This circuit was found in a Popular Electronics documentation from the 90s. It is possible to switch the frequency of an oscillator by voltage. The circuit can act as a shield.
This circuit with transistors was found in an old Japanese publication, translation of an American...
This 8 W amplifier with germanium transistors was found in a Japanese documentation from 1967. The...
This circuit of the 80's makes use of components of the time. The circuit is from an American...