The word transient means “quickly” or short lived, When a voltage source is first connected a capacitor, following happens

· The capacitor gets charged quickly , hence the voltage is built up across capacitor is small fraction of time, due to this quick action , this voltage is called transient voltage . Hence we can also have transient voltage value when capacitor is discharging.

· Similarly , as the capacitor starts getting charged , the current value decreases, in a short interval of time , (transient current)

Transient Currents and its Graph

The formula for transient current can easily be derived using simple calculus, however, in this course scope , we do not need to derive the equation , as we are more interested in understanding the working of equation . The transient equation is given by

The – sign shows that the value of currents decays as the time will increase

Example

Sketch the transient current graph for a the following capacitor for the given instants

 

Time is seconds

· 0

· 0.05

· 0.1

· 0.2

· 0.3

· 0.8