BC171 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 45 V
• Collector-Base Voltage, max: 50 V
• Emitter-Base Voltage, max: 6 V
• Collector Current − Continuous, max: 0.1 A
• Collector Dissipation: 0.3 W
• DC Current Gain (h_fe): 110 to 450
• Noise Figure, max: 10 dB
• Operating and Storage Junction Temperature Range: -65 to +150 °C
• Package: TO-92

The BC171 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 collector, base, and emitter leads.
Here is an image showing the pin diagram of this transistor.The BC171 transistor can have a current gain of 110 to 450. The gain of the BC171A will be in the range from 110 to 220, for the BC171B it will be in the range from 200 to 450.The 2SC1623 (SOT-23), BC847 (SOT-23), BC847W (SOT-323), BC850 (SOT-23), BC850W (SOT-323) and KSC1623 (SOT-23) is the SMD version of the BC171 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the BC171 with the BC337, BC445, BC447, BC546, BC547 or BC550.