It is a common version but with components calculated for a frequency of 1 kHz. The circuit shown in figure 1 is suggested by Texas Instruments in its Linear Circuits Application. The input impedance is 10k ohms and the power supply must be symmetrical. As in other circuits, it is possible to change the capacitor values, maintaining their relationships to obtain other cutoff frequencies. Remember that the operational amplifier used is the type that uses field effect transistors and therefore has an extremely high input resistance.
