This commercial radio with 3 earphone listening transistors was manufactured in Japan in the 1960s. The medium-wave circuit uses germanium transistors and is powered by a 9 V battery.
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...