2SB857 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -50 V
• Collector-Base Voltage, max: -70 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -4 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 60 to 320
• Transition Frequency, min: 15 MHz
• Operating and Storage Junction Temperature Range: -45 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.The 2SB857 transistor can have a current gain of 60 to 320. The gain of the 2SB857-B will be in the range from 60 to 120, for the 2SB857-C it will be in the range from 100 to 200, for the 2SB857-D it will be in the range from 160 to 320.Sometimes the "2S" prefix is not marked on the package - the 2SB857 might only be marked "B857".The complementary NPN transistor to the 2SB857 is the 2SD1133.You can replace the 2SB857 with the 2SA1262, 2SA1488, 2SA1488A, 2SA1634, 2SA1635, 2SA770, 2SA771, 2SB633, 2SB858, BD204, BD244A, BD244B, BD244C, BD304, BD536, BD538, BD540A, BD540B, BD540C, BD544A, BD544B, BD544C, BD546A, BD546B, BD546C, BD798, BD800, BD802, BD808, BD810, BD950, BD952, BD954, BDT82, BDT82F, BDT84, BDT84F, BDT86, BDT86F, BDX78, D44C10, D44C11, D44C12, D44C7, D44C8, D44C9, D45C10, D45C11, D45C12, D45C7, D45C8, D45C9, D45H11, D45H11FP or D45H8.