Troubleshooting Voltmeter Reading w/ Resistance 5*10^4

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Homework Help Overview

The discussion revolves around a voltmeter reading in an electrical circuit, specifically focusing on the impact of the voltmeter's resistance of 5*10^4 Ohms when connected between point b and ground. Participants are exploring concepts related to voltage measurement and circuit behavior.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to apply a formula for voltmeter readings but encounters discrepancies in their calculations. Other participants suggest considering the effect of the voltmeter's resistance in parallel with another resistor to find a new voltage ratio.

Discussion Status

The discussion is ongoing, with some participants providing insights into the relationship between the voltmeter and circuit resistances. There is a lack of explicit consensus, but a potential direction involving equivalent resistance calculations has been introduced.

Contextual Notes

Participants are grappling with the implications of the voltmeter's presence in the circuit and how it affects voltage readings, indicating a need for clarification on circuit analysis principles.

joshanders_84
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This is another problem I am having troubles with. Here's the prompt:

What is the reading of a voltmeter with the proper range and with resistance 5*10^4 Ohms when connected between point b and ground?

I know that for voltmeters, V = I_fs (R_c + R_s), and I tried solving for V using the I through the system as I_fs, which I solved as (400V/300000) = .001333, and then using 5*10^4 and 200000 as the resistors, but it says my answer is off by an additive constant. I don't understand what I am dong wrong...all help is appreciated. Thanks
Josh
 

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If the voltmeter wasn't there, or was perfect, then the voltage at b would be 2/3 of that at a.

Now when the voltmeter is present, its resistance is in parallel with the 200k-ohm resistor, so you can calculate the equivalent resistance of the parallel combination, and get a new ratio for the voltages at a and b.
 
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I don't understand how that helps...sorry. I just don't get what I am doing wrong still, or how the above would help me go further...
 
o i ci I got it now, thank you
 

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