Designed circuit

(1) Determine the amplification unit device: choose the integrated operational amplifier TL082. Since the input impedance of TL082 is as high as 10lzn and
has the characteristics of high input impedance, it can well meet the requirements of the control characteristics and only needs to use a small-capacity capacitor.
    (2) Calculate the turning frequency point where, Fu: Using the rule that the slope of the control characteristic is 6d3 per octave, and
the requirement of ±12dB improvement at 100H and 10kH, two low-frequency turning frequencies of approximately 100Hz can be calculated Double
  range, that is, L2 - 100№×21g=100×4=400Hz. The high-frequency turning frequency point can also be calculated: fHI=
10kHz 2~=2500Hz.
    (3) Select the control potentiometer: Considering that the input impedance of the TL082 operational amplifier is very high, the resistance values ​​of E) l and RPz can be appropriately
selected, and RPi=RP2=500kn can be selected. It is better to choose a Z-shaped potentiometer.