2SB1251-Q 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): 8000 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-Q transistor can have a current gain of 8000 to 30000. The gain of the 2SB1251 will be in the range from 5000 to 30000, for the 2SB1251-P it will be in the range from 5000 to 15000.Sometimes the "2S" prefix is not marked on the package - the 2SB1251-Q might only be marked "B1251-Q".The complementary NPN transistor to the 2SB1251-Q is the 2SD1891-Q.You can replace the 2SB1251-Q with the 2SB1227, 2SB1228, 2SB1252, 2SB1252-Q, 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.