a regenerative circuit is an amplifier circuit that employs positive feedback (also known as regeneration or reaction). some of the output of the amplifying device is applied back to its input so as to add to the input signal, increasing the amplification. one example is the schmitt trigger (which is also known as a regenerative comparator), but the most common use of the term is in rf amplifiers, and especially regenerative receivers, to greatly increase the gain of a single amplifier stage.