First Order Circuit: Replacing Inductor & Current Source

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Homework Help Overview

The discussion revolves around a first-order circuit involving an inductor and a current source. Participants are exploring the implications of replacing the inductor with a short circuit and the behavior of the current source in this context.

Discussion Character

  • Conceptual clarification, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are questioning the effects of short-circuiting the inductor and the status of the current source. There is a discussion about whether the current source can be removed when the voltage across it is zero and how this relates to the current flowing through other components in the circuit.

Discussion Status

The conversation is active, with participants providing insights and clarifications about the behavior of the circuit elements. Some guidance has been offered regarding the current source's operation despite the voltage across it being zero, and there is an ongoing exploration of the current flow through the inductor.

Contextual Notes

Participants are navigating assumptions about circuit behavior, particularly regarding the relationship between voltage and current in the presence of a current source. There is a recognition that the question may challenge intuitive understanding of circuit elements.

Jebus_Chris
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I'm not sure what happens when you replace the inductor with a short circuit. The current source is what throws me off.

One thought I had was that you can remove the 6 and 2 kohm resistors, but then I don't know what ahppens to the current source.
http://imgur.com/lks7y
Thanks
 
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Everything you've said is right. The voltage across the inductor being 0 also means some current is flowing through the 3k resistor. The current source demands a certain current flow, so KCL should give you the inductor's steady current.
 
So then are you saying that you remove the current source as well since the voltage around it is zero?
 
Jebus_Chris said:
So then are you saying that you remove the current source as well since the voltage around it is zero?

The question is designed to trick your intuition. A current source can pull any amount of current no matter what the voltage across it is, including 0 volts.

What you've said about the 2k and 6k resistors is correct -- the voltage across them is zero so Ohm's law gives zero current through them. The current source continues to draw 5mA no matter what.
 
Last edited:
Ok, so then you're saying that there is 2mA of current traveling up [i(0) = -2] through the inductor?
 
Yes, that's it.
 

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