This circuit is from an American documentation from 1975. The circuit uses components of the time which can be replaced by modern equivalents. The coupler is homemade with a lamp and a photocell.
This circuit was found in an English publication. The components are current, and the transformer must be...
This circuit was found in a French documentation from 1982, but it is still current. The source does...
This amplifier for automotive use was found in the SGS manual of linear integrated circuits of...