What does a lumen measure? Basic light units and quantities. Luminous flux unit

How to choose the right LED lamp.

What is written on the boxes, what do certain parameters mean.

LED (“Light” Emitting Diode") means LED.

In order to decide on the choice of lamp.

Most important indicator lamps are

Light flow is the amount of visible light.

Designated Lm (lumen). In order to understand a lot or a little.

It is enough to know that the usual a 60 watt incandescent lamp is approximately 660 lm.

A 100 watt lamp is 1140 lm.

Indicated in watts (W) - this is how much electricity is consumed (“how much the meter turns up”). A more powerful lamp does not mean brighter.

An energy-saving lamp is determined precisely by the ratio of these 2 parameters - getting as much light Lm as possible and spending as little electricity W as possible on it. Our LED lamps are approximately 85-115 lm/W.

Voltage.

Designated V (volt), as a rule, lamps operate on 220 volts, or 12V (via a step-down transformer or automobile), even less often they operate on 24-36v (ships and industrial premises with high humidity). On the box they write the limits from and to (how sensitive the lamp is to voltage changes). LED lamps operate in the range from 100 to 240v.

Temperature of light.

Designated K (Kelvin) how “warm” or “cold” the light from the lamp is.

It has nothing to do with the physical heating of the lamp! Varies depending on the number of watts only for lamps with incandescent filament.

A little crafty indicator that has it precise measurement. Different lamps with the same indicator may differ in shades of light.

In energy saving and LED lamps this indicator is achieved by adding one or another phosphor during production

Many people, when buying a lamp, do not pay attention to this indicator, and after installing the lamp they are dissatisfied with the fact that “The light is somehow ghostly or cold” or, conversely, that it is too “yellow”.

To prevent this from happening and to ensure that your expectations are not mistaken, we present the table below

The lower the indicator, the warmer the light, the higher the colder.

From household examples, an incandescent lamp 60 watts has an indicator of 2700K

Daylight in cloudy weather - 6500-7000 K.

Lamps generally have indicators

2700K(warm white)

4100K(neutral white)

6500K(cold)

7500 (white daylight).

Warm light - more homely and cozy, for comfort and relaxation. Lamps with warm light are installed in bedrooms and living rooms.

Neutral and cold light is more effective and puts you in a working mood; it more clearly shows objects as they are. Lamps with neutral and cold light are installed to illuminate work areas, offices, dressing rooms, and hobby rooms.

Neutral and cool blue radiation in itself can affect a person’s biological clock, so for indoor lighting you should choose high-quality lamps with a color temperature of 4000K-6500K, which corresponds to natural daylight.

Types of lamp bases

The most common screw base E27 called an ordinary screw, diameter 27 mm (the letter E means Edison - one of the inventors).

Sometimes E40 (for high-power industrial lamps)

Very common screw E14 base popularly called “minion” or small screw, diameter 14mm. Sometimes there are “foreign” less common standards such as E10 or E12.

(distance between contacts) It happens with both 220v and 12v lamps, usually mainly with either halogen soffit lamps or LED ones. Lamps are used in recessed recessed luminaires

Typically, halogen mirror or LED bulbs only have 220 volts.

The lamp is inserted and turned clockwise

Used in GX type luminaires. It is popularly called a tablet because the lamp is flat and large. Very often used in lamps for suspended ceilings to save space between ceilings

Color rendering index.

Denoted Ra (aka CRI).

This is an indicator of how accurately the shades of illuminated objects are conveyed.

Ra 0 - everything is in black and white.

This indicator determines how correctly colors will be perceived in a given light. For example, light sources with Ra>95 are required for museums and art galleries; light sources with Ra>90 are suitable for clothing stores and boutiques. For home, it is recommended to choose lamps and luminaires with a color rendering index value of at least Ra80

Lower values are allowed for lighting, utility and utility rooms, roads, courtyards in areas where the quality of light is not important, but energy saving is the main thing.

Our LED lamps have 80 - 92 Ra

Corner luminous flux .

