This Mullard circuit was found in a 1969 documentation. It uses complementary transistors on the output and does not need a transformer. The bandwidth goes from 100 to 20 000 Hz.
This circuit was obtained in an old publication of 1978. The integrated circuit is the critical...
When an alternator is used to supply constant current, it needs an adjustment that must be made as...
This timer, from an old American publication, uses indicator lamps, but can be modified to use...