The 2N4392-E3 is a small signal NPN bi-polar transistor from Vishay’s semiconductor division. This is a standard general purpose transistor with a Vcb maximum voltage of 30 volts, an Ic max current of 500mA, a hFE minimum gain of 100 and a Pd maximum power dissipation of 500mW. It has a low operating temperature range of -55C to 150C, is housed in a small SOT-23 package and has fast switching times for quick response.