Figure 42. Differentiator circuit output for common waveforms

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Figure 42. Differentiator circuit output for

e. In Figure 42C, the input to the differentiator circuit is a

rectangular pulse with finite rise and decay times. Since the

voltage rises at a constant rate to some maximum value, the input

voltage rate of change is constant. After the differentiated output

voltage reaches a steady state, it becomes a positive DC voltage

whose amplitude is proportional to the voltage rate of change and the

time constant. When the maximum value of the input voltage is

reached, the differentiated output voltage drops instantaneously to

zero since the input voltage rate of change is zero. The output

voltage remains at zero during the input voltage duration period.

During the input voltage decay period, the rate of input voltage

decrease is constant and the differentiated output voltage during

this time is a negative DC voltage. Since the input voltage rate of

change is greater during the rise time than it is during the decay

time, the amplitude of the positive DC differentiated output voltage

is greater than the negative pulse.