This 5-tube hi-fi amplifier was found in an American publication from 1947; The output is in class B and the circuit uses a source with transformer.
This 100-second timer was found in a 2000 Poptronics. The magazine no longer exists, but the...
This good amplifier with output in complementary symmetry is from an old publication, and modern...
This 5.1 MHz oscillator was found in a 1980s American documentation. The used operational...