2SC521A Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 50 V
• Collector-Base Voltage, max: 70 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 7 A
• Collector Dissipation: 50 W
• DC Current Gain (h_fe): 30 to 300
• Transition Frequency, min: 10 MHz
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: TO-3

Here is an image showing the pin diagram of this transistor.Sometimes the "2S" prefix is not marked on the package - the 2SC521A might only be marked "C521A".The complementary PNP transistor to the 2SC521A is the 2SA658A.You can replace the 2SC521A with the 2SC1584, 2SC520A, BD315, BD317, KD502 or KD503.