It happens 20, 35. The most common for spotlights- 120 degrees.

With the same luminous flux, completely different lighting effects.

For accent light (if you need to illuminate something specifically), it is better to choose a lamp with a small angle.

For general lighting (ceiling), it is better to choose a lamp with a wide angle, such as 120 degrees.

About point ones ceiling lamps there is a detailed

Heatsink in LED lamps:

Any LED lamp must have a heat sink.

In our understanding, LED lamps do not heat up, however For LEDs, their own heat is destructive. This is what the radiator is made for.

The better and larger the radiator, the longer the LED lamp will last.

Unfortunately on this moment It is impossible to produce an LED lamp that is powerful, small and durable at the same time. (One of the parameters will decrease at the expense of the others). The more powerful the LED lamp, the larger it is(if we are talking about high-quality LED lamps)

Some low-quality manufacturers, in order to reduce the cost of their products at any cost, reduce the radiator, according to the principle “it will last a year, but oh well.”

Most buyers choose LED lamps based on two criteria: power/price, which is fundamentally wrong, since more power- doesn't mean more light.

High-quality radiator - aluminum with the addition of silver and copper, is a guarantee for long term service without reducing the luminous flux over time.

Ripple in LED lamps. not visible to the naked eye

In high-quality LED lamps, pulsation is absent or minimal.

Manufacturers quality lamps indicate for example:

No pulsation
0% ripple factor.

This is a very important indicator. Since pulsation negatively affects vision and fatigue, especially when working with moving objects or when reading. It can cause headaches, pain in the eyes, and so on, depending on the degree of pulsation and the time spent in such lighting.

This effect is difficult to notice with the naked eye. The lamp flickers so often that the eye (pulsation) does not see it, but it puts a strain on the brain and vision.

The easiest way to determine whether an LED lamp has pulsation is to point your smartphone camera at it.

You will get something like this picture with moving stripes.

This is typical for cheap and not very high-quality lamps, whose manufacturers do not indicate this indicator on the packaging and are silent. This is due to the incorrect design of the driver, which produces not a constant, but a pulsating current.

Such lamps are not suitable for basic home and work lighting.

But they can be used for additional, non-primary lighting: lighting of storage rooms, attics, basements, some street lamps, duty lamps.

Or for local lighting: lighting for pictures, in the refrigerator, etc.

But you definitely don’t need to install such lamps in chandeliers, sconces (especially for reading), or work lamps.

It is strictly forbidden to use lamps with a high degree of pulsation when working with moving mechanisms and machines. The rotation speed may coincide with the flickering frequency and the mechanism will appear to be motionless, which may result in serious injury.

ONLY transparent lamps (incandescent or LED) are used in crystal lamps, so that the crystal “plays” and breaks the light needed point source light (sun, candle, tungsten filament, open LED).

This is essentially ordinary lamp incandescent, come in different shapes.

Due to the increased length of the tungsten filament, it looks more impressive. They are often placed in loft-style lamps.

The bulb has a yellowish tint, so the light is warmer than that of an ordinary incandescent lamp 2100-2400K. This lamp will last about 2 years.

These lamps are suitable for additional lighting, creating a more comfortable atmosphere. It is not advisable to use it for main and task lighting.

Buy LED lamps cheap?

Cheap LED lamps exist on the market, but, as a rule, these are low-efficiency lamps whose power consumption is higher and whose luminous flux is low, or their design allows the manufacturer not to spend significant funds on the driver and cooling radiator.

High-quality lamps or complex decorative LED products cannot have a low price. The low price may be due to raw materials of dubious quality. LED lamps famous brands are often counterfeited and can be sold below the average market value, although more often they try to keep prices at an appropriate level to obtain excess profits. LED lamps Low quality can cause serious harm to health and vision. They contain toxic materials that often have a distinct chemical odor when the lamp heats up during operation. The light from LED counterfeits does not correspond to the declared color temperature and power. Diffusers on cheap lamps perform a purely aesthetic function; therefore, they cannot protect the eyes from too bright radiation and can cause a burn to the retina. High-quality LEDs do not have infrared or ultraviolet healing in their spectrum.

