BC548

Single Bipolar Transistors Overview

The Fairchild Semiconductor BC548 is a small signal NPN silicon bipolar junction transistor designed for general-purpose amplification and switching applications. It features an epitaxial planar construction housed in a lead-free TO-92 package. The device supports a maximum collector current of 0.1 A and a collector-emitter breakdown voltage of 30 V. Key electrical characteristics include a minimum DC current gain (hFE) of 110 at specified test conditions, a transition frequency of 300 MHz, and a maximum power dissipation of 625 mW. It operates within a junction temperature range of -55°C to 150°C.

Single Bipolar Transistors Feature Summary

• Epitaxial planar silicon construction for reliable small-signal performance
• Lead-free packaging compliant with environmental directives
• High-voltage capability suitable for general-purpose amplifier circuits

Single Bipolar Transistors Applications

• General-purpose amplifier circuits
• Electronic switching applications
• Low-noise signal processing stages

Single Bipolar Transistors Procurement Notes

Verify the specific suffix code on the component marking to confirm the exact hFE binning grade, as this determines the minimum current gain specification. Ensure the procurement documentation explicitly states lead-free compliance if RoHS requirements are mandatory for the assembly process. Cross-reference the manufacturer datasheet for precise thermal derating curves relevant to the intended operating environment.

Single Bipolar Transistors Selection Notes

Select the BC548 when a standard NPN transistor with 30V breakdown and 100mA continuous current capacity is required. Consider alternative suffixes if higher current gain or different voltage ratings are needed. Verify that the TO-92 through-hole package fits the PCB layout constraints. Confirm that the 625mW power dissipation rating meets the thermal requirements of the specific circuit design under worst-case operating conditions.

Single Bipolar Transistors Part Context

The BC548 belongs to a widely recognized family of NPN general-purpose transistors produced by multiple manufacturers. It serves as the NPN counterpart to the PNP BC558 device. This series is commonly used in educational kits and consumer electronics due to its availability and standardized pinout. The component represents a legacy but still prevalent solution for low-power discrete logic and analog interface tasks.

Single Bipolar Transistors Replacement Considerations

• BC548A
• BC548B
• BC548C

Single Bipolar Transistors FAQ

What is the difference between BC548A, B, and C variants?

The suffix letters indicate different bins of DC current gain (hFE). The 'A' variant has the lowest minimum gain, while 'C' offers the highest. The fundamental electrical ratings such as voltage and current remain identical across these variants.

Is the BC548 suitable for high-frequency RF applications?

While it has a transition frequency of 300 MHz, it is primarily classified as a general-purpose amplifier. For dedicated RF applications requiring lower noise figures, the BC549 or BC550 series are typically more appropriate choices.