Guest

A galvanometer of resistance 20 ohm gives a full scale deflection when a current of 0.04A is passed through it. It is desired to convert it into an ammeter of full scale reading 20A. The only shunt availaible is 0.05 ohm resistance. The resistance that must be connected in series with the coil of galvanometer is?

A galvanometer of resistance 20 ohm gives a full scale deflection when a current of 0.04A is passed through it. It is desired to convert it into an ammeter of full scale reading 20A. The only shunt availaible is 0.05 ohm resistance. The resistance that must be connected in series with the coil of galvanometer is?

Grade:12

1 Answers

Ashish Kumar
askIITians Faculty 32 Points
10 years ago
The maximum current for full scale deflection of the galvanometer is 0.04 A.
To convert this to an ammeter the 20 A current will be distributed in the shunt and the galvanometer branch.
for full scale deflection, 0.04 = 0.05/ (20 + R + 0.05 ) 20 ( distribution of current in parallel combination )
R = 25 - 20.05 = 4.95 ohms


169-1800_signature1.GIF

Think You Can Provide A Better Answer ?

ASK QUESTION

Get your questions answered by the expert for free