Kelvin double bridge for precise measurement of low resistance capable of measuring resistance from 0.1 micro – ohm to 1.1 ohms.
Ten standard resistance of Manganin are provided in step of 0.1 ohm each in dial from with five multiple ratios of .001, 1, 10 and 100 ohms.
The circulars slide wire of .01 ohms is also made from thick Manganin wire.
Having extremely low temperature coefficient calibrated to +05 to 0.02% with heavy construction.
Conforms to Conductor Resistance Test as per
Four Terminals method and kelvin Principle for eliminating contact and lead resistance.
Properly aged manganin wire resistance used.
Reproducible measurements (Same value even after 25000 operations)
Zero setting provision (Provided on slide wire dial)
Hard silver plated switches are used (Specially designed)
Current switch with reverse facility eliminates thermal e.m.f.
Easy to operate
The variable arm of the bridge consists of a decade resistance dial of 0.01 ohms Step (0.01-0.1 ohm)Slide wire dial (white scale)
A graduated slide wire scale is divided in 500 equal parts; the value of one scale division at multiplier 1 is 0.00002 ohms or 0.02 m.Multiplier
A range multiplier consists of double ratio box giving multiplying factor of 0.01, 0.1,1,10 & 100 The value of unknown resistance is given by the sum of main dial & slide wire readings multiplied by multiplier used to measure the unknown resistance.Current reversing switch
A current reversing switch is incorporated to eliminate the difference of readings due to thermo electric e.m.f. A measurement of resistance is to be taken with the direction of current reversed.Press keys
Two press keys marked initial and final are given for galvanometer. And one press key marked DC SOURCE is given for DC source which start and stop the current to flow in the instrument and unknown resistance under test. This press key is provided to avoid the excessive heating.Optional Acc:
DC Source 0-12VDC/10A
Galvalnometer 30-0-30 Division Sensitivity of 2µA/Division