This PA or Public Address amplifier with a few watts of power was found in the March 1986 Radio Electronics magazine. It uses two LM380 ICs in bridge mode for higher power.
In the figure we have three voltage doubler configurations that can be used in high and low...
In this application, from English documentation, we have the way to activate an AC load up to 10 W...
This 1-transistor reflex receiver was found in a 1963 publication. The coil is for the mid wave...