1600 V phase control thyristor disc Phase Control Thyristor 1600 V, 1500 A with 75 mm diameter and a height of 26 mm assembled in high reliable, robust and hermetic sealed ceramic housings. The T1900N prime disc is specially optimized for UPS-Bypass applications and offers the highest current capability in the market.The T1900N16TOF prime disc is specially optimized for UPS-Bypass applications and offers the highest current capability in the market.