  ย  ย  ย  ย  ย 60 ฮฉ

ย  ย  ย  300 ฮผA

ย  ย  ย  ย  ย 2 A

ย  ย  ย  ย  ย  ย  ย  ย ?

ย  ย  ย  ย  ย  6

ย  ย  ย  ย  ย  ย  ย  120 ฮฉ

ย  ย  ย  ย 200 ฮผA

ย  ย  ย  ย  10 A

ย  ย  ย  ย  ย  ย  ย  ?ย ย ย ย ย ย ย 

ย  ย  ย  ย  ย  7

ย  ย  ย  ย  ย  ย  ย  ย  30 ฮฉ

ย  ย  ย  ย 1.5 mA

ย  ย  ย  ย  ย 5 A

ย  ย  ย  ย  ย  ย  ย  ?

ย  ย  ย  ย  ย  8

ย  ย  ย  ย  ย  ย  ย  ย  90 ฮฉ

ย  ย  ย  ย 400 ฮผA

ย  ย  ย  ย 15 A

ย  ย  ย  ย  ย  ย  ย  ย ?

ย  ย  ย  ย  ย 9

ย  ย  ย  ย  ย  ย  ย  ย 50 ฮฉ

ย  ย  ย  1 mA

ย  ย  ย 50 A

ย ย ย ย ย ย 

ย  ย  ย  ย  ย  ย  ย  ย ?

ย  ย  ย  ย  10

ย  ย  ย  ย  ย  ย  ย 200 ฮฉ

ย  ย  ย 100 ฮผA

ย  ย  ย  ย 1 A

ย  ย  ย  ย  ย  ย  ย  ย ?

Solution for the above numerical Problems

Problem Number

ย  ย  ย  Solution

Problem Number

ย  ย  ย  Solution

ย  ย  ย  1

ย  ย  ย  ย  ย  0.005ฮฉ

ย  ย  ย  ย  ย  ย  6

ย  ย  ย  ย  0.0024ฮฉ

ย  ย  ย  2

ย  ย  ย  ย  ย  0.01ฮฉ

ย  ย  ย  ย  ย  ย  7

ย  ย  ย  ย  ย  0.009ฮฉ

ย  ย  ย  3

ย  ย  ย  ย  ย  0.0501ฮฉ

ย  ย  ย  ย  ย  ย  8

ย  ย  ย  ย  ย  ย  ย  ย  ย  ย  ย  0.0024ฮฉ

ย  ย  ย  4

ย  ย  ย  ย  ย  ย  ย  ย  ย  ย 0.00375ฮฉ

ย  ย  ย  ย  ย  ย  9

ย  ย  ย  ย  ย  0.001ฮฉ

ย  ย  ย  5

ย  ย  ย  ย  ย  0.009ฮฉ

ย  ย  ย  ย  ย  10

ย  ย  ย  ย  ย  0.02ฮฉ

Question 11:

A galvanometer coil has a resistance of 15 ฮฉ, and the metre shows full-scale deflection for a current of 4 mA. How will you convert the metre into an ammeter of range 0 to 6 A?

Answer:

A shunt resistor of ย must be connected in parallel with the galvanometer.

Question 12:

A galvanometer coil has a resistance of 12 ฮฉ, and the metre shows full-scale deflection for a current of 3 mA. How will you convert the metre into a voltmeter of range 0 to 18 V?

Answer:

A resistor of R=5988 ohms must be connected in series with the galvanometer.

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