BC547B

The BC547B is a popular NPN bipolar junction transistor (BJT) commonly used in electronic circuits for amplification and switching applications. Manufactured by various semiconductor companies, including Fairchild Semiconductor, it belongs to the 2N3904 series and is part of the BC54x family, which features similar transistors with slight variations in gain and other parameters.

The BC547B is characterized by its low saturation voltage, moderate gain (hFE typically ranging from 110 to 800 at a collector current of 10 mA), and a maximum collector current of 100 mA. It operates efficiently within a voltage range of up to 65 volts and is designed for general-purpose use in analog and digital circuits. The transistor is housed in a TO-92 plastic package, making it widely compatible with breadboarding and small-scale circuit designs.

Key specifications include a maximum collector-emitter voltage (VCEO) of 65V, a maximum collector current (IC) of 100 mA, and a power dissipation (PC) of 625 mW. The BC547B is often paired with complementary PNP transistors like the BC557B to form complementary symmetry circuits, such as class-A amplifiers or push-pull drivers.

Due to its reliability, availability, and performance, the BC547B is frequently used in audio amplifiers, signal conditioning circuits, motor drivers, and simple switching applications. Its low cost and widespread availability make it a preferred choice for hobbyists, students, and professionals alike. However, for high-power or high-frequency applications, alternative transistors with higher ratings may be required.