This filter was found in a Texas Instruments manual based on an operational amplifier 741. Other operational can be used and, with the indicated components, the rejection frequency is 2 kHz.
This circuit is from an old American documentation using as indicators for the flip-flops neon...
This stereo circuit is from Japanese 1960 documentation. The circuit was originally designed to...
This circuit is from the 1983 Intersil Databook. The display is plasma and must be excited by a...