This part is a kind of semiconductor called BT137.

Function of this product has Triacs.

Manufacturers : NXP

Image and pinout :

Some of the text within the PDF file :

Philips Semiconductors Product specification Triacs BT137 series GENERAL DESCRIPTION Glass passivated triacs in a plastic envelope, intended for use in applications requiring high bidirectional transient and blocking voltage capability and high thermal cycling performance. Typical applications include motor control, industrial and domestic lighting, heating and static switching. QUICK REFERENCE DATA SYMBOL PARAMETER BT137BT137BT137Repetitive peak off-state voltages RMS on-state current Non-repetitive peak on-state current MAX. MAX. MAX. UNIT 500 500F 500G 500 8 65 600 600F 600G 600 8 65 800 800F 800G 800 8 65 VDRM IT(RMS) ITSM V A A PINNING - TO220AB PIN 1 2 3 tab DESCRIPTION main terminal 1 PIN CONFIGURATION tab SYMBOL T2 main terminal 2 gate main terminal 2 1 23 T1 G LIMITI [ ... ]

BT137 PDF Datasheet Download