You can readily see that the formula comparison of the forward- and reverse-bias resistance
conditions shows that a small amount of reverse current will flow during the limited portion of the input
waveform. This small amount of reverse current will develop as the small positive voltage (0.09 volt)
shown in figure 4-2 (T0 to T1 and T2 to T3). The actual amount of voltage developed will depend on the
type of diode used. For the remainder of this chapter, we will use only idealized waveforms and disregard
this small voltage.
SERIES-POSITIVE LIMITER WITH BIAS.In the series-positive limiter (figure 4-1, view
(A)), the reference point at the bottom of resistor R1 is ground, or 0 volts. By placing a dc potential at
point (1) in figure 4-3 (views (A) and (B)), you can change the reference point. The reference point
changes by the amount of dc potential that is supplied by the battery. The battery can either aid or oppose
the flow of current in the series-limiter circuit. POSITIVE BIAS (aiding) is shown in view (A) and
NEGATIVE BIAS (opposing) is shown in view (B).