2SD400D Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 25 V
• Collector-Base Voltage, max: 25 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 1 A
• Collector Dissipation: 0.9 W
• DC Current Gain (h_fe): 60 to 120
• Transition Frequency, min: 180 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 2SD400D transistor can have a current gain of 60 to 120. The gain of the 2SD400 will be in the range from 60 to 560, for the 2SD400E it will be in the range from 100 to 200, for the 2SD400F it will be in the range from 160 to 320, for the 2SD400G it will be in the range from 280 to 560.Sometimes the "2S" prefix is not marked on the package - the 2SD400D might only be marked "D400D".The complementary PNP transistor to the 2SD400D is the 2SB544D.You can replace the 2SD400D with the 2N5295, 2N5296, 2N6288, 2N6288G, 2N6289, 2N6290, 2N6290G, 2N6291, 2N6486, 2N6486G, 2SC1061, 2SC1061-B, 2SC1398, 2SC1418, 2SC1418-B, 2SC1419, 2SC1419-B, 2SC790, 2SD1133, 2SD1133-B, 2SD1444A, 2SD1444A-R, 2SD1762, 2SD1762D, 2SD234, 2SD235, 2SD325, 2SD325-D, 2SD330, 2SD330D, 2SD476, 2SD476-B, 2SD612, 2SD612-D, 2SD612K, 2SD612K-D, 2SD795, 2SD795-R, BD201, BD239, BD241, BD243, BD301, BD533, BD539, BD543, BD545, BD705, BD733, BD735, BD737, BD743, BD795, BD905, BD933, BD933F or BDT29.