This document discusses different types of clipping and clamping circuits. It describes clipper circuits which remove parts of the input waveform, either the positive or negative portions. Positive clippers remove the positive half cycles, while negative clippers remove the negative half cycles. Biased clippers add a battery to make the diode conduct during only one polarity of the input signal. Clamper circuits add a DC offset to the input waveform without changing its shape. Positive clampers double the wavelength on the positive side, while negative clampers double the negative side. The purpose of these circuits is to protect downstream components from voltages that are too high or low.