2SD401 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 150 V
• Collector-Base Voltage, max: 200 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 2 A
• Collector Dissipation: 25 W
• DC Current Gain (h_fe): 40 to 400
• Transition Frequency, min: 5 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-220

Here is an image showing the pin diagram of this transistor.The 2SD401 transistor can have a current gain of 40 to 400. The gain of the 2SD401-G will be in the range from 200 to 400, for the 2SD401-O it will be in the range from 70 to 140, for the 2SD401-R it will be in the range from 40 to 80, for the 2SD401-Y it will be in the range from 120 to 240.Sometimes the "2S" prefix is not marked on the package - the 2SD401 might only be marked "D401".The complementary PNP transistor to the 2SD401 is the 2SB546.You can replace the 2SD401 with the 2SD402, 2SD772, 2SD772A, 2SD772B, 2SD792, 2SD792A, 2SD792B, MJE15030, MJE15030G, MJF15030, MJF15030G, TIP41F or TIP42F.