MMBTA42 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 300 V
• Collector-Base Voltage, max: 300 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 0.5 A
• Collector Dissipation: 0.25 W
• DC Current Gain (h_fe): 40
• Transition Frequency, min: 50 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: SOT-23

Here is an image showing the pin diagram of this transistor.The MMBTA42 transistor is marked as "1D".The complementary PNP transistor to the MMBTA42 is the MMBTA92.You can replace the MMBTA42 with the KST42, PBHV8540T or STR1550.