Name of quantity	Unit name	Expression via SI units (SI)	Unit designation
Russian	between- folk
The power of light	candela	cd	cd	CD
Light flow	lumen	cd·sr	lm	lm
Light energy	lumen second	cd·sr·s	lm s	lm·s
Illumination	luxury	cd·sr/m 2	OK	lx
Luminosity	lumen per square meter	cd·sr/m 2	lm m 2	lm/m2
Brightness	candela per square meter	cd/m2	cd/m2	cd/m2
Light exposure	lux-second	cd·sr·s/m 2	lx s	lx·s
Radiation energy	joule	kg m 2 /s 2	J	J
Radiation flux, radiation power	watt	kg m 2 /s 3	W	W
Light equivalent of radiation flux	lumen per watt		lm/W	lm/W
Surface radiation flux density	watt per square meter	kg/s 3	W/m2	W/m 2
Energy luminous intensity (radiant intensity)	watt per steradian	kg m2/(s 3 sr)	Tue/Wed	W/sr
Energy brightness	watt per steradian square meter	kg/(s 3 sr)	W/(sr m 2)	W/(sr m 2)
Energy illumination (irradiance)	watt per square meter	kg/s 3	W/m2	W/m 2
Energetic luminosity (emissivity)	watt per square meter	kg/s 3	W/m2	W/m 2

What is "luminous flux" called?

First of all, it is worth understanding what this term is called in physics.

Luminous flux is the power of light emission, assessed by the light sensation it produces from the point of view of the human eye. This is a quantitative characteristic of the radiation of a light source.

The numerically considered quantity is equal to the energy of the light flux passing through a certain surface per unit time.

Luminous flux unit

How is the physical quantity in question measured?

According to the current SI (International System of Units) standards, a specialized unit called a lumen is used for this.

This word was derived from the Latin noun meaning "light" - lūmen. By the way, this word also gave rise to the name of the secret organization “Illuminati,” which became a subject of general interest several years ago.

In 1960, the lumen officially began to be used throughout the world as a unit of measurement of luminous flux, and remains so to this day.

In abbreviated form in Russian, this unit is written as “lm”, and in English - lm.

It is worth noting that in many countries the light power of light bulbs is not measured in watts (as in the vast former USSR), namely in lumens. In other words, overseas consumers consider not the amount of energy consumed, but the strength of the light emitted.

By the way, because of this, on the packaging of most modern energy saving light bulbs there is information about their characteristics in both watts and lumens.

Formula

The unit of measurement of luminous flux under consideration is numerically equal to light from a point isotropic source (with a force of a candela) emitted into a solid angle equal to one steradian.

In the form of a formula, it looks like this: 1 lm = 1 cd x 1 avg.

If we take into account that a complete sphere forms a solid angle of 4P sr, it turns out that the total luminous flux of the above source with a power of one candela is equal to 4P lm.

What is "candela"

Having learned what a lumen is, you should pay attention to the unit associated with it. We are talking about CD - that is, candela.

This name was derived from Latin word"candle" (candela). From 1979 to this day it is according to the SI (International System of Units).

In fact, one candela is the intensity of light emitted by one candle (hence the name). It is worth noting that in Russian for a long time Instead of the term "candela" the word "candle" was used. However, this name is outdated.

From previous paragraph it is clear that lumen and candela are related (1 lm = 1 cd x 1 sr).

Lumens and Luxes

Considering the features of such a light value as a lumen, it is worth paying attention to such a close concept as “lux” (lx).

Like candelas and lumens, lux is also a lighting unit. Lux is a unit of illumination used in the SI system.

The relationship between lux and lumen is as follows: 1 lux is equal to 1 lm of luminous flux, evenly distributed over a surface of 1 square meter. Thus, in addition to the above lumen formula (1 lm = 1 cd x 1 sr), this unit has one more: 1 lm = 1 lx/m2.

