Types and Usage Methods of Illuminance Mete
Illuminance meters are distinguished by photoelectric conversion devices, mainly including silicon (selenium) photovoltaic cell illuminance meters and photoelectric tube illuminance meters. The illuminance value can be displayed by numbers or indicated by pointers. Regardless of the type of illuminance meter, it is composed of a photometric probe, a measuring or conversion circuit, and an indicating instrument.
The basic characteristics of illuminance meter and quantitative expression of error
The ratio of the output value of the photocurrent or voltage generated by a spectral responsivity detector under monochromatic radiation with a wavelength of to the monochromatic radiation flux is called the spectral responsivity of the detector. Represented by S. The expression is: the ratio of the spectral responsivity of the wavelength to the spectral responsivity of the reference wavelength, which is called the relative spectral responsivity. Represented by S: the variation of responsivity with wavelength ..
Instructions for using an illuminance meter
① Turn on the power.
② Open the cover of the photodetector and place the photodetector horizontally in the measurement position.
③ Select the appropriate measurement gear.
If only "1" is displayed on the left end of the screen, it indicates excessive illumination and requires pressing the range key (⑧ key) to adjust the measurement factor.
④ The illuminance meter starts working and displays the illuminance value on the display screen.
⑤ The data displayed on the screen is constantly changing. When the displayed data is relatively stable, press the HOLD key (⑧ key) to lock the data.
⑥ Read and record the observed values displayed in the reader. The observed value is equal to the product of the displayed number and the range value in the reader. For example, if 500 is displayed on the screen and the status is "× 2000" in the lower right corner, the measured illuminance value is 1000000lx, which is (500 × 2000).
⑦ Press the lock switch again to cancel the read value lock function.
⑧ During each observation, take three consecutive readings and record them.
⑨ After each measurement is completed, press the power button to cut off the power.
⑩ Cover the photodetector lid and put it back in the box
