How Does Changing the Voltmeter Affect Potential Difference Readings?

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SUMMARY

This discussion focuses on how the type of voltmeter affects potential difference readings in electrical circuits. When using a digital voltmeter with infinite resistance, the potential difference is calculated as 3V and 5V for two different circuits. However, when a moving coil voltmeter with a resistance of 500 ohms is used, the readings change due to the voltmeter's impact on the circuit's total resistance. Participants emphasize the importance of applying Ohm's Law (V=IR) to derive accurate potential difference values.

PREREQUISITES
  • Understanding of Ohm's Law (V=IR)
  • Knowledge of potential dividers and their configurations
  • Familiarity with digital and moving coil voltmeters
  • Basic concepts of electrical resistance and conductance
NEXT STEPS
  • Calculate potential difference using different types of voltmeters
  • Explore the effects of voltmeter resistance on circuit performance
  • Learn about potential divider circuits and their applications
  • Investigate the principles of conductance in electrical circuits
USEFUL FOR

Students studying electrical engineering, educators teaching circuit analysis, and anyone interested in understanding the effects of measurement tools on electrical readings.

sallyishyper
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potential difference?

Homework Statement


picture shown in attachment

The sliders are at the mid-point of the potential dividers.
1. Find the potential difference recorded by a digital voltmeter of infinite resistance connected as the voltmeter V in each circuit.
250/2 = 125
6/250=0.024A and 100/2=50
0.024*125 =3V 10/100=0.1A
0.1*50 = 5V


2. The digital voltmeter is replaced by a moving coil voltmeter of resistance 500 ohms. Calculate the new readings when using this meter.


?
For this question I have tried to work out the conductance, then from this the total resistance and Ohms law to find the current. Then using Ohms law again try to find the potential difference, but I came out with an answer of minus 7.


Homework Equations


V=IR (i think)


The Attempt at a Solution


"
?
For this question I have tried to work out the conductance, then from this the total resistance and Ohms law to find the current. Then using Ohms law again try to find the potential difference, but I came out with an answer of minus 7."
 

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#1 looks good.

For #2, can you show your steps in coming up with your answer?
 

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