How to use the light meter

Illuminance meter (or lux meter) is a special instrument for measuring luminosity and brightness. That is to measure the light intensity (illuminance) 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. Illuminance meters are usually composed of selenium photovoltaic cells or silicon photovoltaic cells and microammeters.
How to use the light meter:
1. Turn on the power first.
2. Open the detector cover and place the photodetector horizontally in the measuring position.
3. Find a suitable measurement gear.
4. The illuminance meter starts to work and displays the illuminance value on the display.
5. The data displayed on the display screen changes constantly. When the displayed data is relatively stable, press the HOLD key (⑧ key) to lock the data.
6. Read and record the observations displayed in the reader. The observed value is equal to the product of the number displayed in the readout and the span value.
7. Press the lock switch again to cancel the reading lock function.
8. For each observation, take three consecutive readings and record.
9. After the measurement work is completed, press the power switch key to cut off the power supply.
10. When we finish using the illuminometer, we need to cover the photodetector and put it back in the box.
  Precautions:
1 Photocells are applied with selenium (Se) photocells or silicon (Si) photocells with good linearity; they can maintain good stability after long-term operation, and have high sensitivity; when E is high, choose photocells with high internal resistance, which have low sensitivity and good linearity , Not easily damaged by strong light exposure.
2. There is a V (λ) correction filter inside, which is suitable for the illumination of different color temperature light sources, and the error is small.
3. A cosine angle compensator (opal white glass or white plastic) is added in front of the photocell because the photocell deviates from the cosine rule when the incident angle is large.
4. The illuminometer should work at or near room temperature (photocell drift changes with temperature.