2SD401A 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 200
• 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 2SD401A transistor can have a current gain of 40 to 200. The gain of the 2SD401A-K will be in the range from 100 to 200, for the 2SD401A-L it will be in the range from 60 to 120, for the 2SD401A-M it will be in the range from 40 to 80.Sometimes the "2S" prefix is not marked on the package - the 2SD401A might only be marked "D401A".The complementary PNP transistor to the 2SD401A is the 2SB546A.You can replace the 2SD401A with the 2SD401, 2SD402, 2SD610, 2SD772, 2SD772A, 2SD772B, 2SD792, 2SD792A, 2SD792B, MJE15030, MJE15030G, MJF15030, MJF15030G, TIP41F or TIP42F.