Electric filters are circuits that filter input-to-output signals based on the amount of signal input frequency. They are divided into active and passive filters according to the structure and according to the area of signal frequency transmission into: low-pass, high-pass, band-pass and band dam filters. In this paper, the Butterworth LP (low-pass) 6th order filter will be analyzed and realized based on a given transfer function. The filter analysis will be performed based on the normalized and denormalized frequency and time characteristics of the filter. At the same time, the normalized values of parameters and filter elements will be determined, on the basis of which the denormalization process will obtain the actual values of parameters and filter elements denormalized to a given cut-off frequency in order to realize the desired characteristics filter. Using the LTspice software package, a simulation of the Butterworth LP filter of the 6th order will be performed, which will obtain the appropriate frequency and time characteristics. Finally, a filter will be physically realized on the experimental plate in the laboratory and measurements will be made using a network analyzer to determine the accuracy of the realization of the Butterworth LP filter of the 6th order.