This part is a kind of semiconductor called PS2501-1.

Function of this product has HIGH ISOLATION VOLTAGE SINGLE TRANSISTOR TYPE MULTI PHOTOCOUPLER SERIES.

Manufacturers : California Eastern Labs

Image and pinout :

Some of the text within the PDF file :

PHOTOCOUPLER PS2501-1,-2,-4, PS2501L-1,-2,-4 HIGH ISOLATION VOLTAGE SINGLE TRANSISTOR TYPE MULTI PHOTOCOUPLER SERIES −NEPOC Series− DESCRIPTION The PS2501-1, -2, -4 and PS2501L-1, -2, -4 are optically coupled isolators containing a GaAs light emitting diode and an NPN silicon phototransistor. The PS2501-1, -2, -4 are in a plastic DIP (Dual In-line Package) and the PS2501L-1, -2, -4 are lead bending type (Gull-wing) for surface mount. FEATURES • High isolation voltage (BV = 5 000 Vr.m.s.) • High collector to emitter voltage (VCEO = 80 V) • High-speed switching (tr = 3 µs TYP., tf = 5 µs TYP.) • Ordering number of tape product: PS2501L-1-E3, E4, F3, F4, PS2501L-2-E3, E4 • Safety standards • UL approved: File No. E72422 1 2 PIN CONNECTION (Top View) P [ ... ]

PS2501-1 PDF Datasheet Download