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Transistors are nonunilateral amplifying devices. The most important effects of internal feedback are reflected immittances and potential instability of amplifiers in certain frequency ranges. These phenomena are undesirable in many applications. Considering the various matrix representations of a two-terminal pair one can show that by connecting appropriate networks in a suitable manner to the active nonunilateral element, the internal feedback of the latter can be removed (neutralized). Several neutralized transistor arrangements have been investigated experimentally. The circuits are based on an analysis of the properties of transistor feedback parameters at "higher" frequencies. Neutralization throughout relatively wide bands of frequencies can be achieved using simple feedback arrangements. The maximum available power gain of transistor amplifiers is only moderately affected by neutralization.