Introduction and usage principle of illuminance meter
An illuminance meter (or lux meter) is an instrument that specializes in measuring luminosity and brightness. It consists of a host and a light sensor. The measurement range is 0-50000. The average indoor illuminance is from 100-1000lux, and the outdoor sunlight illuminance is about 50000lux. Lux is a unit of illuminance, indicating the density of light shining on a surface. Its applications are mainly indoors, offices, laboratories, and environmental research.
Lux Meter - Measuring Principle of Lux Meter
Photovoltaic cells are photoelectric components that directly convert light energy into electrical energy. When the light hits the surface of the selenium photovoltaic cell, the incident light passes through the metal thin film 4 and reaches the interface between the semiconductor selenium layer 2 and the metal thin film 4, generating a photoelectric effect on the interface. The magnitude of the generated photocurrent has a certain proportional relationship with the illuminance on the light-receiving surface of the photocell. At this time, if an external circuit is connected, a current will flow, and the current value will be indicated on the microammeter with lux (Lx) as the scale. The magnitude of the photocurrent depends on the intensity of the incident light. The illuminance meter has a shifting device, so it can measure high illuminance or low illuminance. Types of illuminance meters: 1. Visual illuminance meter: inconvenient to use, low accuracy, rarely used 2. Photoelectric illuminance meter: commonly used selenium photocell illuminance meter and silicon photocell illuminance meter
Light Meter - Types of light meter cited:
1. Visual illuminance meter: inconvenient to use, low accuracy, rarely used
2. Photoelectric illuminance meter: commonly used selenium photocell illuminance meter and silicon photocell illuminance meter
The composition and use requirements of the photoelectric illuminance meter:
1. Composition: Microammeter, shift knob, zero point adjustment, terminal, photocell, V(λ) correction filter, etc.
Commonly used selenium (Se) photocell or silicon (Si) photocell illuminance meter, also known as lux meter
2. Requirements for use:
① Photovoltaic cells use selenium (Se) photocells or silicon (Si) photocells with good linearity; they can maintain good stability after long-term work and have high sensitivity; when E is high, choose high internal resistance photocells, which have low sensitivity and good linearity , not easily 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
③Add a cosine angle compensator (opalescent glass or white plastic) in front of the photocell because when the incident angle is large, the photocell deviates from the cosine rule
④ The illuminance meter should work at room temperature or close to room temperature (photocell drift changes with temperature)
