This part is a kind of semiconductor called DTC124E.

Function of this product has NPN SILICON BIAS RESISTOR TRANSISTOR.

Manufacturers : ON Semiconductor

Image and pinout :

Some of the text within the PDF file :

DTC114E Series Preferred Devices Bias Resistor Transistor NPN Silicon Surface Mount Transistor with Monolithic Bias Resistor Network This new series of digital transistors is designed to replace a single device and its external resistor bias network. The BRT (Bias Resistor Transistor) contains a single transistor with a monolithic bias network consisting of two resistors; a series base resistor and a base–emitter resistor. The BRT eliminates these individual components by integrating them into a single device. The use of a BRT can reduce both system cost and board space. The device is housed in the TO–92 package which is designed for through hole applications. http://onsemi.com NPN SILICON BIAS RESISTOR TRANSISTOR PIN 3 COLLECTOR (OUTPUT) MAXIMUM RATINGS (TA = 25°C unless otherwise [ ... ]

DTC124E PDF Datasheet Download