Speaking more in simple language, a lumen is a measure of the amount of light emitted by a particular source, such as the same light bulb. But lux shows how light the room really is, since not all light rays reach the illuminated surface. In other words, lumen is the light that came out of the source, lux is the amount of it that actually reached the illuminated surface.

As already mentioned, not all the emitted light always reaches the illuminated surface, because often in the path of such rays there are obstacles that create shadows. And the more there are on the way, the less illumination there is.

For example, when the library hall was built, many light bulbs were hung in it. The total illumination of this empty room was 250 lux. But when renovation work were completed and furniture was brought into the hall, the light level dropped to 200 lux. This is despite the fact that the light bulbs, as before, produced the same amount of lumens of light energy. However, in the path of each of its rays, obstacles now appeared in the form of shelves with books and other library furniture, as well as visitors and employees. Thus, they absorbed part of the emitted light, reducing the total amount of illumination to the hall.

The situation given as an example is not an exception of its kind. Therefore, when constructing any new buildings or decorating the interior of existing ones, it is always important to take into account its illumination. Most institutions even have a system of lighting standards; naturally, it is measured in lux.

IN modern world There are several programs in which you can not only simulate the design of your room yourself, but also calculate how light it will be. After all, the vision of its inhabitants depends on this.

Lumen and Watt

In the past, in our country, when choosing a light bulb, we were guided by the number of watts it consumes. The more of them, the better the light of this device.
Today, even in our country, radiation power is increasingly measured in lumens. In this regard, some believe that lm and W are quantities of the same kind, which means that lumens to watts and vice versa can be freely converted, like some other SI units.

This opinion is not entirely correct. The fact is that both units of measurement under consideration are used for different sizes. So, a watt is not a light unit, but an energy unit that shows the power of a lighting source. While lumen shows how much light a particular device emits.

For example, a regular incandescent lamp that consumes 100 watts produces 1340 lumens of light. At the same time, its more advanced (today) LED “sister” produces 1000 lm while consuming only 13 W. Thus, it turns out that the light intensity of a light bulb is not always directly dependent on the amount and power of energy absorbed by it. The substance used for lighting in the device also plays an important role in this matter. This means that there is no direct relationship between lumens and watts.

Moreover, these quantities are really related to each other. The luminous efficiency of any light source (the relationship between the energy consumed and the amount of light produced) is measured in lumens per watt (lm/W). It is this unit that is evidence of the effectiveness of a particular lighting device, as well as its efficiency.

It is worth noting that when great need It is still possible to convert lumens to watts and vice versa. But for this you need to take into account several additional nuances.

The nature of the light source. Which lamp is used in the calculations: incandescent, LED, mercury, halogen, fluorescent, etc.
Light output of the device (how much watt it consumes and how many lumens it produces).

However, in order not to complicate your life, to carry out such calculations you can simply use an online calculator or download it for yourself similar program to a computer or other device.

Multiples of Lumen Units

Lumen, like all its “relatives” in the SI system, has a number of standard multiples and submultiples. Some are used for ease of calculation when one has to deal with either too small or too large values.

If we're talking about about the latter, then they are written in the form of a positive degree, if about the former - in the form of a negative one. Thus, the largest multiple unit of lumen - iottalumen - is equal to 10 24 lm. It is most often used to characterize cosmic bodies. For example, the luminous flux of the Sun is 36300 Ilm.

The most commonly used units are four multiples: kilolumen (10 3), megalumen (10 6), gigalumen (10 9) and teralumen (10 12).

Lumen subunits

The smallest submultiple unit lumen is ioctolumen - ilm (10 -24), however, like iottalumen, it is practically not used in real calculations.

The most commonly used units are millilumen (10 -3), microlumen (10 -6) and nanolumen (10 -9).

Illuminance is the most common photometric quantity, in Everyday life is defined in simple terms: light, dark, twilight, etc. The level of illumination has a significant impact on a person’s well-being and ability to work, his ability to receive information from the most different sources using vision. To create comfortable conditions, it is necessary to measure the illumination and determine the optimal values.

