Need help in step response circuit diagram

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Discussion Overview

The discussion revolves around the analysis of a circuit diagram related to step response, particularly focusing on the transformation to the s domain after a switch changes position. Participants are exploring concepts related to circuit behavior at the moment the switch is activated and the implications for voltage across components.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the inclusion of a 10/s term in the s domain transformation, suggesting that since the switch has moved to position b, the 10V source should not be considered.
  • Another participant points out that the switch was at position 'a' for a long time, prompting a discussion about the voltage across the capacitor at t=0+.
  • Several participants emphasize the importance of considering the voltage V(t) at t=0, not just for t>0, indicating a need for clarity on initial conditions.
  • There is a suggestion that the initial voltage across the capacitor at t=0+ could be 10V, with some agreement on this point.

Areas of Agreement / Disagreement

Participants express differing views on whether the 10V source should be included in the s domain transformation. While there is some agreement on the initial voltage across the capacitor, the overall discussion remains unresolved regarding the transformation and its implications.

Contextual Notes

There are unresolved assumptions about the behavior of the circuit immediately after the switch is moved and the definitions of initial conditions that may affect the analysis.

whatphysics
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This isn't a homework question! I posted the question for context purpose.

So I understand that at t>0 the switch moves to b. Hence the first circuit diagram (pictured) I understand.

However for the 2nd circuit diagram (picture 2) when asked to transform to s domain. Why does this answer include the 10/s. To my understanding because the switch already switched to b, the 10V is no longer considered hence shouldn't be included as 10/s in the transformation circuit.

Can anyone explain this to me? Whether the answer key is wrong or are my concepts wrong?

Thank you so much in advance!
 

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The switch was at 'a' for a long time. So what is the voltage across the capacitor at t=0+?
 
As I can see from picture 1, it asks for the voltage V(t) for ##t\geq 0## so we are interested for the V(t) for t=0 too (not only for t>0).
 
Delta² said:
As I can see from picture 1, it asks for the voltage V(t) for ##t\geq 0## so we are interested for the V(t) for t=0 too (not only for t>0).
Ah that would make sense..thanks!
 
cnh1995 said:
The switch was at 'a' for a long time. So what is the voltage across the capacitor at t=0+?
Um 10V?
 
whatphysics said:
Um 10V?
Yes.
 

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