3 A switched regulator (CB8859E)

Found in a 90s Popular Electronics, this circuit provides a current of 3 to 5 A depending on the transistor.

Telegraphic Oscillator with Visual Indication (CB16279E)
This oscillator for the practice of telegraphy provides a good sound in a loudspeaker, with only...
40 kHz repellent (CB20815E)
This ultrasonic insect repellent was found in American documentation from the 1980s. The...
Experimental Telegraph LM3909 (CB14287E)
The short-wired circuit is suggested by National Semiconductor in documentation on the LM3909. The power...