The discussion revolves around the behavior of a capacitor in an RC circuit, specifically addressing the conditions under which a capacitor is replaced by an open circuit or a short circuit. Participants explore the implications of these replacements in the context of determining the time constant and Thevenin resistance.
Participants express uncertainty about the replacement of the capacitor with a short circuit and whether there are alternative methods to achieve the same results. No consensus is reached on the best approach or the reasoning behind the capacitor's replacement.
Participants mention the need to analyze the circuit to determine the time constant, indicating that the discussion may depend on specific definitions and assumptions related to circuit analysis methods.
They were looking for the resistance that the capacitor "sees" in order to determine the time constant, RC. One way to do that is to remove the capacitor and determine the Thevenin resistance as seen at those terminals. The author of the solution decided to find the Thevenin resistance by determining the short circuit current and the open circuit voltage. Divide the voltage by the current and voila, Thevenin resistance. That short circuit for the capacitor is just the application of that method.sammyqw said:
Is there any other way to find the same answer that you may know? Thanks for your help.gneill said:
I suppose one could work out and solve a differential equation for the circuit, but that would likely be a lot of work for the same result. Or one could analyze the circuit using Laplace Transforms, again arriving at the same result after more work than necessary.sammyqw said: