Voltage in series and parallel circuits

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Discussion Overview

The discussion revolves around the behavior of voltage in series and parallel circuits, exploring why the voltage across components behaves differently in these configurations. The scope includes conceptual clarifications and technical explanations related to electrical circuits.

Discussion Character

  • Conceptual clarification
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants note that in a series circuit, the sum of the voltages across components equals the voltage supplied by the battery, while in parallel circuits, the voltages across different branches are equal.
  • One participant suggests that the voltage between any two points does not depend on the path taken, implying a fundamental property of voltage in parallel circuits.
  • Another participant expresses confusion over the original question, comparing it to asking why the voltage across a battery equals the voltage across the battery.
  • A participant questions why, in a parallel circuit with three branches, the voltage across each branch is not equal to one-third of the supplied voltage.
  • It is stated that the voltage across the battery remains constant regardless of the connections made to it, except in cases of a short circuit.
  • One participant explains that points connected to the same terminal of the battery must be at the same voltage potential, while the current through different resistors may vary due to differing resistance values.
  • Another participant mentions that in circuit diagrams, conductors are treated as perfect conductors with zero resistance, leading to constant voltage at any point on an idealized conductor.

Areas of Agreement / Disagreement

Participants express differing views on the implications of voltage in parallel circuits, with some confusion regarding the relationship between voltage and current in these configurations. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants have not fully clarified assumptions regarding the behavior of voltage in circuits, particularly in relation to the effects of resistance and current flow in parallel branches.

johnathon
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Why is it that in a series circuit the sum of the voltages across the components is equal to the voltage supplied by the battery but in parallel the voltages are equal for different branches in the circuit?
 
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hi johnathon! :smile:
johnathon said:
Why is it that … in parallel the voltages are equal for different branches in the circuit?

because the voltage between any two points does not depend on the path taken :wink:
 
johnathon said:
Why is it that in a series circuit the sum of the voltages across the components is equal to the voltage supplied by the battery but in parallel the voltages are equal for different branches in the circuit?

I must not be understanding your question because to me your question sounds exactly like "why is the voltage across a battery equal to the voltage across the battery"
 
phinds said:
I must not be understanding your question because to me your question sounds exactly like "why is the voltage across a battery equal to the voltage across the battery"

What I was asking is if there're three branches, why isn't the voltage across each branch equal to 1/3 of the supplied voltage?
 
johnathon said:
What I was asking is if there're three branches, why isn't the voltage across each branch equal to 1/3 of the supplied voltage?

Because the voltage across the battery is the voltage across the battery. What you hook up to it is irrelevant (other than a short circuit).
 
Hi johnathon

have a look at this circuit...

attachment.php?attachmentid=43390&stc=1&d=1328146169.gif


Q --what do you notice about points 1,2,3 and 4 ?

A -- They are all connected in common to the positive terminal of the battery
just as points 5,6,7 and 8 to the negative terminal
The fact that they are all commoned, means that they MUST be at the same voltage potential

Now with the current flowing in the circuit that's different. Because the resistors are of different values, the current flow through each resistor will be different
knowing the voltage across and the value of each resistor you can use Ohms Law and work out the current flowing through each resistance branch
and therefore the total current flowing in the circuit. The total current will be equal to the sum of the flow through each resistor.


cheers
Dave
 

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In circuit diagrams, conductors are treated as perfect conductors (zero resistance), so the voltage at any point on an idealized conductor is constant.
 

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