This part is a kind of semiconductor called SBL2040.

Function of this product has Schottky Barrier Rectifier.

Manufacturers : GME

Image and pinout :

Some of the text within the PDF file :

Production specification Schottky Barrier Rectifier SBL2030---SBL2060 FEATURES z Mwtal-Semiconductor Junction with Guardring. z Epitaxial Construction. Pb z Lead-free Low Forward Voltage Drop,Low Switching Losses. z High Surge Capability. z For Use in Low Voltage,High Frequency Inverters Free Wheeling,and Polarity Protection Applications. z The Plastic Material Carries U/L Recognition 94V-0. TO-220AC MAXIMUM RATING operating temperature range applies unless otherwise specified Symbol Parameter SBL 2030 SBL 2035 SBL 2040 SBL 2045 SBL 2050 SBL 2060 Unit VRRM Recurrent Peak Reverse Voltage 30 35 40 45 50 60 V VRMS RMS Reverse Voltage 21 25 28 32 35 42 V VDC IF(AV) IFSM DC Blocking Voltage 30 35 40 45 50 60 V Average Forward Total Device Rectified Current @TA=100 [ ... ]

SBL2040 PDF Datasheet Download