Circuit diagram of two stage amplifier :
Need of multistage amplifier: The output from a single stage amplifier is usually insufficient to drive an output device. So that additional amplification over two or three stages is necessary.
To achieve this, output of each amplifier stage is coupled in some way to the input of the next stage. The resulting system is referred to as multi-stage amplifier or cascade amplifier, where the output of first amplifier is fed as input to second amplifier.
To increase the overall gain of the amplifier multistage amplifier is needed.