This 1969 Mullar circuit appears elsewhere on this site. The circuit uses germanium diodes and the indicator is microammeter with zero in the center of the scale.
Found in an American documentation from 1968, this circuit uses transistors from the time. The...
This circuit is based on an LM123 and can supply output currents up to 3A. IB is typically 3.5A...
This experimental radio was obtained in an old Argentine publication. Germanium transistors are...