Found in American documentation from the 1980s, this circuit uses transistors from that time. It generates increasing and decreasing tones when we press and release the push button.
Found in the July 1968 Supertena Bulletin of a Popular Electronics, this receiver makes use of the...
This switching source was obtained in a 1976 National Semiconductor manual. For the indicated...
This configuration appears several times on this site. The circuit can generate a 100 kHz or other...