BC557B

The BC557B is a general-purpose PNP bipolar junction transistor. It is part of the BC557 family, which includes variants like BC557A and BC557C, differing primarily in their current gain (hFE) ranges. This transistor is designed for small-signal applications and is commonly found in a wide array of electronic circuits.

It features a complementary NPN counterpart, the BC558B. The BC557B is characterized by its moderate current handling capability and relatively low noise. Its typical applications include amplification, switching, and as a driver stage in various audio and general electronics projects. The transistor is housed in a TO-92 package, a small plastic enclosure with three leads, making it suitable for through-hole mounting on printed circuit boards.

Key electrical parameters for the BC557B include a maximum collector current of 100 mA and a maximum collector-emitter voltage of 45 V. The DC current gain (hFE) for the 'B' variant typically ranges from 200 to 450 at a collector current of 2 mA. Its operating temperature range is generally from -55°C to +150°C. The BC557B is widely available and cost-effective, contributing to its popularity among hobbyists and in commercial product design.