This part is a kind of semiconductor called 2N4125.

Function of this product has Silicon PNP Transistor.

Manufacturers : NTE

Image and pinout :

Some of the text within the PDF file :

2N4125 & 2N4126 Silicon PNP Transistor Audio Amplifier, Switch TO92 Type Package Absolute Maximum Ratings: Collector−Emitter 2N4125 . . Voltage, V. .C.E.O. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V 2N4126 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25V Collector−Base 2N4125 Voltage, V. .C.B.O. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30V 2N4126 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [ ... ]

2N4125 PDF Datasheet Download