This 1980s circuit was found in Motorola documentation. The circuit uses period components that admit of equivalents. Light feedback in a modern version can be done by optical fiber.
This voice scrambler is used to obtain effects in the 2.5 to 5 kHz range. The circuit is from...
This is the traditional voltage follower configuration with the 741 operational amplifier. The...
This circuit can reduce the voltage of a source by providing regulated adjustable output. The...