Electrical Resistance between 2 points in homogeneous plane?

In summary, there are several methods for determining the resistance between two points in a homogeneous resistive material like graphite. These include using a four point probe or two point probe, where the voltage and current are measured between the two points. However, calculating the voltage difference between other two arbitrary points is more complex and may require finite element analysis.
  • #1
memoguy
29
0
Hi there!

Just say I have large square piece of some homogeneous resistive material like graphite. How would I go about determining the resistance between any two given points?

Further, just say I supply a voltage across two arbitrary points, can I determine the voltage difference between any other two arbitrary points?

I don't even know where to begin with this.
 
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  • #2
See Kelvin probe or four point probe for the measurement of resistance and resistivity.
http://en.wikipedia.org/wiki/Four-terminal_sensing
You can also use two point probe, where you measure the current in the external circuit and the voltage between the two points. The ratio V/I will be the resistance between the two points.

About calculating the voltage between other two points, it can be done but it is not trivial. You will need to do some finite element analysis of your system.
It depend on the geometry of the sample and probe.
 

1. What is electrical resistance?

Electrical resistance is the measure of how difficult it is for an electric current to pass through a material. It is measured in ohms (Ω) and is dependent on the material's properties and dimensions.

2. How is electrical resistance calculated?

To calculate electrical resistance between two points in a homogeneous plane, you can use the formula R = ρ × (L/A), where R is the resistance, ρ is the resistivity of the material, L is the length between the two points, and A is the cross-sectional area of the material.

3. What factors affect electrical resistance?

The factors that affect electrical resistance include the type of material, its dimensions (length and cross-sectional area), temperature, and the presence of impurities or defects in the material.

4. How does temperature affect electrical resistance?

In most materials, electrical resistance increases as temperature increases. This is due to the increased vibration of atoms at higher temperatures, which creates more obstacles for the electric current to pass through.

5. What is the difference between resistance and conductivity?

Resistance and conductivity are inversely related. Resistance measures how difficult it is for electric current to flow through a material, while conductivity measures how easily it can flow. Materials with high resistance have low conductivity, and vice versa.

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