The 2N3904 is a common NPN bipolar junction transistor used for general-purpose low-power amplifying or switching applications. [1] [2] [3] It is designed for low current and power , medium voltage , and can operate at moderately high speeds.

NPN General Purpose Amplifier This device is designed as a general purpose amplifier and switch. The useful dynamic range extends to 100 mA as a switch and to 100 MHz as an amplifier. Absolute Maximum Ratings* T A = 25°C unless otherwise noted Advanced Semiconductor, Inc., supplies RF power transistors and microwave diodes, replacing transistors from Motorola, Philips, and SGS Thomson, and others, and microwave diodes from HP, M/A-COM, Alpha, and others.