a npn transistor contain two n-tpyes and 1 p-type. current is a flow of electrons. Like poles repel while opposite poles attract. the n-type consist of excess electrons while the p-type consists of holes(created by electrons moving out of place, leaving a positive electric field). a battery consists of a positive and negative electric field. Knowing all this can some help me figure out how does current flow: from base to emitter; in this case of forward-bias, since the base has a higher potential than emitter? In the case of emitter and collector, if the there is a forward-bias, what direction does the current flow in: from collector to emitter or emitter to collector?