2SC3951 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 70 V
• Collector-Base Voltage, max: 80 V
• Emitter-Base Voltage, max: 3 V
• Collector Current − Continuous, max: 0.3 A
• Collector Dissipation: 8 W
• DC Current Gain (h_fe): 40 to 320
• Transition Frequency, min: 600 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-126F

Here is an image showing the pin diagram of this transistor.The 2SC3951 transistor can have a current gain of 40 to 320. The gain of the 2SC3951-C will be in the range from 40 to 80, for the 2SC3951-D it will be in the range from 60 to 120, for the 2SC3951-E it will be in the range from 100 to 200, for the 2SC3951-F it will be in the range from 160 to 320.Sometimes the "2S" prefix is not marked on the package - the 2SC3951 might only be marked "C3951".The complementary PNP transistor to the 2SC3951 is the 2SA1536.You can replace the 2SC3951 with the 2SC3599, 2SC3952, 2SC3954, 2SD414, 2SD415, BD169, BD237, BD237G, BD379, MJE242, MJE244 or MJE722.