This part is a kind of semiconductor called MD1803DFX.

Function of this product has High voltage NPN Power transistor.

Manufacturers : ST Microelectronics

Image and pinout :

Some of the text within the PDF file :

MD1803DFX High voltage NPN Power transistor for standard definition CRT display Features ■ ■ ■ ■ ■ ■ ■ State-of-the-art technology: – Diffused collector “enhanced generation” More stable performance versus operating temperature variation Low base drive requirement Tighter hFE range at operating collector current Fully insulated power package U.L. compliant Integrated free wheeling diode In compliance with the 2002/93/EC european directive 1 3 2 ISOWATT218FX Applications ■ Internal schematic diagram Horizontal deflection output for TV Description The MD1803DFX is manufactured using Diffused Collector in Planar Technology adopting new and enhanced high voltage structure. The new MD product series show improved silicon efficiency bringing updat [ ... ]

MD1803DFX PDF Datasheet Download