2SC3851 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 60 V
• Collector-Base Voltage, max: 80 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 4 A
• Collector Dissipation: 25 W
• DC Current Gain (h_fe): 40 to 320
• Transition Frequency, min: 15 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-220F

Here is an image showing the pin diagram of this transistor.Sometimes the "2S" prefix is not marked on the package - the 2SC3851 might only be marked "C3851".The complementary PNP transistor to the 2SC3851 is the 2SA1488.You can replace the 2SC3851 with the 2SC1826, 2SC1985, 2SC1986, 2SC2075, 2SC3179, 2SC3851A, 2SD1274, 2SD1274A, 2SD1274B, 2SD613, 2SD823, BD203, BD243A, BD243B, BD243C, BD303, BD535, BD537, BD539A, BD539B, BD539C, BD539D, BD797, BD799, BD801, BD807, BD809, BD949, BD951, BD953, BD955, BDT81, BDT81F, BDT83, BDT83F, BDT85, BDT85F, BDT87, BDT87F, BDX77, MJE15028, MJE15028G, TIP41D or TIP42D.