The 2N3054 from NTE is a single Hfe, NPN, Bipolar (BJT) transistor housed in a TO-202 package that can handle currents of up to 4 Amp and power dissipation of upto 25 Watts. It has a maximum collector-emitter voltage of 55V and can operate at a maximum frequency of 3MHz. The device's Hfe (DC current gain) ranges from 100 to 600. As with most transistors, it is able to be used as an amplifier, switch and a low noise generator. This popular device is used in many industrial and consumer products, including amplifiers, power supplies and switching circuits.