No resistance Circuits

[mdjakhi]

Hi guys,
How do you use ohms law on a circuit with 0 resistance? So, assume there is 10Amps and 0 Ohms on a circuit, how would you find the voltage? (E=IR?)

Also assume you have a circuit with no resistance on it, where would be considered the return path? Like the potential difference I mean from hot to neutral.

 

[dmxtothemax]

because this is just a hypothetical question -
no resisitance = no voltage !

 

[David M]

There's no such thing as no resistance in an electrical circuit, much like there is no such thing as perpetual motion in mechanics.

 

[The Ghost]

Assuming it is a superconductor=0v

 

[Marvo]

Hi guys,
How do you use ohms law on a circuit with 0 resistance? So, assume there is 10Amps and 0 Ohms on a circuit, how would you find the voltage? (E=IR?)

Also assume you have a circuit with no resistance on it, where would be considered the return path? Like the potential difference I mean from hot to neutral.

If the circuit has no resistance it's a perfect short circuit. This is only possible theoretically, not in the real world. With a zero resistance circuit the current flowing would in theory be infinite but in this case you'd need to look at the whole circuit including the source of the power, not just the final circuit that supplies the load because the internal resistance of the power source becomes the limiting element.

 

[Des 56]

If you can hang on to this no resistance circuit,the world will rejoice at your feet
The good and the great will bow down to you.untold riches will be bestowed upon you and your name will live long in the history books

Somehow I fail to see that happening,probably a more accurate test meter may scupper this fantastic future

 

[DPG]

In defence of the OP, it is a good question to ask. Hopefully the replies above have answered it! Daz

 

[David M]

In defence of the OP, it is a good question to ask. Hopefully the replies above have answered it! Daz

These type of questions get raised on many of the science forums I'm a member of.
The problem is they often start with a premise that is not possible in the first place. So, yes I agree its a good question in that its quite easy to answer and understand. So long as its accepted that there is not always continuity between the hypothetical and actual reality.

 

[telectrix]

if there were such a thing as zero resistance, my knees would allow me to get up off them in zero seconds, instead if the 2 minutes it takes now.

 

[HandySparks]

if there were such a thing as zero resistance, my knees would allow me to get up off them in zero seconds, instead if the 2 minutes it takes now.

That would be gravity, then. Get yourself a job as resident electrician on the moon; much easier.

 

[telectrix]

if only:

 

[stummish]

If you get 0 ohms on a circuit contact CERN immediately to collect a free Nobel prize! Surely 0 ohms would give you infinate amps, and any PD on the circuit will trip in an infinaltely short time. Divide by 0 and the universe will implode, the ultimate PD!

 

[dmxtothemax]

Ignoring for now weather it is or isn't possible in practice,
I always thought that to have a voltage ( or potential difference )
then you need current flowing between two points
with a resistance between these points.
this is what gives you potential difference or voltage
Am I correct or not ?
SO NO RESISTANCE CAN ONLY = NO VOLTAGE ?

 

[Richard Burns]

Ignoring for now weather it is or isn't possible in practice,
I always thought that to have a voltage ( or potential difference )
then you need current flowing between two points
with a resistance between these points.
this is what gives you potential difference or voltage
Am I correct or not ?
SO NO RESISTANCE CAN ONLY = NO VOLTAGE ?

Yes V=IR so if R is zero, V is zero.
There can be no voltage drop over a zero resistance, therefore no potential difference.
i.e. the two ends of the zero resistance conductor are at the same potential.

 

[dmxtothemax]

Nuff said !
Time for a beer or two or three.

 

[charlie76]

Ignoring for now weather it is or isn't possible in practice,
I always thought that to have a voltage ( or potential difference )
then you need current flowing between two points
with a resistance between these points.
this is what gives you potential difference or voltage
Am I correct or not ?
SO NO RESISTANCE CAN ONLY = NO VOLTAGE ?

No, you don't have to have a current flowing between the 2 points at all. The potential difference is the difference in potential between the 2 points. The potential to make a current flow between the 2 points. The resistance could be infinite between the 2 points and so no current is flowing but the potential still remains.

2 cables held apart one at 50V and one at 0V, there is a 50V potential difference between them. Touch them together there is now no resistance between the two ends (in a perfect conductor) measure the voltage now 0V as there is no potential difference, they are both at the same potential, 50V, current will now flow. Obviously the current is restricted to the supply source and the resistances in the circuit.

 

[Dangerous Brian]

CERN already use zero resistance conductors for the magnets in the LHC. This link explains a bit about superconductivity,
Superconductivity, Superconductivity - http://hyperphysics.phy-astr.gsu.edu/hbase/Solids/scond.html

 

[stummish]

I didn't realise CERN has 0 resistance conductors. I know they cool it (gold? conductors) down to a few degrees off 0°K. If I had the time I'd look it up, interesting forum topic this has turned out to be!

 

[Des 56]

It has been said that Superconductivity at room temperatures remains a very very very distant prospect (if it ever has been considered a prospect or even possible in the first place)