What is the voltage in the inductor or capacitor for a short/open circuit?

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Discussion Overview

The discussion revolves around determining the voltage across an inductor or capacitor in a circuit at specific time intervals (t=0+ and t=0-), particularly in the context of a circuit described as being in "dc steady state." The participants are exploring the implications of short and open circuits on voltage measurements.

Discussion Character

  • Homework-related
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant seeks to find the voltages v1 and v2 at t=0+ and t=0- and questions how to derive these voltages given the circuit conditions.
  • Another participant suggests that knowing the current allows for the calculation of voltage across components, specifically mentioning the need to find the voltage across the capacitor.
  • There is a discussion about the meaning of "dc steady state" and its relevance to the time points t=0+ and t=0-, with some participants expressing confusion about the steady state condition at t=0+.
  • A participant proposes that v1 should be found at t=0- when the circuit is stable, and v2 at t=0+ when it reaches a maximum, indicating a belief that these values may be similar at those time points.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of "dc steady state" and its implications for the time points in question. There is no consensus on how to approach the voltage calculations, and the discussion remains unresolved.

Contextual Notes

There are limitations regarding the assumptions about circuit conditions at t=0+ and t=0-, and the definitions of steady state and transient states are not fully clarified. The discussion also depends on the understanding of the circuit elements and their configurations.

Who May Find This Useful

This discussion may be useful for students or individuals studying circuit analysis, particularly those interested in the behavior of inductors and capacitors during transient conditions.

sdfanm16
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Screenshot from 2016-05-13 16-37-12.png

Homework Statement



{Moderator edit: The unlabeled resistance is given to be 3.2 Ω }

finding v1 and v2 at t=0+ and t=0- is needed

Homework Equations

The Attempt at a Solution


Screenshot from 2016-05-13 16-43-03.png

ok I've found the currents by mesh analysis but how can i get the voltage?What voltage is in the inductor or capacitor if its a short/open circuit?
Tal
 
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Now you know the current flowing, you can work out the voltage at any point or the voltage across any component. Find the voltage across the capacitor.

Say find the voltage at the RH end of the 3Ω.
Then the junction of the 1Ω Rs
Then at the 1Ω 3Ω junction. Voila.
 
sdfanm16 said:
finding v1 and v2 at t=0+ and t=0- is needed
The subject says: "dc steady state", yet t=0+ is far from steady state. So which are you wanting to find?

You seem to know that the unlabelled resistor is 3.2 Ω?
 
NascentOxygen said:
The subject says: "dc steady state", yet t=0+ is far from steady state. So which are you wanting to find?

You seem to know that the unlabelled resistor is 3.2 Ω?
yes I've forgot to wrote this. it's given.
 
My guess was that you had to find v1 at t=0- when it is stable and to find v2 at t=0+ when it is maximum.
v2 at t=0- is trivial and v1 at t =0+ I would assume is the same as at t=0- , otherwise you would need to know how + t is!
As t →0 both become more accurate.
 

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