BC259B Bipolar Transistor

• Type: PNP
• Collector-Emitter Voltage, max: -20 V
• Collector-Base Voltage, max: -25 V
• Emitter-Base Voltage, max: -5 V
• Collector Current − Continuous, max: -0.1 A
• Collector Dissipation: 0.3 W
• DC Current Gain (h_fe): 200 to 450
• Transition Frequency, min: 180 MHz
• Noise Figure, max: 1.2 dB
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-92

The BC259B is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, collector, and base leads.
Here is an image showing the pin diagram of this transistor.The BC259B transistor can have a current gain of 200 to 450. The gain of the BC259 will be in the range from 110 to 800, for the BC259A it will be in the range from 110 to 220, for the BC259C it will be in the range from 420 to 800.The complementary NPN transistor to the BC259B is the BC169B.You can replace the BC259B with the 2N4059, 2N4062, 2N4953, 2N4954, 2SA1031, 2SA1282A, 2SA1300, 2SA608, 2SA628, 2SB598, 2SB698, BC258, BC258B, MPS3638, MPS3638A, PN3638 or PN3638A.