The BC337 is a general purpose NPN bipolar junction transistor (BJT). This transistor is inexpensive, widely available and robust enough to be used for experiments and electronics hobbyists. The complementary PNP transistor is the BC327. https://elecena.pl/product/27740195/opencircuit-bc337-npn-transistor-25-pcs 2025-01-23 https://elecena.pl/product/27740195/opencircuit-bc337-npn-transistor-25-pcs 2026-04-12