## Measurement of earth resistance by fall of potential method

On these factors the resistance of earthing system are depends- Shape and material of electrode or electrodes used. Depth in the soil at which the electrodes are buried. Specific resistance of soil surrounding and in the neighborhood of electrodes. The specific resistance of the soil varies from one type of Read more…

## Megger method for measurement of high resistance

Construction- A megger is a portable device which is used for the measurement of high resistance. The component of megger are Permanent magnet C shaft Hand driven generator Resistances RC and RD Two Coils- Control coil (Cs) Deflection Coil (Cd) Working Principle- As current provided by the hand driven generator Read more…

## Voltmeter-Ammeter method for measurement of medium resistance

In the figure let us assume the voltmeter to be ideal (internal resistance Rin=infinite). So current Iv=0A I= IA+IV I=IA       [IV=0A] V=VA+VK V=I×RA+I×Runknown Ammeter is  not ideal here. V=I(RA+ Runknown) V/I= RA+ Runknown            [V/I= Measured value of resistance] RM=RA+ Runknown So the measured value of resistance is greater than the Read more…

## Method of substitution for measurement of medium resistance

E= External battery R= resistance to be measured S= Variable resistance R= Turning resistance Sw= Switch A= Amperemeter The position of the switch is at a point 2 with the battery E makes a close loop with resistance r, ammeter and the unknown resistance R. There will be a deflection Read more…

## Measurement of resistance

Measurement of resistance- Properties of resistance plays an important role in determining performance specification for various circuit elements including coil, winding, insulation etc. Apart from this resistor are use as standard for measurement of other unknown resistances and for the determination of unknown inductance and capacitance. For the point of Read more…