PURPOSE: To curtail the number of elements by expanding the logical amplitude of a gate circuit for contrast and setting and deciding the reference voltage of an external gate circuit to contrast these levels and a reference voltage to the vicinity of the center of a high level and an intermediate level.

CONSTITUTION: Resistances RC5 and RC6 for a collector are made 1.2times as much as the resistance value for a conventional collector and a logical amplitude is expanded. A circuit is connected to outputs C and D, a reference voltage VREFE is set to the inverse of 0.93V, and thus, an intermediate level is considered as a low level and operated. Consequently, the EX-OR signal of input signals A and B can be obtained to the collector output of a transistor TR 11. Thus, the EX-OR circuit can be composed of five transistors for an internal gate, five resistances for an internal gate, four transistors for an external gate and three resistances.