How to find voltage in an open circuit

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Discussion Overview

The discussion revolves around determining the voltage in an open circuit, specifically in the context of a circuit diagram shared by a participant. The scope includes homework-related queries and the application of Thevenin and Norton equivalent circuits.

Discussion Character

  • Homework-related, Exploratory, Technical explanation

Main Points Raised

  • One participant seeks guidance on finding the voltage of an open circuit, mentioning previous experience with Thevenin and Norton equivalents.
  • Another participant questions the current flowing through resistors R2 and R3 in an open circuit and the voltage across them.
  • It is suggested that there is no current flowing through R2 and R3, leading to a zero voltage drop across these resistors.
  • A participant proposes using a voltage divider approach but expresses uncertainty about its applicability without at least two resistors connected.
  • A later reply asserts that if the voltage source is 5V, the open-circuit voltage (Voc) would also be 5V, but seeks confirmation of this assertion.
  • There is a clarification request regarding whether the statement about Voc being 5V is a question or a declaration.
  • One participant expresses confidence that the Voc would be 5V but seeks validation of their understanding.
  • A follow-up question is posed regarding the short-circuit current in relation to the open-circuit voltage.

Areas of Agreement / Disagreement

Participants express differing views on the application of the voltage divider and the implications of having an open circuit. While there is some agreement on the concept of Voc being equal to the voltage source, the discussion remains unresolved regarding the methodology and implications of the circuit configuration.

Contextual Notes

Participants have not fully resolved the assumptions regarding the circuit configuration and the definitions of open-circuit voltage and short-circuit current.

tooperoo
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Homework Statement



Hi guys, attached is a photo of the circuit. Apologies for the bad drawing, but paint is hard :P

What I am wondering is, how do you find the voltage of the open circuit with circuits like these? I have used Thevenin and Norton equivalent circuits before, but the circuits didn't look like this. Any guidance is appreciated! Thank you


Homework Equations





The Attempt at a Solution

 

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With an open circuit, how much current is flowing through R2 and R3 ? What is the voltage across them?
 
There isn't any at all, right?

What i usually do for the Voc is combine the resistors with a voltage divider and then multiply it by the voltage source. But u thought you need at least two resistors to do that approach.
 
You don't have a voltage divider in the circuit when the output is unconnected.

Look at it this way... If there is no current flowing through R2 and R3 the voltage drop across R2 and across R3 is zero. You can remove and replace R2 and R3 with wire.
 
So say if the voltage source was pumping out 5v, the Voc would be 5v?
 
tooperoo said:
So say if the voltage source was pumping out 5v, the Voc would be 5v?

Are you asking or telling?
 
Hahaha definitely asking. I'm nearly positive it would be 5v but I want to check if I'm correct.
 
tooperoo said:
Hahaha definitely asking. I'm nearly positive it would be 5v but I want to check if I'm correct.
That's the open-circuit voltage. Now what is the short-circuit current?
 

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