This part is a kind of semiconductor called ZPD15.

Function of this product has ZENER DIODES.

Manufacturers : General Semiconductor

Image and pinout :

Some of the text within the PDF file :

ZPD1 THRU ZPD75 ZENER DIODES DO-35 FEATURES ♦ Silicon Planar Zener Diodes ♦ The Zener voltages are graded according to the international E 12 standard. Smaller voltage tolerances and other Zener voltages are available upon request. max. ∅.079 (2.0) max. .150 (3.8) min. 1.083 (27.5) Cathode Mark min. 1.083 (27.5) ♦ These diodes are also available in the Mini-MELF case with the type designation ZMM1 … ZMM75. max. ∅.020 (0.52) MECHANICAL DATA Case: DO-35 Glass Case Weight: approx. 0.13 g Dimensions are in inches and (millimeters) MAXIMUM RATINGS Ratings at 25°C ambient temperature unless otherwise specified. SYMBOL VALUE UNIT Zener Current (see Table “Characteristics”) Power Dissipation at Tamb = 25°C Junction Temperature Storage Temperature Range Ptot Tj TS 500 [ ... ]

ZPD15 PDF Datasheet Download