Illumination concept

Determining illumination is impossible without using other parameters of visible light - light units:

Candela (cd). Luminous intensity refers to the basic units international system SI. The previously used name was a candle, which served as a standard for measurements. Now one candela is the luminous efficiency of a monochrome emitter at strictly certain frequency, with a given energy. In domestic use, one candela corresponds to the luminous intensity of one ordinary candle, 100 cd corresponds to a 100 W incandescent lamp;
Luminous flux – lumen (lm), a derived unit of measurement. The definition is closely related to the intensity of light. 1 lumen is the luminous flux of an emitter with an intensity of one candela, distributed over one steradian (solid angle): 1 lm = 1 cd ∙ 1 sr. The typical value for 100 W incandescent lamps with a transparent bulb is 1300-1400 lm.

Illumination depends on these characteristics of the light source and indicates the amount of luminous flux incident on a certain area, measured in lux (lx). A lux is taken as a unit of illumination - this is a luminous flux of one lumen falling perpendicularly onto 1 m2 of illuminated area and evenly distributed over it. It is also defined as the illumination of a sphere with a radius of 1 meter, located inside an emitter with a luminous intensity of 1 cd. It is directly proportional to the intensity of the source and inversely proportional to the square of the distance to it. The source is taken to be an (isotropic) point emitter uniformly emitting light in all directions.

The specific values of candelas, lumens and lux are calculated using the formulas:

E = F / S, where E – illumination, lux; S – area, m2.

E = I / R2, where R is the distance to the source.

From these ratios it is clear how to convert lux to lumens, calculate the required flux at a certain illumination:

F = E × S, where F is the desired luminous flux in lumens, E is the known illumination, lux, S is the area, m2.

The value decreases if the light falls at an angle, then the result must be multiplied by the cosine value of the angle of incidence of the rays:

E = (F / S) × cos i;

E = (I / R2) × cos i.

In the traditional English and American measurement systems, the concept of foot-candela is used. Defined as the illuminance at a distance of one foot produced by a source of luminous intensity of one candela. More than one lux is approximately ten times; it is convenient to use online calculators for conversion.

Average values for some common natural and artificial light sources:

Sun, in mid-latitudes, noon - up to 400,000 lux;
Cloudy weather – 3000 lux;
Sunrise – 1000 lux;
Full moon without clouds – up to 1 lux;
Stadium at artificial lighting– up to 1300 lux.

The indicated values are approximate and cannot be used for calculations - the difference in measurements can be very large.

Primary requirements

The illumination of any object on which the light flux falls does not depend in any way on its properties - they determine only the reflective ability of the surface, which is usually called luminosity or brightness. Reflected light from the ceiling, mirrors and other structures is often used to enhance the effectiveness of the main lighting, so most designs of pendant lamps provide for the direction of part of the light into the upper hemisphere.

Living room – 200 lux;
Bathroom, shower – 80 lux;
Office – 300 lux;
Utility rooms – 50 lux.

For production and service facilities, standardized values are established, specified in the SNiP set of rules.

Lighting calculations are made using cumbersome formulas, which include many parameters: lux and lumens, area, different odds, how many lamps, etc. For simple applications, there are many calculators on the Internet that make calculations much easier.

Measurement

Direct measurement of illumination is carried out special device– a lux meter that displays the result directly in lux. It works on the principle of photoelectric effect, characteristic of some materials: selenium element or semiconductors. In photography, exposure meters are used, giving results in exposure numbers EV.

The lux meter registers the luminous flux in a specific place, taking into account all types of lighting: artificial, natural, reflected.

Symbols on light sources

The ability of a lighting product to create a certain level of illumination is indicated in the form of a luminous flux value in lumens.

Characteristics of the main indicators as applied to lighting: lux, lumens, kelvins, watts. Read!

