Progress in Signals and Telecommunication Engineering Simeon Kostadinov, Ivan Uzunov, Dobromir Gaydazhiev 11 1 2022 https://www.dline.info/pste/fulltext/v11n1/pstev11n1_3.pdf We have detailed the three versions of a current amplifier and each of them is realized with FETs having different channel length: 90nm, 45nm and 30 nm. Besides we have tested elementary characteristics and discussed, demonstrating the major benefit of the shortening of the channel length – extension of the frequency bandwidth. Then we have analysed the possibilities of the issues of the shorter channels length.