This operational clamping circuit was found in an American documentation from the 1980s. The source must be symmetrical, and the waveforms of the signals are given next to the diagram.
White noise applied to an audio amplifier can be used as a relaxant, since it resembles the noise...
This voltage sensor limits the discharge of a Nicad battery. We found it in an American...
This is a circuit of an 80's American documentation and can be implemented with modern components....