Littelfuse Q Series Switching Thyristors are bidirectional, solid-state protection devices designed to handle loads from 0.8A to 40ARMS with 10mA, 25mA, and 50mA IGT in operating Quadrants I, II, III, and IV. Littelfuse developed the Q Series Switching Thyristors for a wide range of AC applications to control AC power either through full-cycle switching or phase control of current to the load element. Q Series devices are rated to block voltage in the OFF condition from 200V minimum with selected products capable of 1000V operation. Internally-constructed, isolated packages are available for ease of heat sinking with highest isolation voltage.