This part is a kind of semiconductor called 2SD2101.

Function of this product has Silicon NPN Triple Diffused.

Manufacturers : Hitachi Semiconductor

Image and pinout :

Some of the text within the PDF file :

2SD2101 Silicon NPN Triple Diffused Application Low frequency power amplifier Outline TO-220FM 2 1 1. Base 2. Collector 3. Emitter 12 3 3 kΩ (Typ) 150 Ω (Typ) 3 2SD2101 Absolute Maximum Ratings (Ta = 25°C) Item Collector to base voltage Collector to emitter voltage Emitter to base voltage Collector current Collector peak current Collector power dissipation Symbol VCBO VCEO VEBO IC I C(peak) PC PC * Junction temperature Storage temperature Note: 1. Value at TC = 25°C. Tj Tstg 1 Rating 200 200 7 10 15 2 30 150 –55 to +150 Unit V V V A A W °C °C Electrical Characteristics (Ta = 25°C) Item Collector to base breakdown voltage Symbol V(BR)CBO Min 200 200 170 7 1500 Typ Max 10 50 1.5 3.0 [ ... ]

2SD2101 PDF Datasheet Download