is that the current paths leading to the triggering of the triac are very similar with a possible inversion of the current direction in the four quadrants further the turn on areas are the same in quadrants q 1 and q 2 on the one hand and in quadrants q 3 and q 4 on the other hand and the turn on areas in the four quadrants are close to one another as a result and as proved by experimentations the sensitivity is the same in all four quadrants no specific measures need to be taken to favor one quadrant over the others experimentations have shown that when the auxiliary gate thyristor triggers first this triggering is very rapidly followed by the triggering of the main thyristor and occurs close to the end of the branches of the u the provision of a significant penetration of the rear surface n region under the gate is thus not necessary which increases the immunity of the triac to dv dt parasitic triggerings thus comparative studies between the triac of fig2 a 2c and a prior art triac such as shown in fig1 a 1c show that the triac described herein turns on in all four quadrants with the same gate current as the current useful to.