Found in a 1924 Gernsback publication this circuit uses 4 batteries for power and loop antenna. Listening is over a high-impedance type earphone or loudspeaker common at the time.
Found in Unitrode documentation from the 1980s, this circuit makes use of PUTs, currently common...
This bidirectional motor control was found in an 80's Electronic Engineering. The circuit uses a...
We found this circuit in the 1972 RCA Linear Integrated Circuits Manual. The circuit can generate...