BF420 Bipolar Transistor

• Type: NPN
• Collector-Emitter Voltage, max: 300 V
• Collector-Base Voltage, max: 300 V
• Emitter-Base Voltage, max: 5 V
• Collector Current − Continuous, max: 0.05 A
• Collector Dissipation: 0.8 W
• DC Current Gain (h_fe): 50
• Transition Frequency, min: 60 MHz
• Operating and Storage Junction Temperature Range: -55 to +150 °C
• Package: TO-92

The BF420 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, collector, and base leads.
Here is an image showing the pin diagram of this transistor.The complementary PNP transistor to the BF420 is the BF421.The BF620 (SOT-89) and BF820 (SOT-23) is the SMD version of the BF420 transistor. These transistors are of the same type, have similar parameters and are designed for surface mounting.You can replace the BF420 with the 2SC1473AQ, 2SC1473AR, 2SC1573A-Q, 2SC1573A-R, 2SC1573B-Q, 2SC1573B-R, 2SC2271-D, 2SC2271-E, 2SC2551-O, 2SC3468-D, 2SC3468-E, 2SC3468-F, 2SC3941-Q, 2SC3941-R, 2SC5201, KSC1506-O, KSC1506-Y, KSC2330O or KSC2330Y.