2SB1055 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -120 V
• Collector-Base Voltage, max: -120 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -6 A
• Collector Dissipation: 70 W
• DC Current Gain (h_fe): 40 to 200
• Transition Frequency, min: 20 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-3PF

Here is an image showing the pin diagram of this transistor.The 2SB1055 transistor can have a current gain of 40 to 200. The gain of the 2SB1055-P will be in the range from 100 to 200, for the 2SB1055-Q it will be in the range from 60 to 120, for the 2SB1055-R it will be in the range from 40 to 80.Sometimes the "2S" prefix is not marked on the package - the 2SB1055 might only be marked "B1055".The complementary NPN transistor to the 2SB1055 is the 2SD1486.The BDP956 (SOT-223) is the SMD version of the 2SB1055 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2SB1055 with the 2SB1056 or 2SB1057.