This very detailed Dimmer was found in an English documentation from the 90's. The SCR could be a modern equivalent like the TIC106. The circuit is only suitable for incandescent lamps.
This circuit for controlling high power in the AC network was found in a Motorola documentation from 1968....
This amplifier is specifically designed for portable radio and recorders with a 4 ohms load....
This circuit was found in a 1973 Radio Elettronica magazine. The Italian magazine no longer...