This diagram was found in the November 1972 issue of Radio Electronics magazine in an article describing benchtop equipment. The transistors are of the time and the frequencies are given by the coils.
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...