This circuit was found in documentation for radio amateurs of the 1980s. The circuit is intended to produce a tone for modulation in telegraphic transmissions.
Found in a 90s Popular Electronics, this circuit is interspersed between the filter and the...
This circuit is from an 80's documentation. The integrated circuit is from the time and the...
This circuit was found in a 80s American documentation. The zener diodes determine the points of...