In this research, the challenges of variable interest boosters are categorized. Then we will explain the introduction of the important and dominant features in variable gain amplifiers, which are responsible for providing linear decibel gain changes, and after categorizing these features, we will implement the special pseudo-exponential mathematical model introduced in a circuit. Low noise amplifiers are used to record neural potentials in many medical applications. Recording the action potential of signals outside the body is one of the most challenging parts. They include a frequency range of 0.1 Hz to 10 kHz and an amplitude of 50 μV to 500 μV with a noise level of 5 μV to 10 μV. These signals include the DC signal around 500 mv, which is caused by the interactions of the electrode electrolyte. The range of small signals, high frequency range and large DC value are one of the major challenges in the design of neural signal recording amplifiers.