Found in a 1947 publication, this 7-tube amplifier uses four tubes in the output stage. The circuit uses a power source with a transformer.
This circuit is from a 1968 documentation using one of the first integrated circuits available at the...
This circuit appears elsewhere on this site. This is from an American 80's circuit manual....
This circuit consists of an inverter powered by only 4.5 V. The circuit is from a 1967 Mullard...