Superconductor at room temp

[Jlarkin84]

I have a question. What device can I use to measure resistance lower than .000000001? Conductor is 6 inches by 1/4 thick. I had to make it big due to equipment limitations

 

[renormalize]

What device can I use to measure resistance lower than .000000001?

That's one nano-ohm, which could be tough to measure!
Take a look at this white paper from Tektronix: Accurate Low-Resistance Measurements Start with Identifying Sources of Error, which states:
"Measuring low resistances (1Ω and lower) has a variety of technical challenges. Depending on the application, test system builders can choose from various instrument options, including a nanovoltmeter used with a current source (for measurements as low as of tens of nano-ohms) or a digital multimeter (DMM) optimized for low-resistance measurements (as low as tens of micro-ohms)."

 

[berkeman]

Welcome to PF.

I have a question. What device can I use to measure resistance lower than .000000001? Conductor is 6 inches by 1/4 thick. I had to make it big due to equipment limitations

Have a look at this recent thread (click the little up-arrow in the title bar of the quote to be taken to that thread):

TL;DR Summary: Testing superconductor

Hi, I would like someone to test the superconductor I have come up with or let me know how ( I don't have a lab ), what I can say that the resistance is almost zero with my Fluke.Regards

 

[Baluncore]

The measurement of low resistance is always difficult due to the contacts with the material. Low-resistance measurements invariably use four terminal connections. On a plate, those electrodes would be in a line, centred on a face of the plate. The two outer terminals provide a measured current that flows across the plate. The two inner terminals are used to measure the voltage drop at the surface. The geometry of the plate, determines the current density, with the voltage drop, between the inner electrodes, being proportional to the resistance.

A superconducting plate will make a good mirror to long-wave radiation. One way to measure plate resistance, would be to heat it with an induction coil. If the plate remains cold, it has low resistance and is reflecting all incident EM field.

Could an IR thermometer measure the temperature of a superconducting plate? Or would you simply be measuring your body temperature in the mirror?

 

[marcusl]

You may not be aware that there are no room temperature superconductors—yet. Superconductors expel magnetic fields, so one way to tell if you have a superconductor is to place it in a uniform magnetic field, cool it through the transition temperature, and watch the external fields change.

 

[Baluncore]

Superconductors expel magnetic fields, so one way to tell if you have a superconductor is to place it in a uniform magnetic field, cool it through the transition temperature, and watch the external fields change.

Another way would be to place the sample in a solenoid inductor. The inductance will fall when the sample becomes superconducting, as it will exclude the magnetic field from that part of the solenoid. Changes in inductance can be measured very accurately.

 

[Jlarkin84]

You may not be aware that there are no room temperature superconductors—yet. Superconductors expel magnetic fields, so one way to tell if you have a superconductor is to place it in a uniform magnetic field, cool it through the transition temperature, and watch the external fields change.

I have a question. What device can I use to measure resistance lower than .000000001? Conductor is 6 inches by 1/4 thick. I had to make it big due to equipment limitations

Thank yall!. I looked up the cost of the equipment for nanoohms and that ain't happening. To rich for my blood. I did buy a milliohm meter and it can't determine resistance either. So I read one of those threads and gonna do what yall suggested them, take it to a lab. Safran is gonna help me out. They have that nanoohm device and experience to use it. Ty!!

 

[marcusl]

So you’ve invented a room-temperature superconductor?

 

[Rive]

Conductor is 6 inches by 1/4 thick.

Not actual measurement, but kind of a cheap comparison which works just fine for bigger plates/pieces:

 

[DaveE]

Or would you simply be measuring your body temperature in the mirror?

I've seen that problem with TO-3 transistor cases. We had to paint them sometimes.