Found in a 1980s documentation, this amplifier uses an integrated circuit that is not easy to obtain now as it is of the era. The circuit is intended for FI ceramic filter circuits.
This circuit for professional telegraph handlers automatically produces points and dashes. The...
This 100 kHz crystal controlled oscillator was found in an American 1980s documentation. The...
This circuit of an old publication produces the insect-like noise that drives them away. The...