Considering the current economic situation in our country, now is the time to switch to LED lighting. Why? LED lamps consume much less electricity compared to other light sources, and their technical characteristics are significantly superior to, for example, incandescent lamps.

However, before you go to the store LED equipment, you need to know some of the characteristics of such devices, taking into account which you can choose exactly the lighting device whose characteristics will fully correspond to the operating conditions. In this article we will talk about what watts, lumens, lux and kelvins mean on LED labeling, and also talk about the advantages of LED devices over other light sources.

Watts, lux, lumens, kelvins, as the main characteristics of LEDs

When purchasing incandescent lamps, the consumer is guided by the number of watts indicated on the label, thereby determining how bright the product will shine. In LEDs, this indicator has a completely different meaning.

The number of watts that the manufacturer indicates on the packaging does not characterize the brightness of the device, but the amount of electricity consumed per hour of operation. Naturally, a parallel can be drawn between incandescent lamps and LEDs, focusing only on power. There are even special tables for this. So, for example, an 8-12 watt LED device will shine as brightly as an incandescent lamp with a 60-watt rating. However, the basic unit that determines the brightness of LED lamps is the lumen.

What are lumens in LED lamps

By lumen we mean the amount of luminous flux that is emitted by a light source with a force equal to one candela per angle of one steradian.

For example! An incandescent lamp with a power of 100 W is able to create a luminous flux equal to 1300 lumens, while a much lower power LED can produce a similar indicator

However, in addition to lumens, LED equipment is also characterized by the amount of illumination, which is measured in lux.

What is lux in lighting

Lux is a unit of illumination measurement that is equal to the illumination of a surface area of one square meter with a luminous flux equal to one lumen. So, for example, if you project 100 lumens onto an area of 1 square meter, the illumination indicator will be 100 lux. And if a similar luminous flux is directed at ten square meters, then the illumination will be only 10 lux.

Now, when you are asked: “luxes and lumens, what is the difference?”, you will be able to show off your knowledge and give the interlocutor a comprehensive answer to his question.

What is Kelvin in lighting

As you've probably noticed, incandescent light has a warm yellowish tint, while LEDs have a wide range of colors. Thus, LED equipment is capable of displaying colors from violet to red (in the spectrum of white and yellow flowers). However, the most common colors are still bright white, soft or warm white. Why are we telling you this? The thing is that you can determine the color of the light by the product labeling. To do this, you need to look at such technical characteristics as color temperature, which is measured in Kelvin. The lower the number, the yellower (warmer) the light emitted will be.

For example, a regular incandescent lamp has color temperature, which is in the range between 2700 – 3500 Kelvin. Thus, if you want to purchase an LED lighting fixture that has the same color as an incandescent lamp, choose an LED fixture with a similar color temperature.

Different types of industrial lamps, their advantages and disadvantages

Below is comparison table various types industrial lamps.

Lamp type	Advantages	Flaws
Incandescent lamps	Ease of production Short flare-up period The luminous flux at the end of its service life decreases slightly	Low efficiency Low luminous efficiency Uniform spectral color composition Short service life
Mercury discharge lamp	Low electricity consumption Average efficiency	Intense ozone formation during combustion Low color temperature Low color rendering index Long flare-up
Sodium arc tube lamps	Relatively high luminous efficiency Long service life	Long burn-up time Low environmental performance
Fluorescent lamps	Good light output Variety of light shades Long service life	High chemical hazard index Flickering lamps Need for use additional equipment to start Low power factor
LED bulbs	Low power consumption Long service life High durability resource Diversity color range luminous flux Low operating voltage High level of environmental and fire safety Adjustable intensity	Relatively high price

Based on this table, we can conclude that LED lamps are superior to other types of lighting elements in almost all respects. As for the price, this factor can hardly be called a significant drawback. In addition, when it comes to choosing and installing LED equipment, for example, it will pay for itself in a relatively short time.

Consult about technical characteristics and LED industrial lamps, and also choose from the product you need, you can on our website. Also, our specialists will carry out current lighting at your facility and offer a suitable system for upgrading.