Electronically controlled variable semiconductor resistor

摘要

An electronically controlled variable semiconductor resistor having a three layer construction of either an NPN-type or a PNP-type which is similar to that of a bipolar transistor and basically using the base region and collector region of the transistor as a variable resistor having its resistance value controlled by varying its emitter current. The conductivity of the base region adjoining the emitter region and that of the collector region opposite the emitter region across the base region are modulated largely by minority carriers injected into the base region from the emitter. The carrier density at each emitter, base or collector region is reasonably controlled so as to thereby make it possible to obtain a variable resistor whose resistance value changes about in an inverse proportion to the emitter current and the electrode of proper construction is designed to allow the control signal component for controlling the emitter current not to appear at both ends of the resistor electrode at the resistor.