Resistance Measurements
Techniques have been developed to measure resistances from 107 to over 1014 .
Needless to say, specialized instruments must be used at the extreme ends of this range.
We have already seen in Chapter 4 that very accurate resistance measurements are
commonly made using dc Wheatstone or Kelvin bridges and a dc null detector such as
an electronic nanovoltmeter. The values of the resistances used in the arms of these
bridges must, of course, be known very accurately. We shall discuss other dc means of
measuring resistance below.