As an example of the time constant, let the voltage across the capacitor in figure 1-14A be represented by the graph in

figure 1-14B.

When t = TC (one time constant), EC = 63.2 percent of E.

When t = 2TCs (two time constants), EC = 63.2 percent of E + 63.2 percent of the remaining applied voltage after one

time constant. That equals 0.632E + 63.2 percent of 0.368E which is 86.5 percent of E.

When t = 3TCs (three time constants), the capacitor will have acquired another 63.2 percent of the remaining applied

voltage or 95.1 percent of E.

When t = 4TCs, E = 98.2 percent of E and after 5 TCs, EC = 99.3 percent of E. Thus, for practical purposes, the

capacitor may be considered fully

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