The circuit, shown in the figure, is suggested by Texas Instruments, making use of one. Frequency is determined by the capacitors, which can have their values changed, so that another cut is obtained. As it is a first order filter, its attenuation below the selected frequency is 6 dB per octave. The power supply used must be symmetrical and equivalent integrated circuits can be used. Operational amplifiers with field effect transistors must be used at the input.
