This part is a kind of semiconductor called DK51.

Function of this product has NPN Silicon High Power Switching Transistor.

Manufacturers : Qunli Electric

Image and pinout :

Some of the text within the PDF file :

Shaanxi Qunli Electric Co., Ltd Add.:No. 1 Qunli Road,Baoji City,Shaanxi,China DK51 NPN Silicon High Power Switching Transistor Features: 1. Good switching character. Excellent capacity in anti-burnout. 2. Good temperature stability. Small saturation voltage drop. 3. Implementation of standards: GJB33A -97, QZJ840611A, QZJ840611 4. Use for high power switch circuit,switching voltage-stabilized sourcefy circuit. 5. Quality Class: JP, JT, JCT, GS, G, G+ TECHNICAL DATA: Parameter name Specifications Symbols Unit A B C D E FG Total Dissipation Ptot W 50 Max. Collector Current Junction Temperature Storage Temperature ICM A Tjm °C Tstg °C 10 175 -55~+175 Collector-Emitter Breakdown Voltage V(BR)CEO V 30 50 80 110 150 200 250 E-Base Breakdown Voltage V(BR)EBO V 5 Collector- Emi [ ... ]

DK51 PDF Datasheet Download