Internal resistance of an ammeter

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Discussion Overview

The discussion revolves around devising a non-destructive method to measure the internal resistance of a 0-1mA ammeter in a laboratory setting. Participants explore circuit design options using external power supplies and resistors while ensuring that the current does not exceed 1 mA.

Discussion Character

  • Homework-related, Exploratory, Technical explanation

Main Points Raised

  • One participant reports using a simulation to determine the internal resistance as 1 micro ohm but expresses uncertainty about the accuracy of this value based on the voltmeter and ammeter readings.
  • Another participant questions the feasibility of reading voltage across a current shunt and the ammeter itself as an alternative method for measuring resistance.
  • A later reply indicates confusion regarding the setup of the circuit needed to read voltage from both the current shunt and the ammeter, seeking clarification on how to implement this approach.

Areas of Agreement / Disagreement

Participants do not appear to reach a consensus on the best method for measuring the internal resistance, with some exploring simulation results while others suggest alternative measurement techniques. The discussion remains unresolved regarding the optimal circuit design.

Contextual Notes

Participants express uncertainty about the setup and interpretation of measurements, indicating potential limitations in understanding the circuit design and measurement techniques required for this task.

jmckennon
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Homework Statement


Devise a NON DESTRUCTIVE scheme to measure the resistance of the 0-1mA meter that is provided in the lab. You may make use of an external power supply (or battery) and other circuit components such as resistors to make your measurement. Design your measurement scheme so that no more than 1 mA will flow through the meter! You can not use the multimeter as an ohmmeter to make this measurement!

Homework Equations



v=ir

The Attempt at a Solution



I used a multisim simulation for the circuit. I ended up getting the internal resistance to be 1 micro ohm but I am not sure if that is correct, as i used the values provided by the voltmeter and ammeter in the circuit.

https://email.umassd.edu/src/download.php?startMessage=1&passed_id=2201&mailbox=INBOX&ent_id=2&passed_ent_id=0



here is our design.

Is this done correctly?
 
Last edited by a moderator:
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Sorry, here is the design
 

Attachments

I can't see your attachment yet (waiting approval). But why can't you just read the voltage off a current shunt and across the current meter itself?
 
I guess the wording of the question is getting pretty jumbled in my head. what would that circuit look like? I'm not exactly sure how to read or set up that up. How would i set up is up so i can read the voltage off a current shunt and across the meter itself? I'm just hella confused here
 

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