We note that (RMþRS) is the Thevenin resistance that the resistor RX ‘sees’. It is convenient to define (RMþRS) asRH, the half-deflection resistance. That is, when RX¼RH, IM¼IM(FS)/2. Further analysis of the simple series ohmmeter is made simpler by defining the ohmmeter’s fractional meter deflection, F, as: