This circuit is from an old Japanese publication of 1962. The circuit uses two batteries, one for the filaments of the tubes and the other one of high voltage for the plate circuits.
This oscillator for testing resonant circuits was found in a Radio Electronics magazine from June...
This circuit, suggested by an old American publication, allows you to use the AM radio antenna of a...
This circuit limits (clip) the intensity of a signal, according to the setting of P. The circuit is...