DC CircuitsINDUCTANCEThe relationship between values of current reached and the time it takes to reach them is calleda time constant. The time constant for an inductor is defined as the time required for the currenteither to increase to 63.2 percent of its maximum value or to decrease by 63.2 percent of itsmaximum value (Figure 7).Figure 7 Time ConstantThe value of the time constant is directly proportional to the inductance and inverselyproportional to the resistance. If these two values are known, the time constant can be foundusing Equation (3-5).(3-5)T_{L}LRwhereT_{L} = time constant (seconds)L = inductance (henries)R = resistance (ohms)Rev. 0 Page 5 ES-03

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