2N6123 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 80 V
• Collector-Base Voltage, max: 80 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 4 A
• Collector Dissipation: 40 W
• DC Current Gain (h_fe): 25 to 80
• 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 2N6123 is the 2N6126.You can replace the 2N6123 with the 2N6100, 2N6101, 2N6131, 2N6473, 2N6474, 2N6488, 2N6488G, 2SC2075, 2SD1274, 2SD1274A, 2SD1274B, 2SD772, 2SD792, 2SD823, BD709, BD711, BD743B, BD743C, BD909, BD911, BDT93, BDT93F, BDT95, BDT95F, MJE5180, MJE5181, MJE5182, MJF3055, MJF3055G, NTE291, TIP41D, TIP41E, TIP41F, TIP42D, TIP42E or TIP42F.