This commercial radio for the AM band was sold in Japan in the 1960s. The circuit has an IF of 455 kHz and is powered by batteries. The push-pull output gives a good audio power.
This simple circuit was found in a 1981 publication. As readers can see, we have an H switch and...
This circuit is from 2001 documentation with the purpose of controlling a pump that fills a water...
This simple CMOS metronome circuit can be mounted in a small box, providing both sound and light...