Dumb Circuit Question

[LordFortius]

Assume all wires are perfect and have no resistance. VS is the voltage source, R is a resistor, and C is a capacitor. | and _ are just wire.

+_____R___
VS__|____C
-

Alright, I'm sure most of you will probably think this is a dumb question. It is actually. We are just getting started on circuits, and my question is:

Is this an impossible circuit?

I was thinking that since the wires are perfect, the node before the resistor would suck all the current, but since resistance there is 0, wouldn't that make current infinite, and thus make the circuit impossible? Or do I just ignore that node?

 

[NogginBoink]

Yes, you have a dead short between your + and - terminals.

Therefore no current would flow throught the resistor. But even if the short weren't there, current would only flow through the resistor until the capacitor was charged, because capacitors block DC current.

Yes, with zero resistance you'd have infinite current. If you've got theoretical zero resistance, I'd have to say that you've probably also got theortetical infinite-current-carrying wire in the example.

 

[LordFortius]

Thanks a lot NogginBoink.

By the way, that made me think of another question. What if I change the voltage source to a current source set at something definite, like 10A. Would that change anything?

 

[Heisenberg]

No, not really. Current and voltage are intertwined - you can't have one without the other. Having 0 resistance and 10 A current would still mean 0 v (Ohm's law) which in turn would mean no current can flow, which is contradictory to saying you have 10 A to start with. Anytime you deal with 0 resistance and infinite currents you get into a kind of circular argument. The truth is that Ohm's law breaks down under those kind of conditions and so you can't use it. Not a problem when dealing with every day stuff as 0 resistance is impossible, but when you start dealing with super-conductors and such you can't use Ohm's law any more.