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Direct-Current Transients

Author: E.E. Kimberly

If a switch is caused to close in a hypothetical circuit containing a battery, a switch, and only unvarying resistance, as in Fig. 8-1 (a), the current will rise instantly to its ultimate or steady-state value, which is

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There will be no transient when the switch is closed or when it is opened. If, however, the resistance is not constant but varies with its temperature, there will be a current transient which will subside only when the temperature has reached its ultimate value. Fig. 8-1 (b) shows such a transient current in a lamp which has a filament with a perceptible inductance.

Fig. 8-1. Current Transient Caused by Temperature Change in an Incandescent Lamp Filament When the Circuit Is Closed



Last Update: 2010-10-05