2SB1251 Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -90 V
• Collector-Base Voltage, max: -110 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -4 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 5000 to 30000
• Transition Frequency, min: 20 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-220F

Here is an image showing the pin diagram of this transistor.The 2SB1251 transistor can have a current gain of 5000 to 30000. The gain of the 2SB1251-P will be in the range from 5000 to 15000, for the 2SB1251-Q it will be in the range from 8000 to 30000.Sometimes the "2S" prefix is not marked on the package - the 2SB1251 might only be marked "B1251".The complementary NPN transistor to the 2SB1251 is the 2SD1891.You can replace the 2SB1251 with the 2SB1227, 2SB1228, 2SB1252, 2SB1481, 2SB1626, 2SB885, 2SB886, BD244C, BD540C, BD544C, BD546C, BD650, BD652, BD802, BD902, BD954, BD956, BDT60B, BDT60C, BDT62B, BDT62C, BDT64B, BDT64C, BDT86, BDT86F, BDT88, BDT88F, BDW47, BDW47G, BDW48, BDX34C, BDX34CG, BDX34D, BDX54C, BDX54CG, BDX54D, BDX54E, BDX54F, MJE15029, MJE15029G, MJE15031, MJE15031G, MJF127, MJF127G, MJF15031, MJF15031G, TIP127, TIP127G or TIP147T.