ABSTRACT
Reflective switches may be divided into separate categories: surface detectors and mark or line detectors. A highly polished surface will yield a high specular reflectance of energy, whereas a surface with diffused reflectance will have a high diffused reflectance component of energy. The housings of most of analog sensors hold additional electrical components necessary to add optical and electrical flexibility to the sensor. The effective photo-sensitive area detects the energy reflected back from the reflecting surface. The reflective sensor will normally work better than the transmissive sensor in three types of applications. The first of these is obviously when there is access to only one side of the object to be detected. The second of these is in liquid level detection. The third application involves precise height measurement, where the width across the material is very large compared to the distance from the detector to the material.
