Two problems arise with this circuit when measuring RXs 41010 . The bias current must be kept much less than IS and if Ci is of the order of several hundred pF, the ohmmeter’s response time constant can become significantly long (tens or hundreds of seconds), requiring excessive time to obtain a steady state reading. If we assume that full scale deflection of the normal mode electronic ohmmeter is vo(SS)¼1V, then full scale resistances from 1–1010 can be measured with IS values ranging 10mA–1pA, respectively, with (1þR1/R2)¼100.