N° of component 

1.4 kHz Double T Filter Passes Range with the 741 (CB1455E)

This circuit was found in a 1977 Radio Shack documentation. The circuit is tuned to 1.4 kHz, but this frequency can be changed by changing the values of the double-T components. The symmetrical power can be made with other voltages and the Crystal or piezoelectric handset monitors the frequency tuning.


Circuit Bench