The integrated circuit used in this application is uncommon today. The circuit is from American documentation from the 1980s. It can be changed to use more modern equivalent components.
We found this circuit in a 1985 technical publication. The circuit uses PUTs to drive lamps....
This high-powered megaphone circuit is from a Radio Electronics from December 1964. Note the use...
This amplifier with differential input uses two old op amps but can be implemented with modern op amps....