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 A simple measuring circuit for the measurement of resistance is shown in Fig 1. The galvanometer is first calibrated using a standard resistance of 1 to 10 MΩ (±0.5% or ±1%) and a standard universal shunt is used with the galvanometer. The deflection in cm per microampere of current is noted. The specimen (Rp) is inserted in the circuit and maintaining the same supply voltage, the galvanometer current is observed by adjusting the universal shunt. E - dc stabilized power supply 500 to2000v  V- voltmeter  G- galvanometer 10^-8 to 10^-9A/cm deflection Rsh- Universal shunt Rp-specimen   The resistance of the specimen is given by  𝑅𝑃=𝑉(𝐷×𝐺) Where  D – deflection in cm (with specimen) G – galvanometer sensitivity. 𝐺=(𝑉𝑅𝑠)×(1𝑛)×(1𝐷𝑠) n = the universal shunt ratio, Ds = deflection in cm with the standard resistance in position, Rs = standard resistance used for calibration, and V = the supply voltage Deflection with the specimen in the circuit, will ch...

The shape of specimen and the arrangement of electrode  should be such  that the resistivity can be easily calculated .For a solid specimen, a flat plate with plane and parallel surfaces usually circular are preferred. The specimens are normally in the form of disc of 5 to 10 cm diameter and 3 to 12 mm thickness . A three -electrode arrangement as shown is used for measurement of resistance The electrode which covers the surface of the specimen is called the ‘unguarded’ electrode and is connected to the high-voltage terminal. ➢ The third electrode surrounding other measuring electrode is connected to a suitable terminal of the measuring circuit. ➢ The width of this guard electrode must be at least twice the thickness of the specimen, and the unguarded electrode must extend to the outer edge of the guard electrode. The gap between the guarded and guard electrodes should be as small as possible. The effective diameter of the guarded electrode is greater than the actual diameter...

 WHAT IS RESISTOR ? A resistor is  a passive two-terminal electrical component that implements electrical resistance as a circuit element . In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.