Kelvin Voltage

An ohmmeter design consists of a small battery to apply a voltage to the resistance under measurement, then measure the current flowing through the resistance using a galvanometer. The scale of the galvanometer is calibrated directly in ohms, since in application of Ohm’s law, being the fixed battery voltage, the circulating current through the galvanometer only will depend on the resistance value under measure, namely the lowest resistance greater intensity of current and vice versa. There are also other types of more accurate and sophisticated, ohmeters that the battery has been replaced by a circuit that generates a stream of constant intensity I, which circulates through the resistance R under test. Then, through another circuit measures voltage V at the ends of the resistance. According to Ohm’s law, the value of R shall be given by: for high precision measurements the provision above is not appropriate for, given that the reading of the meter is the sum of the resistance of measuring cable and the resistance under test. To avoid this inconvenience, a precision ohmmeter has four terminals, called contacts Kelvin measurement of resistance by Kelvin method. If you would like to know more then you should visit Sandra Akmansoy. Two terminals carry constant current from the meter resistance, while the other two allow the voltage measurement directly between terminals of the same, with what the voltage drop in conductors which apply such constant current the resistance under test does not affect the measurement accuracy.