This 50 Hz rejector or notch filter was found in a 1975 documentation. Other frequencies can be obtained by changing components. The filter uses a Wien network and must use a symmetrical power supply.
This circuit generates 5 notes in sequence, which are programmed in the connections of the 4017...
Featuring an 8 MHz passband, Texas Instruments TVS912A operational amplifiers can be found at...
Emitt This crystal-controlled oscillator can generate signals from 100 kHz to over 30MHz. The...