Figure 25. Waveshapes for shorttime constant

RC circuit.

(4) The output waveforms produced by applying a square wave to

an RC circuit having a comparatively longtime constant are

illustrated in Figure 26. Here the time constant is 10 times as long

as the duration of one complete cycle of input voltage of 20 times

the pulse duration time. Referring to the universal time constant

chart (Figure 20), it can be seen that the capacitor in the circuit

will charge almost linearly for about 20 percent of the firsttime

constant. This causes the waveforms of the capacitor voltage (Figure

26C) and the resistor voltage (Figure 26D) to be linear during the

entire half cycle. This also holds true during the second half of

the cycle when the capacitor is discharging from 20 percent of the

maximum value of E towards zero, and the resistor voltage is

decreasing from minus 20 volts towards zero. On each succeeding

halfcycle, the capacitor charges and then discharges from a slightly

higher value of voltage. Eventually, a point is reached where Ec

varies equally above and below the average value of E, while ER

varies equally

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