It is used to determine variation of resistance of a conductor with changes in length, material, diameter and the effect of series and parallel combination of resistances, this item is used. Ohm’s Law may also be studied. The whole unit is mounted on a sheet-metal base, size: 12.5 x 110cm. There are 4 nos. of separate wires having length of 1 m each. The wires are constantan 24 swg, constantan 30swg, iron 30swg and Copper 30 swg. Each wire may be attached separately to binding posts. Ohm’s Law may also be studied with the help of DC power supply and multimeters.