Investigation of the saturation effect of the drain current of a field-effect transistor with series-connected channels

Abstract

The results of the research of dynamic modulation of the field-effect transistor’s channel with a second field-effect transistor series connected to the source of the first one acting as a dual-gate by controlled changes in the voltage distribution in auxiliary control p-n-junction are given. Comparison of the initial drain characteristics with characteristics of the field-effect transistor controlled by voltage drops in the channel of the second transistor showed that the proposed process of saturation of the drain current due to the expansion of the space charge across the width of the gate is confirmed, providing a marked saturation of the drain current and high dynamic resistance. It was shown experimentally that the gain of the field-effect transistor is an order of magnitude higher (70) than traditional inclusions of common-source (5) or with a dynamic load. The gain becomes a function of the reverse voltage, and maximum values   are achieved with reverse voltage equal to half the cut-off voltage. This is due to the fact that both channels of the transistor are modulated effectively until the saturation voltage of the drain current. The experimental method for rapid determination of the channel resistance of the field-effect transistor is proposed.