This circuit with RIAA equalization is from 1985 US documentation. The circuit has a flat response of 150 Hz to 40 kHz. The power supply must be symmetrical.
We found this crystal AM radio using a germanium diode in a Japanese magazine in 1967. The circuit...
This filter was found in Radio Electronics, and its configuration can be applied to any...
This circuit was obtained in an old English magazine (TSI) 1998 and consists of a Schmitt trigger...