This part is a kind of semiconductor called DTC124E.

Function of this product has NPN DIGITAL TRANSISTOR.

Manufacturers : UTC

Image and pinout :

Some of the text within the PDF file :

UNISONIC TECHNOLOGIES CO., DTC124E NPN DIGITAL TRANSISTOR (BUILT-IN RESISTORS) FEATURES NPN EPITAXIAL SILICON TRANSISTOR *Built-in bias resistors enable the configuration of an inverter circuit without connecting external input resistors (see the equivalent circuit). *The bias resistors consist of thin-film resistors with complete isolation to allow positive biasing of the input They also have the advantage of almost completely eliminating parasitic effects. *Only the on / off conditions need to be set for operation, making device design easy. 2 1 3 EQUIVALENT CIRCUIT R1 IN R2 GND IN GND OUT OUT MARKING SOT-23 *Pb-free plating product number:DTC124EL CC4 PIN CONFIGURATION PIN NO. PIN NAME 1 GND 2 IN 3 OUT ORDERING INFORMATION Order Number Normal Lead free D [ ... ]

DTC124E PDF Datasheet Download