BD791 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 100 V
• Collector-Base Voltage, max: 100 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 BD791 is the BD792.The BDP953 (SOT-223) is the SMD version of the BD791 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the BD791 with the MJE244.