How Does Wire Length Affect Voltage in an Electrical Circuit?

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SUMMARY

The discussion focuses on the relationship between wire length and voltage in electrical circuits, specifically noting that as wire length increases from 10 cm to 100 cm, the voltmeter reading increases by approximately 0.1 V. This phenomenon is attributed to the internal resistance of the power supply, which affects voltage measurements. The conversation emphasizes the importance of considering the power pack's internal resistance, particularly when analyzing voltage and current changes in relation to wire length.

PREREQUISITES
  • Understanding of Ohm's Law and its application in electrical circuits
  • Familiarity with the concept of internal resistance in power supplies
  • Knowledge of how to use a voltmeter for measuring voltage across components
  • Basic principles of electrical resistance and its impact on current flow
NEXT STEPS
  • Investigate the effects of internal resistance on circuit performance
  • Learn about constant current sources and their characteristics
  • Explore the relationship between voltage, current, and resistance using circuit simulation tools
  • Examine real-world applications of wire length in electrical installations and their impact on performance
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Students studying electrical engineering, educators teaching circuit theory, and hobbyists interested in practical electronics experiments.

polekitten
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Homework Statement


We conducted an investigation into wire length, current and resistance but kept track of the voltage rather than relying on the power pack setting. We noticed the voltmeter (measuring across the power pack) reading increased as the length of the wire increased though by only about 0.1 V from 10-100 cm lengths.

Homework Equations

The Attempt at a Solution


Is this something to do with internal resistance and energy being lost due to the higher resistance?
 
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polekitten said:

Homework Statement


We conducted an investigation into wire length, current and resistance but kept track of the voltage rather than relying on the power pack setting. We noticed the voltmeter (measuring across the power pack) reading increased as the length of the wire increased though by only about 0.1 V from 10-100 cm lengths.

Homework Equations

The Attempt at a Solution


Is this something to do with internal resistance and energy being lost due to the higher resistance?
You have suggested internal resistance. What would happen to our voltmeter readings during the experiment if the power supply had a small internal resistance, such as 1 Ohm? Say the current changes from 0.1 amp to 1 amp as the wire is shortened.
 
You have not defined the power pack electrically. The easiest assumption would be that is is a source of constant current, in which case the relation between V and R should be obvious.

If the power pack has finite (as opposed to infinite) source resistance then that resistance has to be included in your computations of R, given V.
 

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