The basic knowledge about the illuminance meter is summarized
Human beings and all creatures live in the world of light, without light, life activities will stop. In the practice of human beings reusing natural light sources and inventing artificial light sources, relative comparisons of luminosity are carried out all the time. Photometry has a wide range of applications in daily life. Therefore, manufacturers have developed various photometers, and the illuminance meter is one of them. A sort of.
The lux meter (or lux meter) is an automatic printing optical fiber and an optical test instrument for measuring the intensity of artificial light and natural light. It solves the problem of continuous measurement of light intensity and automatic recording. It is composed of a photodetector, an automatic gear shifting amplifier circuit, a curve recording device, a digital printing device and an instantaneous digital display device. The composition of photovoltaic cells makes the visible spectrum response curve conform to the human visual spectrum curve stipulated by the International Commission on Illumination (CIE).
The test principle of the illuminance meter: a photoelectric element that directly converts light energy into electrical energy. Illuminance is the areal density of the luminous flux received on the illuminated plane. The illuminance meter is used to measure the light intensity (illuminance), which is the degree to which the object is illuminated, that is, the ratio of the luminous flux obtained on the surface of the object to the illuminated area, and is one of the most widely used instruments in illuminance measurement.
The structural principle of the illuminance meter: The illuminance meter is composed of two parts: a photometric head (also known as a light receiving probe, including a receiver, a V (λ) pair filter, and a cosine corrector) and a reading display. Commonly used selenium (Se) photocell or silicon (Si) photocell illuminance meter, also known as lux meter.
Requirements for the use of the illuminance meter: The probe of the illuminance meter is made of glass, which is easy to break and damage, and the waterproof effect is poor when used.
1. Photocells should use selenium (Se) photocells or silicon (Si) photocells with good linearity; they can still maintain good stability and high sensitivity after working for a long time; when E is high, choose photocells with high internal resistance, and their sensitivity is low and linear Well, it is not easy to be damaged by strong light;
2. There is a V (λ) correction filter inside, which is suitable for the illumination of light sources with different color temperatures, and the error is small;
3. Add a cosine angle compensator (opalescent glass or white plastic) in front of the photocell because the photocell deviates from the cosine rule when the incident angle is large;
4. The illuminance meter should work at or near room temperature (photocell drift changes with temperature).
Classification of illuminometers:
1. Visual illuminance meter: it is inconvenient to use, the accuracy is not high, and it is rarely used;
2. Photoelectric illuminance meter: Selenium photocell illuminance meter and silicon photocell illuminance meter are commonly used.
