Internal resistance of an ammeter

In summary, the conversation discusses devising a non-destructive scheme to measure the resistance of a 0-1mA meter without using a multimeter as an ohmmeter. The solution involves using an external power supply and other circuit components, such as resistors, to ensure that no more than 1mA flows through the meter. The use of a current shunt and reading the voltage across the meter itself is suggested as a possible solution. The design and accuracy of this solution is also questioned.
  • #1
jmckennon
42
0

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?
 
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  • #2
Sorry, here is the design
 

Attachments

  • ammeter.bmp
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  • #3
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?
 
  • #4
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
 

1. What is internal resistance of an ammeter?

The internal resistance of an ammeter is the resistance within the ammeter itself, which affects the accuracy of the measurement. It is the resistance that the ammeter adds to the circuit when it is connected in series with the load.

2. Why is internal resistance important for an ammeter?

Internal resistance is important for an ammeter because it affects the flow of current through the circuit. If the internal resistance is too high, it can cause the reading on the ammeter to be inaccurate. It also affects the voltage drop across the ammeter, which can impact the overall circuit performance.

3. How does internal resistance affect the readings on an ammeter?

Internal resistance affects the readings on an ammeter by adding a small amount of resistance to the circuit, which can alter the flow of current. This can result in a lower reading on the ammeter than the actual current in the circuit.

4. Can internal resistance be reduced in an ammeter?

Yes, internal resistance can be reduced in an ammeter by using a larger wire size for the ammeter or by using a shunt resistor in parallel with the ammeter. This helps to decrease the overall resistance in the circuit and improve the accuracy of the ammeter readings.

5. How can I calculate the internal resistance of an ammeter?

The internal resistance of an ammeter can be calculated by measuring the voltage drop across the ammeter and the current in the circuit. Then, using Ohm's law (R=V/I), the internal resistance can be determined. Alternatively, the internal resistance may also be provided by the manufacturer of the ammeter.

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