- #1

- 256

- 18

It is my general understanding that according to KCL, current requires a closed loop to flow in DC. However, this is apparently not true in AC; current doesn't needa closed loop to flow.

I have drawn a circuit below which causes confusion:

C1 is a charge capacitor, R1 is a resistor, I1 an inductor, and R2 another resistor, the bottom part of the circuit is the reference, with R2 << R1.

Suppose C1 is fully charged in the above circuit. What is supposed to happen is that all of its charge will leave and flow through R1.

Suppose that we add some kind of AC voltage source to make the voltage across I1 and R2 not zero. So now both parts of the circuit have current flowing between them.

My question is this: will any current from the capacitor go into the second part of the current, across the straight line at the bottom?

Will any current from the right loop go across the line at the bottom, to the left loop? Will any current from the left loop go to the right loop?

Since AC doesn't require a closed loop for current to flow, shouldn't the answer to that question be "YES" ?

I have drawn a circuit below which causes confusion:

C1 is a charge capacitor, R1 is a resistor, I1 an inductor, and R2 another resistor, the bottom part of the circuit is the reference, with R2 << R1.

Suppose C1 is fully charged in the above circuit. What is supposed to happen is that all of its charge will leave and flow through R1.

Suppose that we add some kind of AC voltage source to make the voltage across I1 and R2 not zero. So now both parts of the circuit have current flowing between them.

My question is this: will any current from the capacitor go into the second part of the current, across the straight line at the bottom?

Will any current from the right loop go across the line at the bottom, to the left loop? Will any current from the left loop go to the right loop?

Since AC doesn't require a closed loop for current to flow, shouldn't the answer to that question be "YES" ?

Last edited: