The MCR225FP/D is a reverse blocking thyristor designed primarily for half-wave ac control applications such as motor controls, heating controls and power supply crowbar circuits. The thyristor has the following features: Glass passivated junctions with center gate fire for greater parameter uniformity and stability; Small, rugged, Thermowatt constructed for low thermal resistance, high heat dissipation and durability; Blocking voltage to 800 volts; 300 A surge current capability; Insulated package simplifies mounting.