2N2904

High-speed PNP silicon planar switching and amplification transistor housed in a medium-sized metal TO-39 can, designed to handle moderate current loads as the complementary match to the NPN 2N2219. Equivalents: 2N2905, BSV15, NTE129. Real-Life Examples: Mid-1970s consumer audio output driver boards, switching power supply regulation loops, and industrial relay actuator control blocks.