Current in superconductors when a voltage is applied.

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SUMMARY

The discussion centers on the behavior of current in superconductors when a voltage is applied, specifically using a 9V battery. It is established that while superconductors have zero resistance, the current is limited by the internal resistance of the battery, which is typically around 1.5Ω. The correct calculation for current through the superconductor, given this internal resistance, results in a current of 6A, as superconductors can only carry currents below a critical threshold. This highlights the importance of considering non-ideal conditions in superconducting systems.

PREREQUISITES
  • Understanding of Ohm's Law (V = IR)
  • Knowledge of superconductivity and critical current
  • Familiarity with battery internal resistance concepts
  • Basic arithmetic and error-checking in calculations
NEXT STEPS
  • Research the concept of critical current in superconductors
  • Explore the effects of internal resistance in electrical circuits
  • Learn about non-ideal behavior in superconducting materials
  • Investigate practical applications of superconductors in low impedance loads
USEFUL FOR

Physicists, electrical engineers, and students studying superconductivity or electrical circuit theory will benefit from this discussion.

JackA7X
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Suppose you a have superconducting loop connected to a 9V battery. What is the current through it? With a resistance of 0Ω, V = IR gives ∞. I don't think that can be right... If it were, V=\frac{I}{nAe} would give an infinite velocity... Does that equation even apply to superconductors?
 
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Current will be limited by the internal resistance of the battery. This happens for all batteries connected to low impedance loads.
 
So if we assume the internal resistance is 1.5Ω how do you calculate the current through the superconductor?
 
I=V/R, just like always. In this case, 9A since a superconductor has 0 resistance.
 
Marcus
There seems to be an arithmetical error here.
 
Superconductors can only carry currents lower than a critical current value. If the current rises above that limit, they become normal conducting.
 
syhprum said:
Marcus
There seems to be an arithmetical error here.
Quite so, I hit the wrong key on my Blackberry. 6A.
 
Thank you, very helpful.
 
This is a "irresistible force and immovable object" type of question, if you don't allow something to be non-ideal.
 

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