This part is a kind of semiconductor called BDY55.

Function of this product has SILICON POWER TRANSISTOR.

Manufacturers : SavantIC

Image and pinout :

Some of the text within the PDF file :

SavantIC Semiconductor Product Specification Silicon NPN Power Transistors BDY55 DESCRIPTION ·With TO-3 package ·High current capability ·Fast switching speed APPLICATIONS ·LF large signal power amplification. PINNING (See Fig.2) PIN 1 2 3 Base Emitter Collector Fig.1 simplified outline (TO-3) and symbol DESCRIPTION Absolute maximum ratings(Ta=25 ) SYMBOL VCBO VCEO VEBO IC IB PT Tj Tstg PARAMETER Collector-base voltage Collector-emitter voltage Emitter-base voltage Collector current Base current Total power dissipation Junction temperature Storage temperature TC=25 CONDITIONS Open emitter Open base Open collector VALUE 100 60 7 15 7 117 200 -65~200 UNIT V V V A A W THERMAL CHARACTERISTICS SYMBOL Rth j-c PARAMETER Thermal resistance from junction to case MAX 1 [ ... ]

BDY55 PDF Datasheet Download