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Current Source in Parallel with Short Circuit

  • Thread starter nickadams
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  • #1
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Homework Statement



Which of the following are self-contradictory combinations of circuit elements?

- A 2 Amp current source in parallel with a short circuit.

Homework Equations



KVL- "the sum of voltages around a closed loop amounts to 0.
KCL- "the current into a node equals the current out of a node.
Ohm's Law- V= IR

The Attempt at a Solution



The answer key says this is not contradictory, but I don't see how we can have such a circuit... If we had a short circuit parallel to a current source wouldn't all the current go into that short circuit branch and ignore the other branches? Then we'd just have a loop of 2 Amp current with no voltage drop... Why wouldn't that violate KVL?
 

Answers and Replies

  • #2
ehild
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An ideal current source provides a given current no matter what the load is. The voltage across it is equal to the generator current multiplied by the loading resistance, zero for a short-circuit. Where is contradiction?
 
  • #3
Bystander
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What are the other choices you're given?
 
  • #4
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An ideal current source provides a given current no matter what the load is. The voltage across it is equal to the generator current multiplied by the loading resistance, zero for a short-circuit. Where is contradiction?
I just always thought that in order for current to flow between two points we need a voltage difference...

What are the other choices you're given?
I understand the rest of them... It was only this one I was hung up on
 
  • #5
ehild
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I just always thought that in order for current to flow between two points we need a voltage difference...
What is the voltage difference across zero resistance according to Ohm's Law?
 
  • #6
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What is the voltage difference across zero resistance according to Ohm's Law?
V=IR so V=I*0=0. Ok I think I see now
 

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