Found in an old Popular Electronics this circuit is still current. The SCR can be of the 106 series and the relay according to the voltage used in the supply. The voltage can be 12 V.
This old receiver (1967) uses germanium transistors from the time and coupling transformers,...
This circuit was found in old documentation. D1 can be a diac. | Clique na imagem para ampliar...
This oscillator takes advantage of the 2000 ohms headphone inductance as the oscillator circuit coil....