KST42 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: 0.35 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 KST42 transistor is marked as "1D".The complementary PNP transistor to the KST42 is the KST92.You can replace the KST42 with the MMBTA42, PBHV8540T or STR1550.