We found this circuit in a French documentation from the 80's. The components used are still common and the circuit can generate signals from 10 Hz to 100 kHz.
This circuit is recommended for alarm systems since it has a good output stage. The circuit is...
) Suggested by Philips in a 1968 documentation this circuit has very high 10 ohm on-load voltage...
No information is given about the transformers in this circuit suggested by Motorola in a 1968...