BDT31 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 40 V
• Collector-Base Voltage, max: 80 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 3 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 10 to 50
• Transition Frequency, min: 3 MHz
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.The complementary PNP transistor to the BDT31 is the BDT32.You can replace the BDT31 with the BDT31A, BDT31B, TIP31, TIP31A, TIP31AG, TIP31B, TIP31BG or TIP31G.