What are the requirements for using an illuminometer?
1. Photocells should use selenium (Se) photocells or silicon (Si) photocells with good linearity; Maintains good stability and high sensitivity even after prolonged work; When using high E, choose photocells with high internal resistance, which have low sensitivity and good linearity, and are not easily damaged by strong light irradiation;
2. Internal payment with V（ λ） Correct the filter, suitable for using the illumination of a heterochromatic temperature light source, with small errors;
3. The reason for adding a cosine angle compensator (milky white glass or white plastic) in front of the photocell is that when the incident angle is large, the photocell deviates from the cosine rule;
4. The illuminometer should operate at or near room temperature (the drift of the photocell changes with temperature).
Classification of illuminometers:
1. Visual illuminometer: inconvenient to use, low accuracy, rarely used;
2. Photoelectric illuminometer: commonly used selenium photocell illuminometer and silicon photocell illuminometer.
Illuminometer (also known as Lexometer) is an automatic printed fiber optic optical testing instrument that measures the intensity of artificial and natural light. It solves the problem of continuous measurement of light intensity and automatic recording. It is composed of a photodetector, an automatic shift amplification circuit, a curve recording device, a digital printing device, and an instantaneous digital display device. The curve recording device adopts a fiber optic frictionless recording method, and the photodetector is composed of a filter and a blue silicon photocell, so that the visible spectrum response curve conforms to the human visual spectrum curve specified by the International Commission on Illumination (CIE).
The testing principle of an illuminometer is a photoelectric element that directly converts light energy into electrical energy. Illuminance is the surface density of the luminous flux received on the illuminated plane. Illuminometer is used to measure the intensity of light (illuminance), which is the degree to which an object is illuminated, that is, the ratio of the luminous flux obtained on the surface of the object to the illuminated area. It is one of the most commonly used instruments in illuminance measurement.
The structural principle of an illuminometer: The illuminometer consists of a photometer head (also known as a light receiving probe, including a receiver, V（ λ） It consists of two parts: a filter, a cosine corrector, and a reading display. Commonly used selenium (Se) photocells or silicon (Si) photocells, also known as lux meters.
