- - resistivity table;
- - tester.
Identify the material from which made the conductor.Thereafter, in the table and find the resistivity of this material.Note that there are generally two supplied values.One in Ohm ∙ m - it is taken in the case in the calculation section of the conductor is measured in meters.If the section of the conductor to be measured in mm², in this case, better to take the value in ohms ∙ mm² / m.
In case conductor material is unknown, locate the resistivity of yourself.To this end, using a tester, switch to an ohmmeter, get the electrical resistance of the conductor in ohms.Then, a tape measure or ruler, measure the length, in meters, and the caliper diameter in millimeters.To calculate t
he number of conductor resistivity of 0.25 to multiply the electrical resistance, and the number π≈3,14 conductor diameter squared.Divide the resulting number by the length of conductor ρ = 0,25 ∙ R ∙ π ∙ d² / l.Where R - the electrical resistance of the conductor, d - diameter, l - length of the conductor.
If for any reason, find the resistance of the conductor itself is not possible to determine this value using Ohm's law.Connect the conductor to the power supply.Connect it to the tester is configured to measure current, consistent, and measure the current flowing through a conductor in amperes.Then, switch the tester to measure voltage and connect it to the conductor in parallel.Get the value of the voltage drop on the conductor in volts.If the conductor is connected to a DC power source, when you connect the tester observe polarity.Find the resistance of the conductor by dividing the voltage at a current of R = U / I.Then calculate the resistivity of the above described procedure.