This part is a kind of semiconductor called BDX34B.

Function of this product has DARLINGTON COMPLEMENTARY SILICON POWER TRANSISTORS.

Manufacturers : ON Semiconductor

Image and pinout :

Some of the text within the PDF file :

BDX33B, BDX33C (NPN) BDX34B, BDX34C (PNP) Darlington Complementary Silicon Power Transistors These devices are designed for general purpose and low speed switching applications. Features • High DC Current Gain − hFE = 2500 (typ.) at IC = 4.0 • Collector−Emitter Sustaining Voltage at 100 mAdc VCEO(sus) = 80 Vdc (min) − BDX33B, BDX334B = 100 Vdc (min) − BDX33C, BDX334C • Low Collector−Emitter Saturation Voltage VCE(sat) = 2.5 Vdc (max) at IC = 3.0 Adc − BDX33B, 33C/34B, 34C • Monolithic Construction with Build−In Base−Emitter Shunt Resistors • These Devices are Pb−Free and are RoHS Compliant* MAXIMUM RATINGS Rating Collector−Emitter Voltage BDX33B, BDX34B BDX33C, BDX34C Symbol VCEO Value 80 100 Unit Vdc Collector−Base Voltage BDX33B, BDX34B BDX33C, BDX34 [ ... ]

BDX34B PDF Datasheet Download