View 2sc4031 datasheet:

Ordering number:EN2478B NPN Triple Diffused Planar Silicon Transistor 2SC4031 900V/20mA Switching Applications Features Package Dimensions · High breakdown voltage (VCEO min=900V). unit:mm · Small Output Capacitance (Cob typ=1.6pF). 2049C · Wide ASO (adoption of MBIT process). [2SC4031] · High reliability (adoption of HVP process). 10.2 4.5 1.3 1.2 0.8 0.4 1 2 3 1 : Base 2 : Collector 3 : Emitter 2.55 2.55 SANYO : TO-220MF Specifications Absolute Maximum Ratings at Ta = 25?C Parameter Symbol Conditions Ratings Unit Collector-to-Base Voltage VCBO 2000 V Collector-to-Emitter Voltage VCEO 900 V Emitter-to-Base Voltage VEBO 5 V Collector Current IC 20 mA Collector Current (Pulse) ICP 60 mA Collector Dissipation PC 1.65 W 1.2 W Tc=25?C Junction Temperature