Question on voltage in a Thevenin equivalent circuit

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Discussion Overview

The discussion revolves around understanding voltage relationships in a Thevenin equivalent circuit, specifically focusing on the voltage across a resistor and the implications of circuit configuration on voltage equality. The scope includes conceptual clarification and technical explanation related to basic electricity principles.

Discussion Character

  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • One participant questions whether the voltage across a 6 ohm resistor (V1) is equal to the open-circuit voltage (VOC).
  • Another participant confirms that V1 is indeed equal to VOC, noting that there is no potential drop across a 5 ohm resistor when the terminals are open.
  • A participant inquires why the voltage across the voltage source (V2) is not equal to V1 and VOC, suggesting a misunderstanding of parallel circuits.
  • Responses clarify that V2 is not equal to V1 and VOC because the components between their leads prevent them from being in parallel.
  • Further clarification is provided that for two components to be considered in parallel, they must share two nodes.

Areas of Agreement / Disagreement

Participants generally agree on the relationships between the voltages and the conditions for components to be in parallel, but there is an ongoing exploration of the concepts without a definitive conclusion on the broader implications.

Contextual Notes

Participants express uncertainty regarding the definitions and conditions that determine parallel configurations, which may affect their understanding of voltage relationships in the circuit.

influx
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thevneogo.png


I am trying to refresh my basic electricity knowledge so the questions might be a little stupid lol.

1) Am I correct in saying that the voltage, V1, across the 6 ohm resistor is equal to the VOC?

2) Why isn't the voltage across the voltage source, V2, equal to V1 and VOC? I thought that the voltages in a parallel circuit are equal?


Cheers!
 
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influx said:
thevneogo.png


I am trying to refresh my basic electricity knowledge so the questions might be a little stupid lol.

1) Am I correct in saying that the voltage, V1, across the 6 ohm resistor is equal to the VOC?
Yes. There's no potential drop across the 5 Ω resistor when terminals a-b are open as shown.

2) Why isn't the voltage across the voltage source, V2, equal to V1 and VOC? I thought that the voltages in a parallel circuit are equal?
They are not in parallel. There are components in between their respective leads. In particular, the 3 Ω resistor and the controlled voltage source separate the 10 V supply and the 6 Ω resistor's upper leads.
 
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gneill said:
Yes. There's no potential drop across the 5 Ω resistor when terminals a-b are open as shown.


They are not in parallel. There are components in between their respective leads. In particular, the 3 Ω resistor and the controlled voltage source separate the 10 V supply and the 6 Ω resistor's upper leads.

So if there are components between the wire connecting two elements, the two elements are not in parallel?

Thanks
 
influx said:
So if there are components between the wire connecting two elements, the two elements are not in parallel?

Thanks

Correct. For two components to be in parallel they must share two nodes.
 

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