This 8-tube amplifier with 12 W output was found in an American publication from 1947. The output is in counterphase with pentode tubes.
This circuit can function as a light alarm by changing the sound when light falls on the sensor....
Based on a unijunction transistor, this circuit was found in the January 1994 issue of Electronics Now...
Although it is a common configuration today, these circuits were taken from an old publication. The...