Higly sensitive instrument to be used as null detector in wheatstone bridge and potentiometer experiments, with built in lamp and scale arrangement in bakelite case, a sensitive moving coil system is suspended in a taut band manner in a uniform field of permament magnet. Zero adjustment knob is provoed to set spot of light. time period app 1.58 second working on 220 V AC available in two different coil resistance. Available : 100 / 600 ohms
