Found in a 1967 Electronics World, this preamplifier uses an integrated circuit from that time, difficult to obtain today. The maximum frequency is 15 kHz.
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...