Found in 1968 Mullard documentation, this circuit uses period components. The transistors are matched pairs and the sensor is an Indian photocell of the time.
This circuit uses a 100 kHz crystal, but nearby frequencies can be obtained with appropriate...
The component used in this circuit that we found in an old documentation, is not easy to obtain...
This oscillator uses germanium transistor avaialble in 1958 when the project was published....