The 2N3906 is a common PNP bipolar junction transistor used for general purpose low-power amplifying or switching applications. Compared to the general run of silicon transistors, it is designed for low current and power and medium voltage, and can operate at moderately high speeds. The type was registered by Motorola Semiconductor in the mid-sixties, together with the complementary NPN type 2N3904, and represented a significant performance/cost improvement, with the plastic TO-92 case replacing metal cans.
It is a 200-milliamp, 40-volt, 300-milliwatt transistor with an Ft of 250 MHz, with a beta of at least 100[1].