Callender & Griffith's Bridge Dial Type
This instrument is an improvement over the Student's Potentiometer. The 50 cms long side wire of 1 ohm resistance is calibrated into 100 parts to facilitrate calculations. 14 coils are arranged in series in dial from each being of 1 ohm resistance. Accuracy of adjustment 0.1% A 2 volts accumulator through a Rheostat and Key should be connected to terminal P1 to P2 and the P.D. to be balanced on it. The value of Potential Gradient can be found by standardising it through a Galvanometer connected to G.C. The value of Potential Gradient can be found standardising it against a standard cell, and thus it can be made direct reading. Imported Testing Bridge.