 A diode clamp (a simple, common type) consists of a diode, which conducts electric current in only one direction and prevents the signal exceeding the reference value; and a capacitor, which provides a DC offset from the stored charge.The capacitor forms a time constant with the resistor load, which determines the range of frequencies over which the clamper will be effective.A clamping circuit (also known as a clamper) will bind the upper or lower extreme of a waveform to a fixed DC voltage level.