BD789 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 80 V
• Collector-Base Voltage, max: 80 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 4 A
• Collector Dissipation: 15 W
• DC Current Gain (h_fe): 40 to 250
• Transition Frequency, min: 40 MHz
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: TO-126

Here is an image showing the pin diagram of this transistor.The complementary PNP transistor to the BD789 is the BD790.The BDP951 (SOT-223) is the SMD version of the BD789 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the BD789 with the BD791, MJE242 or MJE244.