2SB557 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: -8 A
• Collector Dissipation: 80 W
• DC Current Gain (h_fe): 40 to 140
• Transition Frequency, min: 7 MHz
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: TO-3

Here is an image showing the pin diagram of this transistor.The 2SB557 transistor can have a current gain of 40 to 140. The gain of the 2SB557-O will be in the range from 70 to 140, for the 2SB557-R it will be in the range from 40 to 80.Sometimes the "2S" prefix is not marked on the package - the 2SB557 might only be marked "B557".The complementary NPN transistor to the 2SB557 is the 2SD427.You can replace the 2SB557 with the 2SA1007, 2SA1007A, 2SA1041, 2SA1043, 2SA679, 2SA745A, 2SA747, 2SA747A, 2SA908, 2SA909, 2SB554, 2SB555, 2SB556, 2SB600, 2SB696, 2SB697, 2SB697K, 2SB705, 2SB705A, 2SB705B, 2SB706, 2SB706A, 2SB723, MJ15002, MJ15002G, MJ15004 or MJ15004G.