While checking an industrial battery (Exide make) of 2.2 volts analog voltmeter of 0-3V range showed no leakage current between +ve pole and lead ribbon put over the rubber bag containing electrolyte. But a digital multimeter showed a reading of 1.2 Volts. This difference is observed only in one of a total 110 cells. In the rest both digital and analog showed no difference in reading. Also the resistance between the lead ribbon and -ve pole is less than 0.5 MΩ while for the rest of cells it is more than 100MΩ and they showed no leakage voltage. Since there is a drop in insulation there should be leakage votage but still analog meter showed no deflection except a small hunt. Can anyone clarify this anamoly
First you shoud have to understand the basics of Analog & Analog to digital conversion techniques.
Analog meter's moving coil has deflected by Potential with certain level of current ( micro amp llevel,due to friction on pivot ) to show result in volt while digital meter is static device & no friction on measurment & digital meter can read potential with pico amp level drive current to measure volt.
The basic diffrence is drive current for deflection.