We found this Vox in a 1969 Motorola documentation. Transistors support modern equivalents and the SCR can be a TIC106. The reset is done by a push button.
This circuit is from a Mallory 1968’s documentation. The integrated circuit is of the time and the...
Of course, other frequencies can be generated by changing the components. The circuit generates a...
This circuit is from National Semiconductor using an LM11, which is uncommon nowadays. The circuit...