This low frequency circuit was found in documentation from the 1980s. The values of R and C determine the frequency. Inverters can also be designed with logic gates.
The circuit shown in the figure is suggested by ON Semiconductor (www.onsemi.com), based on its...
September 2016 - can be found at Mouser Electronics the new amplifiers with digital variable gain...
This simple 1-transistor audio preamplifier appeared in the June 1968 Radio Electronics magazine. The...