This 800 Hz sinusoidal oscillator was found in a 1970s American documentation. The transistor supports a modern general-purpose equivalent. The frequency is given by the RC network that can be changed.
This circuit is from a 1976 Motorola CMOS manual. It can be implemented with modern Darlingtons like...
In the figure we have the way of modulating or controlling the frequency of a relaxation...
The purpose of this circuit is to monitor the operation of an alternator in cars with a 12 V...