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 configuration with the LM383 appears elsewhere on this site. The circuit shown was obtained...
This circuit was found in National Semiconductor documentation from the 1990s. It has cold...
This simulation shows how to use an operational amplifier as a voltage comparator. The sample uses the...