This circuit is used to protect an amplifier from excessive power output that would cause problems for the speakers. The circuit is from the January 1985 issue of Radio Electronics magazine.
This well-known configuration that appears elsewhere on the site is from an English documentation. In it,...
We found this simple operating tester 741 in a European publication in 1991. The circuit...
Found in Radio Electronics, this circuit doubles the voltage of the 117V power grid to activate...