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.
Based on a CA3059 zero-cross switch, this circuit was found in the July 1995 Electronics Now...
In the figure we have an audio amplifier suitable for portable applications in both mono and...
This 1980s circuit was found in Motorola documentation. The circuit uses period components that admit of...