2SD401-O 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): 70 to 140
• 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-O transistor can have a current gain of 70 to 140. 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-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-O might only be marked "D401-O".The complementary PNP transistor to the 2SD401-O is the 2SB546-O.You can replace the 2SD401-O with the 2SC4381, 2SC4382, 2SC4883, 2SC4883A, 2SD1138, 2SD1264, 2SD1264-Q, 2SD1264A, 2SD1264A-Q, 2SD401A, 2SD402, 2SD610, 2SD772, 2SD772A, 2SD772B, 2SD792, 2SD792A, 2SD792B, FJP5200, FJPF5200, KTD2061, KTD2061O, MJE15030, MJE15030G, MJE15032, MJE15032G, MJF15030, MJF15030G, TIP41F or TIP42F.