This part is a kind of semiconductor called BD131.

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 BD131 DESCRIPTION ·Complement to type BD132 ·With TO-126 package ·High current (Max: 3A) ·Low voltage (Max: 45V) APPLICATIONS ·For general purpose power applications PINNING PIN 1 2 3 DESCRIPTION Emitter Collector;connected to mounting base Base Absolute maximum ratings (Ta=25 ) SYMBOL VCBO VCEO VEBO IC ICM IBM PT Tj Tstg PARAMETER Collector-base voltage Collector-emitter voltage Emitter -base voltage Collector current (DC) Collector current-Peak Base current-Peak Total power dissipation Junction temperature Storage temperature Tmb660 Open emitter Open base Open collector CONDITIONS VALUE 70 45 6 3 6 0.5 15 150 -65~150 UNIT V V V A A A W THERMAL CHARACTERISTICS SYMBOL Rth j-a Rth j-mb [ ... ]

BD131 PDF Datasheet Download