This circuit was found in Radio Electronics from the 90s. It converts capacitance into frequency in order to obtain a proportional voltage that can be measured in a common multimeter.
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...