This 80's circuit uses a microcontroller programmed to generate various songs. The circuit can serve as the basis for a modern design, for example using Arduino. The old circuit included a small audio amplifier.
This circuit determines the frequency of a signal by beating with a known signal. The circuit was...
This converter for WWV time reference station signals was found at Popular Electronics. The 15 MHz...
This circuit was obtained from an 1974 Everyday Electronics magazine. The circuit is still current as...