2SB1057-Q Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -150 V
• Collector-Base Voltage, max: -150 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -9 A
• Collector Dissipation: 100 W
• DC Current Gain (h_fe): 60 to 120
• 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 2SB1057-Q transistor can have a current gain of 60 to 120. The gain of the 2SB1057 will be in the range from 40 to 200, for the 2SB1057-P it will be in the range from 100 to 200, for the 2SB1057-R it will be in the range from 40 to 80.Sometimes the "2S" prefix is not marked on the package - the 2SB1057-Q might only be marked "B1057-Q".You can replace the 2SB1057-Q with the 2SA1673, 2SA1860, 2SA1987, 2SB1160, 2SB1160-Q, 2SB1161 or 2SB1161-Q.