How to Calculate Shunt Resistance for Converting a Galvanometer to an Ammeter?

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Homework Help Overview

The discussion revolves around calculating the shunt resistance required to convert a galvanometer into an ammeter, specifically addressing a galvanometer with a full scale current of 0.100 mA and a coil resistance of 50 ohms, aiming for a full scale ammeter reading of 60 mA.

Discussion Character

  • Exploratory, Mathematical reasoning, Assumption checking

Approaches and Questions Raised

  • Participants discuss the relationship between the galvanometer's full scale current and the desired ammeter range, questioning the relevant equations needed for the calculation. There is also a request for clarification on the approach to finding the shunt resistance.

Discussion Status

Some participants have offered guidance on the relevant equations and expressed uncertainty about the calculations. There is a mix of attempts to derive the shunt resistance, with some participants seeking confirmation of their results.

Contextual Notes

Participants note the challenge of finding similar examples online and the original poster expresses confusion about the problem setup. There is an emphasis on ensuring the correct current distribution between the galvanometer and the shunt resistance.

dgresch
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A galvanometer has a full scale current of 0.100 mA and a coil resistance of 50ohmes. In constructing an ammeter of 60mA full scale, what shunt resistnace is needed?I'm lost on this one.
 
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This is a common problem type. Try searching the forum for similar examples. In fact, take a look at the bottom of this window under the "Similar Threads" header.
 
dgresch said:
A galvanometer has a full scale current of 0.100 mA and a coil resistance of 50ohmes. In constructing an ammeter of 60mA full scale, what shunt resistnace is needed?


I'm lost on this one.

You want 0.1mA to go through the 50 Ohm coil, and the rest of the 60mA to go through the low-resistance shunt in parallel with the coil. What do you think the Relevant Equations are?
 
Thanks gneill, I'm new to this and I thought to just post my own thread since I didn't see it on google :P.
 
is the answer 0.083ohm
 
rohans said:
is the answer 0.083ohm

It might be :smile: Can you show your work?
 
s=(Ig/(I-Ig))*R
s-required shunt
R-resistance of galvanometer(50)
Ig-full scale deflection current of the galvanometer(0.1)
I-desired current range(60)
just substitute the given data
 

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