This part is a kind of semiconductor called 1A3.
Function of this product has 1 Amp Miniature Plastic Silicon Rectifier 50 to 1000 Volts.
Manufacturers : Micro Commercial Components
Image and pinout :
Some of the text within the PDF file :
MCC Features l l l High Reliability Low Leakage Low Forward Voltage Drop omponents 21201 Itasca Street Chatsworth !"# $ % !"# 1A1 THRU 1A7 1 Amp Miniature Plastic Silicon Rectifier 50 to 1000 Volts l Exceeds Environmental Standards of MIL-S-19500/228 l Case: Molded plastic black body, R-1 l Epoxy: UL 94V-O rate flame retardant l Lead: MIL-STD-202E method 208C guaranteed l Polarity: Indicated by Cathode Band R-1 o Maximum Ratings l l l Operating Temperature: -55 C to +150 C Storage Temperature: -55 C to +150 C Maximum Thermal Resistance: 60 C/W Junction to Ambient o D o o o MCC Catalog Number 1A1 1A2 1A3 1A4 1A5 1A6 1A7 Device Marking -- Maximum Recurrent Peak Reverse Voltage 50V 100V 200V 400V 600 [ ... ]