This part is a kind of semiconductor called BY179.

Function of this product has Silicon-Bridge Rectifiers.

Manufacturers : Diotec Semiconductor

Image and pinout :

Some of the text within the PDF file :

Diotec Silicon-Bridge Rectifiers BY 164, BY 179 Silizium-Brückengleichrichter Nominal current – Nennstrom Alternating input voltage Eingangswechselspannung Plastic case Kunststoffgehäuse Weight approx. Gewicht ca. BY 164 BY 179 1.5 A 80 V 250 V 19 x 5 x 10 [mm] 1.8 g Dimensions / Maße in mm Standard packaging: bulk Standard Lieferform: lose im Karton Maximum ratings Type Alternating input voltage Typ Eingangswechselspanng. VVRMS [V] BY 164 80 BY 179 250 Rep. peak reverse volt. ) Period. Spitzensperrspg.1) VRRM [V] 160 500 1 Grenzwerte Surge peak reverse volt.1) Stoßspitzensperrspanng.1) VRSM [V] 200 800 Repetitive peak forward current Periodischer Spitzenstrom Rating for fusing, t < 10 ms Grenzlastintegral, t < 10 ms Peak fwd. surge current, 50 Hz half sine-wave, superimpo [ ... ]

BY179 PDF Datasheet Download