Thyristors of one conductivity type formed as an array in a first semiconductor body are respectively connected in parallel with thyristors of the opposite conductivity type formed as an array in a second semiconductor body to produce an array of triacs. In each body the thyristors are separate except for a common anode or cathode region and terminal connection, and are formed in an epitaxial layer divided by PN junction isolation regions on a substrate of opposite conductivity type. The thyristors may be constructed to be triggered by gating signals of either polarity.