Wheatstone Bridges Vs Decade Box

Wheatstone Bridges Vs Decade BoxNameTutor’s Name17/09/2014Wheatstone Bridges Vs Decade BoxOhm’s law gives the resistance of a conductor as the potential difference V (measured in volts) between its terminal to the current I (measured in amperes) in the conductor. There are many methods of measuring the resistance of a conductor one of the simplest being employing an ammeter to measure the voltage supplied to the conductor and using a voltmeter to determine the potential difference across the conductor. The resistance is then computed using the Ohm’s law. These simple methods encounter the following difficulties.The need for accurate measurement of a variety of resistances called for meters with several ranges.In computing resistance(R) the resistance of one meter must be known and taken into account.Current heats the conductor and its resistance depends on its temperature.Accurate measurements would require costly meters.To overcome these challenges the Wheatstone Bridge and the Decade box are employed to provide accurate, versatile and inexpensive measurements.The Wheatstone Bridge is a circuit used to compare an unknown resistance with a known resistance. The schematic of a Wheatstone Bridge is as per figure