This ingenious circuit was found in a 1990s Popular Electronics. The oscillator is a 555 and the keyer uses an optocoupler in the configuration shown.
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...