60's crystal radio (CB22171E)

Found in an English publication from the 1960s, this circuit uses period components, including the commercial grade coil.

FM transmitter (CB12125E)
This circuit is from a publication by Newton C. Braga in the United States. The transistor can be...
Triac Photoelectric Switch (CB13222E)
This circuit is from an old publication from the 70s, but it can be implemented with modern diacs...
800 Hz Pulsed Tone Generator (CB25519E)
This circuit is recommended for alarm systems since it has a good output stage. The circuit is...