This filter, which rejects frequencies around 1 kHz, was found in the August 1993 Electronics Now magazine. The fine tuning is done at R3, and the source must be symmetrical.
This circuit automatically inverts the test leads connection according to the polarity of the...
This circuit was found in a publication from the 90s. The circuit can be assembled with modern...
This filter, from an audio publication from 1977, passes the frequency range corresponding to the...