The ratio arm is in two dials of 1, 10, 100 and 1000 ohm each. The resistance arm is in three dials having decade of 0.1, 1 and 10. A slide having 0.17ohm resistance is connected in series with unknown L. The slide wire is calibrated into 170 equal parts for easy calculation. A special double key is fitted to bridge. The key is internally connected with terminal for connecting battery and Galvanometer. The bridge can also be used as an Wheatstone bridge.
