Engineering [rcl circuits] is this a contradiction?

AI Thread Summary
The discussion centers on the behavior of inductors and capacitors in RLC circuits during different time phases. At t=0-, inductors act as short circuits and capacitors as open circuits, while at t=0+, the circuit enters a transient phase where this behavior changes. The confusion arises regarding the voltage across a resistor at t=0+, questioning whether it is 16V or 0V. Participants clarify that in steady state, inductors revert to short circuits and capacitors to open circuits, but this does not apply during the transient phase. Understanding these transitions is crucial for accurate circuit analysis.
Vishera
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Problem:
upload_2014-9-20_13-52-45.png


Attempt:
Ud54l8w.jpg

But here is what happens when I apply nodal analysis to the same node at t>0:
GH3utpO.jpg


Is this a contradiction? Is the voltage of the resistor at t=0+ equal to 16V or 0V?
 
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I think I figured it out. At ##t=0^-##, the capacitors are replaced with open circuits and the inductors are replaced with wires but this does not apply at ##t=0^+##.
 
When t<0, an inductor acts as a short circuit and a capacitor acts as an open circuit. At the instant t=0+, the circuit goes through a transient phase. Once t>>0, the circuit becomes steady state and once again the inductor acts as a short and the capacitor as an open.
 
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iRaid said:
When t<0, an inductor acts as a short circuit and a capacitor acts as an open circuit. At the instant t=0+, the circuit goes through a transient phase. Once t>>0, the circuit becomes steady state and once again the inductor acts as a short and the capacitor as an open.

Thank you for this. Argh, I wish my textbook explained this to me. Why does the inductor and capacitor act as closed/open circuits in the steady state but not in the transient phase?
 
Vishera said:
Thank you for this. Argh, I wish my textbook explained this to me. Why does the inductor and capacitor act as closed/open circuits in the steady state but not in the transient phase?

Basically an inductor goes from some high voltage to 0, which would cause all the current to flow through it (which is a short) when time goes to infinity. I'm not sure if you've seen the graphs of these, but that should help you, so I'd say look it up.
 

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