This part is a kind of semiconductor called D1804.

Function of this product has 2SD1804.

Manufacturers : Sanyo Semicon Device

Image and pinout :

Some of the text within the PDF file :

Ordering number:ENN2086B PNP/NPN Epitaxial Planar Silicon Transistors 2SB1204/2SD1804 High-Current Switching Applications Applications Æ Relay drivers, high-speed inverters, converters, and other general high-current switching applications. Package Dimensions unit:mm 2045B [2SB1204/2SD1804] 1.5 Features Æ Low collector-to-emitter saturation voltage. Æ High current and high fT. Æ Excellent linearity of hFE. Æ Fast switching time. Æ Small and slim package making it easy to make 2SB1204/2SD1804-applied sets smaller. 6.5 5.0 4 2.3 0.5 0.85 0.7 0.8 1.6 5.5 7.0 1.2 7.5 0.6 1 2 3 0.5 2.3 2.3 1 : Base 2 : Collector 3 : Emitter 4 : Collector SANYO : TP unit:mm 2044B [2SB1204/2SD1804] 6.5 5.0 4 2.3 1.5 0.5 5.5 7.0 0.85 1 0.6 0.5 0.8 2 3 2.5 1.2 0 to 0.2 1.2 2.3 2 [ ... ]

D1804 PDF Datasheet Download