This circuit was found in a 1966 EEE. The circuit uses transistors from the time but can be made with modern equivalents. The operating frequency ranges from 0.1 to 1 kHz.
We have in the figure a traditional amplifier configuration with operational amplifier. The source...
This circuit was found in a 1977 Radio Shack documentation. The circuit is TTL, which must be...
This circuit is suitable for modulating small FM transmitters for eavesdropping or espionage. The...