Absorbing and Delivering Power by the Source
 
It is necessary to distinguish among the absorption of power (or dissipating power) and the generating (or delivering) power. The power dissipated or absorbed by any circuit element whenever flows in a load element from higher potential point (that is, +ve terminal) toward the lower terminal point (that is, -ve terminal). This condition is examined whenever charging a battery or source since the source is absorbing power. On the other hand, whenever current flows in a source from the lower potential point (that is, -ve terminal) toward the higher potential point (that is, +ve terminal), we call that source is generating power or delivering power to the other elements in the electric circuit. In this situation, one can note that the battery is acting as a “source” while the other element is acting as a “sink”. The figure shown below illustrates mode of current entering in an electric element and it behaves either as source (or delivering power) or as a sink (dissipating or absorbing power).  

                                                             Figure: Source and sink configurations