2SD401-Y 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): 120 to 240
• 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-Y transistor can have a current gain of 120 to 240. The gain of the 2SD401 will be in the range from 40 to 400, for the 2SD401-G it 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.Sometimes the "2S" prefix is not marked on the package - the 2SD401-Y might only be marked "D401-Y".The complementary PNP transistor to the 2SD401-Y is the 2SB546-Y.You can replace the 2SD401-Y with the 2SC4381, 2SC4382, 2SC4883, 2SC4883A, 2SC5171, 2SD1138, 2SD1264, 2SD1264-P, 2SD1264A, 2SD1264A-P, 2SD402, 2SD772, 2SD772A, 2SD772B, 2SD792, 2SD792A, 2SD792B, KSD401, KSD401-Y, KTD2061, KTD2061Y, MJE15030, MJE15030G, MJE15032, MJE15032G, MJF15030, MJF15030G, TIP41F or TIP42F.