While I was studying the use of Transistor as an Oscillator from my Fundamentals Of Physics By Halliday, Resnick and Walker , I faced several confusions. My book says that when the switch S1 is closed, the collector current starts flowing , its value slowly increases, as shown by the segment XY and thus emitter current is induced in the input circuit.
My question is why the collector current increases slowly and why Emitter current increases with increase in collector current? Also what is the significance of the cell between base and emitter when it is receiving voltage through mutual inductance? Please help me in the stand.