How to Use a Lux Meter?

The lux meter is the instrument for measuring the amount of light coming from a luminous object. The device gives the measurement directly in lux, hence its name of lux meter.

Do you know the units of measurement for the following parameters?

• The length? The meter (m).
• The mass? The kilogram (kg).
• The weather? The second (s).
• The electric current? The ampere (A).
• Temperature? The Kelvin (K).
• The amount of material? The mole (mol).
• The luminous intensity? The candela (cd).

These are the seven basic units of the international measurement system. If no one calculated in the same way, I do not tell you the consequences! Some are familiar, others less like mole and candela. The latter is unknown to the general public while it can provide valuable information. Before, let’s take a look at the four primary factors of light.

• Luminous flux: indicates the total amount of light emitted in all directions by a primary source (light-emitting such as the sun, the flame of the candle, the electric bulb …). The unit of measurement is the lumen.
• The luminous intensity: is measured in candela as we saw above. This is the luminous flux emitted in a given direction.
• Illumination: corresponds to the luminous flux received per unit area. It can be quantified in lux.
• Luminance: characterizes the luminous aspect of an illuminated surface, which becomes a secondary source (non-emitting light like the mirror, the surface of the water …). It is expressed in candela /m2.

The unit of measure that interests me here is lux. Practical to quantify the illumination! Attention, buying a 100-watt incandescent bulb, you do not take into account the power of lighting (1.380 lumens) but the power consumption that is expressed in watt. It is not for nothing that low consumption light bulbs offer equivalent brightness (1350 lumens) for lower power (18 watts instead of 100).

An essential, longer life and less salty bill. In short, the lux allows knowing the conditions of lighting. I see that there are basically who fall asleep. To be more explicit, here is a table of the different values according to a specific situation.

• 0.5 Lux: full moon night.
• 10 Lux: twilight, or candle lighting.
• 20 to 80 Lux: illuminated city.
• 100 Lux: minimum brightness for reading a text.
• 100 to 200 Lux: domestic lighting.
• 300 to 500 Lux: public places.
• 1,000 Lux: local well lit.
• 5,000 Lux: Lux outside in overcast weather.
• 10,000 Lux: outside in average time.
• 20,000 Lux: intense artificial lighting (close to a 50W halogen lamp).
• 50,000 to 100,000 Lux: outdoors in sunny weather.

Capito? And after, what can it do will answer me jaded? Imagine that you enter a public place like a train station, a building … The last thing is not to be blinded by lamps or plunged into darkness. Rather than make facilities at random, it is good to have a standard reference to all. Another example: when you buy a TV or computer screen, what is its contrast ratio, brightness? If you are looking good, lux is mentioned! As many small details that you seek the eye if you pay attention.

Instructions

ATTENTION: The measurement with a lux meter will give you a value of illumination in lux. If you want a luminous flux value in the lumen, see the document  Illuminance & Luminous Flux.

1. Initially, the sensor is closed.

2. You have to open it. Remove the cover in front of the sensor.

3. Turn on the lux meter by selecting the first caliber: 200.

4. Place the support tube to channel the light towards the lux meter and place it on top.

5. If, and only if you read the value one on display, it is because the illumination emitted is too loud compared to the caliber you have chosen. This caliber is, therefore, too small.

6. Choose a template that allows you to read a value, in lux, of the light intensity.