How to Convert S/Cm to Ohms

Conversion between S/cm and Ohms can be performed using a calculator, a ruler and a formula.

Electricity is created by the flow of sub-atomic charged particles called electrons. As electrons flow through a wire, they scatter off each other and off wire boundaries. This phenomena is known as resistance and it is generally measured in Ohms. The inverse quantity is called conductance and is a measure of how well an electrical current flows through a wire. The unit of conductance is Siemens (S). Conductivity is a related quantity and is the conductance per unit cross-sectional area (S/cm). A routine task in electronics and physics is the conversation between resistance and conductivity.

Things You'll Need

• Calculator
• Ruler

Instructions

1. Measure the length of the wire whose resistance needs to be determined. Write down the value in centimeters (cm).

2. Determine the cross-sectional area of the wire. This can be determined from the specification, which will normally give the radius of the wire. The cross-sectional area of a circular wire is: 3.142 x r x r, where r is the radius of the wire. The cross-sectional area must be measured in centimeters square (cm^2).

3. Solve the formula for resistance. The conductivity is equal to

   C = l / (R x A)

   where C is the conductivity of the wire, l is the length of the wire, A is the cross-sectional area, and R is the resistance of the wire.

   Rearrange the formula to make R the subject:

   R = l / (C x A)

   Plug in the numbers for length of wire, conductivity and cross-sectional area into the equation. The result is the resistance in Ohms.

References

• Hyperphysics: Resistivity and Conductivity