4-9
Figure 4-8A.—Series-negative limiter with positive bins.
Figure 4-8B.—Series-negative limiter with positive bins.
The series-negative limiter with positive bias is different in only one aspect from the series-positive
limiter with bias (figure 4-5) discussed earlier. The difference is that the diode is reversed and the output
is of the opposite polarity.
Q1. Which portion of a sine-wave input is retained in the output of a series-positive limiter?
Q2. Which portion of a sine-wave input is retained in the output of a series-negative limiter?
Q3. How can a series-positive limiter be modified to limit unwanted negative portions of the input
signal?
PARALLEL LIMITERS
A PARALLEL-LIMITER circuit uses the same diode theory and voltage divider action as series
limiters. A resistor and diode are connected in series with the input signal and the output signal is
developed across the diode. The output is in parallel with the diode, hence the circuit name, parallel
limiter. The parallel limiter can limit either the positive or negative alternation of the input signal.
Recall that in the series limiter the output was developed while the diode was conducting. In the
parallel limiter the output will develop when the diode is cut off. You should not try to memorize the
outputs of these circuits; rather, you should study their actions and be able to figure them out.
