2N3440 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 250 V
• Collector-Base Voltage, max: 300 V
• Emitter-Base Voltage, max: 7 V
• Collector Current − Continuous, max: 1 A
• Collector Dissipation: 1 W
• DC Current Gain (h_fe): 40 to 160
• Transition Frequency, min: 15 MHz
• Operating and Storage Junction Temperature Range: -65 to +200 °C
• Package: TO-39

Here is an image showing the pin diagram of this transistor.The KST42 (SOT-23), MMBTA42 (SOT-23) and PZTA42 (SOT-223) is the SMD version of the 2N3440 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2N3440 with the 2N3439 or NTE396.