Page 246 - Basic Electrical Engineering
P. 246

or,





                or,


               or,









               where τ = RC = Time constant.


               To write an expression for current i, we will use eq. (i) as


















               or,








               Current I  is the initial charging current when the switch is just turned off.
                          0
               Because at that instant voltage across the capacitor, v  = 0.
                                                                               c


               Therefore,
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