VEMT2000 and VEMT2020 Series Phototransistors. The VEMT2000 and VEMT2020 series, from Vishay Semiconductor, is a family of silicon NPN epitaxial planar phototransistors. They are in surface mount (SMD) subminiature packages with a choice of lead options. The VEMT2000 and VEMT2020 have a black plastic package which provides a daylight filter, blocking out ambient visible light. Suitable applications for the VEMT2000 and VEMT2020 phototransistors include; photo interrupters, miniature switches, detectors in automotive applications, counters, encoders and position sensors.. Features of the VEMT2000 and VEMT2020 phototransistors: Subminiature package Surface mounted (SMD) Different lead types: GW and RGW High radiant sensitivity Fast response times Angle of half intensity: 15°