Shaping is to modify or transform distorted waveforms or different waveforms, and amplification is to expand the amplitude of waveforms.

The amplifier circuit can make a weak small AC signal (superimposed on the DC operating point) pass through a device (the core of which is a transistor and a field effect transistor), and obtain a large AC signal output with similar waveform (no distortion) but much larger amplitude. The actual amplification circuit usually consists of signal source, transistor amplifier and load.