This part is a kind of semiconductor called BTB04.

Function of this product has Triacs.

Manufacturers : Inchange Semiconductor

Image and pinout :

Some of the text within the PDF file :

INCHANGE Semiconductor isc Triacs isc Product Specification BTB04 T/D/S/A FEATURES ·With TO-220AB non insulated package ·Suitables for general purpose applications where gate high sensitivity is required. Application on 4Q such as phase control and static switching. ABSOLUTE MAXIMUM RATINGS(Ta=25℃) SYMBOL PARAMETER IT(RMS) ITSM Tj Tstg Rth(j-c) Rth(j-a) RMS on-state current (full sine wave)Tj=95℃ Non-repetitive peak on-state current tp=10ms Operating junction temperature Storage temperature Thermal resistance, junction to case Thermal resistance, junction to ambient MIN UNIT 4A 40 A 110 ℃ -45~150 ℃ 3.2 ℃/W 60 ℃/W SYMBOL PARAMETER VDRM VRRM Repetitive peak off-state voltage Repetitive peak reverse voltage 400T/D/S/A 600T/D/S/A 700T/D/S/A UNIT 400 600 700 V 400 600 [ ... ]

BTB04 PDF Datasheet Download