The invention of transistors revolutionized human civilization like no other technology. This video demonstrates working of a Bipolar Junction Transistor (BJT) with it's practical applications such as transistor as an amplifier and as a switch with help of animation. Along with transistor working of diode is also explained in the video. The video covers following topics - structure of Silicon atom, doping, N type doping, P type doping, working of Diode, working of NPN transistor and dual stage amplification.