2N5551 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 160 V
• Collector-Base Voltage, max: 180 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 0.6 A
• Collector Dissipation: 0.625 W
• DC Current Gain (h_fe): 80 to 250
• Transition Frequency, min: 100 MHz
• Noise Figure, max: 8 dB
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-92

The 2N5551 is manufactured in a plastic TO-92 case. When looking at the flat side with the leads pointed downward, the three leads emerging from the transistor are, from left to right, the emitter, base, and collector leads. The 2N5551C transistor (with suffix "C") is the center collector version of the 2N5551.
Here is an image showing the pin diagram of this transistor.The complementary PNP transistor to the 2N5551 is the 2N5401.The 2N5551S (SOT-23), DXT5551 (SOT-89), DZT5551 (SOT-223), KST43 (SOT-23), KST5551 (SOT-23), MMBT5551 (SOT-23) and PMBT5551 (SOT-23) is the SMD version of the 2N5551 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the 2N5551 with the 2N5551G, 2N5833 or NTE194.The 2N5551G transistor is the lead-free version of the 2N5551.