Formalizing Implicatures Using Extended Logic Programming

A light-activated bi-directional thyristor of a planar structure having P type base layers for first and second thyristors in a light receiving section, the P type base layers being separated from each other by an N type base layer. An N type emitter layer is formed at that part of the P type base layer for the second thyristor which is located on the side of the light receiving section. A first auxiliary electrode is laminated to the N type emitter layer to form an amplifying gate section. A second auxiliary electrode is formed on the P type base layer which is located opposite the light receiving section. On-current of the amplifying gate section is supplied to a shorted emitter in the second thyristor, through a connector for electrically connecting the first and second auxiliary electrodes.