Understanding Voltage: A Question on Voltage

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Discussion Overview

The discussion centers around the concept of voltage, specifically the meanings of -VR and +VR in a given diagram. Participants explore the implications of voltage polarity in relation to current flow, with a focus on understanding the context of the diagram presented.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant expresses confusion about the meanings of -VR and +VR in the context of the diagram, questioning whether point A is supposed to be more positive than point B.
  • Another participant suggests that A will be more positive than B if the current enters at A, indicating that the sign of Vr depends on the direction of current flow depicted in the picture.
  • A participant notes the need for more context regarding the diagram, proposing that it could illustrate differences between electron and conventional current flow or the behavior of power sources.
  • Another participant clarifies that the diagram shows voltage polarities between resistors and power sources, explaining that the current flow direction affects the voltage drop across the resistor.
  • One participant reiterates the need for context, expressing confusion about the arrows with V and its sign, and cites a source for further reference.

Areas of Agreement / Disagreement

Participants express varying levels of understanding and confusion regarding the diagram, with no consensus reached on its interpretation or the implications of the voltage signs.

Contextual Notes

The discussion lacks specific context for the diagram being referenced, which may lead to differing interpretations of the voltage signs and their meanings.

machinarium
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attachment.php?attachmentid=33516&stc=1&d=1301071429.png


This is what I didn't understand about the picture.
About the -VR and +VR, why do we have them, in both directions. I don't understand what they mean. Was A supposed to be more positive than B?

I think I understand voltage and current but I haven't gained insight. That make me confused about this.
 

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A will be more positive than B if current enters at A i.e, when Ir is positive
The sign of Vr depends on direction of current flow which is depicted in the picture.
 
Without a bit more context for the picture it's kind of hard to know what it's for. Is this from a textbook or some webpage?

It could be showing the difference between electron and conventional current flow, or that power is still positive if you switch the voltage, or maybe something else I can't think of yet.
 
It is showing the difference in voltage polarities between resistors and power sources.

Just looking at the red writing in the diagram at left, the current is flowing downwards and producing a voltage drop across the resistor with the positive voltage being at the point where the current enters the resistor.

If the polarity was as shown in the blue writing (ie -VR) then the object is a battery or other power source.

It seems to add more confusion than it needs to.
 
Jiggy-Ninja said:
Without a bit more context for the picture it's kind of hard to know what it's for. Is this from a textbook or some webpage?

It could be showing the difference between electron and conventional current flow, or that power is still positive if you switch the voltage, or maybe something else I can't think of yet.

Im sorry about the source. en.wikiversity.org/wiki/Passive_sign_convention
Im confused of the arrows with V and its sign.
 

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