Based on the 4017 integrated circuit, this circuit of a European 303 Circuits from the 90s, generates a pulse train in a relay that mimics the dialing of a telephone.
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...