The 2N3904 is a common NPN bipolar junction transistor used for general purpose low-power amplifying or switching applications. The type was registered by Motorola Semiconductor in the mid-sixties, together with the complementary PNP type 2N3906, and represented a significant performance/cost improvement, with the plastic TO-92 case replacing metal cans. It is designed for low current and power, medium voltage, and can operate at moderately high speeds. This transistor is low cost, widely available and sufficiently robust to be of use by experimenters. When looking at the flat side with the leads pointed downward, the three wires emerging from the bottom are connected to, left to right, the emitter, the base and the collector. Some manufacturers mark "EBC" on the molded part, but all are required to have those connections for a part which is a "2N3904".
