This circuit was found in a documentation for radio amateurs from the year 70. Its purpose is to produce a tone on a transducer when transmitting messages in SSB telegraphy.
This circuit was obtained from an American documentation from the 1980s. The T1 triggering...
Found with variations on this site, this circuit was taken from an American documentation from the...
With the original components, suggested in a Motorola documentation from 1971, this circuit can...