1-17 COMBINED LINEAR AND NONLINEAR IMPEDANCES The series combination of a linear and a nonlinear impedance is illustrated in view (A) of figure 1-9. The voltage-current charts of Z1 and Z2 are shown in view (B). A chart of the combined impedance can be plotted by adding the amount of voltage required to produce a particular current through linear impedance Z1 to the amount of voltage required to produce the same amount of current through nonlinear impedance Z2. The total will be the amount of voltage required to produce that particular current through the series combination. For example, point a (25 volts) is added to point c (50 volts) which yields point e(75 volts); and point b (50 volts) is added to point d (100 volts) which yields point f (150 volts). Intermediate points may be determined in the same manner and the resultant characteristic curve (Z1 + Z2) is obtained for the series combination. Figure 1-9A.—Combined linear and nonlinear impedances. Figure 1-9B.—Combined linear and nonlinear impedances.