Classification of Resistance

Classification of Resistance Points : Classification of Resistance From the point of measurement, resistances are classified as (i) Low Resistance The resistance of about 1 Ω and under are included in this class. Measurement of low resistances are required for determination of resistance of armatures and series field windings of large machines, ammeter shunts, cable length, contacts etc. (ii) Medium Resistance The resistance ranging from 1Ω to about 100 Kilo-ohms are included in this class. Most of the electrical apparatus in use is of medium resistance. (iii) High Resistance The resistances of 100 Kilo-ohms and above are usually termed as high resistances. This measurement is employed for:
a. Resistance of high resistance circuit elements
b. Insulation resistance
c. Volume resistivity of a material
d. Surface resistivity

As most of the electrical apparatus have medium resistance, so we will describe medium resistance measurement first.