How can I better understand transistors and their various uses?

[Yashbhatt]

I am having troubles understanding the working of a bipolar junction transistor(and also its uses as switch, amplifier, oscillator etc.).

Can anyone recommend any good book or video explaining it?

 

[SredniVashtar]

Sedra and Smith, "Microelectronic Circuits" - any edition, for an elementary formal introduction
Horowitz and Hill, "The Art of electronics" - any edition, for an elementary informal introduction
Millman's Electronics, for an introduction.