This blocking oscillator configuration was found in a 1964 American book. The circuit can be designed with modern transistors and the frequency depends on the transformer.
This circuit produces a signal at a frequency of 455 kHz, based on a ceramic resonator CSA455E, by...
This simple unijunction circuit is from a Radio Electronics from July 1963. It can be assembled with a...
Hughes suggests this circuit in a 1968 documentation. The circuit uses old transistors that can be...