Finding Initial Current and Natural Response in an RL Circuit

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Discussion Overview

The discussion revolves around solving an RL circuit problem, specifically focusing on finding the initial current through an inductor and analyzing the circuit's behavior after a switch is opened. The scope includes theoretical aspects of circuit analysis and practical application in a homework context.

Discussion Character

  • Homework-related
  • Technical explanation
  • Exploratory

Main Points Raised

  • One participant expresses difficulty in determining the initial current through the inductor and managing the dependent source after the switch is opened.
  • Another participant questions the nature of a diamond-shaped component in the circuit, suggesting it may be a current controlled voltage source, and asks for the equations the original poster has set up.
  • A later reply reiterates the question about the diamond-shaped component and emphasizes the need for the original poster to show their work.
  • The original poster later claims to have figured out the problem, stating that at t=0- the inductor behaves as a short circuit, and the initial current is simply the current through a 4.5 Ohm resistor.
  • The original poster also mentions that to find the current iL(t) for t >= 0, one must use the natural response equation for the inductor's current and suggests finding the equivalent resistance (Req) through Thevenin's theorem.

Areas of Agreement / Disagreement

There is no clear consensus among participants. While the original poster claims to have resolved the problem, others have posed questions and sought clarification, indicating ongoing uncertainty and differing perspectives on the circuit analysis.

Contextual Notes

The discussion includes assumptions about circuit behavior, such as the inductor acting as a short circuit at t=0, and the need for Thevenin's theorem, which may depend on specific circuit configurations not fully detailed in the posts.

csmix
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Can anyone please help me slove this example circuit i found.
im having a hard time finding the initial current through the inductor and duno how to deal with the dependent source and inductor after the switch is opened.
 

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What's the diamond shaped thing? Is that a current controlled voltage source or a current controlled current source?

What equations have you been able to set up so far? Is this a homework problem?
 
berkeman said:
What's the diamond shaped thing? Is that a current controlled voltage source or a current controlled current source?

What equations have you been able to set up so far? Is this a homework problem?

Looks like a current controlled voltage source.

To the OP -- you're going to have to show some work, like berkeman said.
 
thanks for feed back but i have figured it out. If anyone else needs help with this circuit i'll get u guys started. to find initial current at t=0- the inductor is a short circuit so Io is just the current through the 4.5Ohm resistor.

After the switch is closed to find iL(t) for t >=0 you will need to use the natural response equation for the current of an inductor which means u will need to find Req for tao. to find Req u need to thevenize the circuit by creating an open circuit at the inductor and finding Voc=Vth then the R in the standard form would be Vth/Itotal.
 

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