This circuit was found in a 1980s documentation. Similar configurations appear in the section, but from different sources. The circuit makes use of components of the time.
In the original 1992 application, this passive circuit was intended for use in the car. At that...
This 1995 circuit uses an audio amplifier that is no longer common today. However, other...
This circuit is from an 80's documentation. The integrated circuit is from the time and the...