What are lumens in LED lamps and what do they mean. What is a lumen
Instructions
According to the definition, illumination of one lux is created with a luminous flux of one lumen if it uniformly illuminates a surface area of one square meter. Therefore, to convert lumens to lux, use the formula:
Klux = Clumen / Km²
To convert lux to lumens, use the formula:
Klyumen = Klux * Km²,
Where:
Klux – illumination (number of lux);
Clumen – value (number of lumens);
Km² - illuminated area (in square meters).
When making calculations, keep in mind that the lighting should be uniform. In practice, this means that all points on the surface must be equidistant from the light source. In this case, the light must hit all areas of the surface at the same angle. Also note that the entire flux emitted by the light source must reach the surface.
If the light source is close in shape to a point, then uniform illumination can be achieved only on the inner surface of the sphere. However, if the lamp is sufficiently distant from the illuminated surface, and the surface itself is relatively flat and has a small area, then the illumination can be considered almost uniform. A “vivid” example of such a light source can be considered, which, due to its enormous distance, is almost a point source of light.
Example: In the center of a cubic room 10 meters high there is a 100 W incandescent lamp.
Question: what will be the illumination of the ceiling of the room?
Solution: A 100-watt incandescent lamp produces approximately 1,300 lumens (Lm). This flow is distributed over six equal surfaces (walls, floor and ceiling) with a total area of 600 m². Therefore, their illumination (average) will be: 1300 / 600 = 2.167 Lux. Accordingly, the average illumination of the ceiling will also be equal to 2.167 Lux.
To solve the inverse problem (definition luminous flux given illuminance and surface area) simply multiply illuminance by area.
However, in practice, the luminous flux created by a light source is not calculated in this way, but is measured using special instruments - spherical photometers and photometric goniometers. But since most light sources have standard characteristics, for practical calculations use the following table:
Incandescent lamp 60 W (220 V) – 500 Lm.
Incandescent lamp 100 W (220 V) – 1300 Lm.
Fluorescent lamp 26 W (220 V) - 1600 Lm.
Sodium gas discharge lamp (outdoor) - 10000...20000 Lm.
Low pressure sodium lamps - 200 Lm/W.
LEDs – about 100 Lm/W.
Sun – 3.8 * 10^28 Lm.
Lm/W is an indicator of the efficiency of the light source. For example, a 5 W LED will provide a luminous flux of 500 Lm. Which corresponds to an incandescent lamp consuming 60 W of power!
In Soviet times, when choosing a light bulb, consumers were guided by the number of watts in it. The more there are, the brighter the light this device. However, today (when many new varieties of lamps have appeared on store shelves) we are increasingly faced with such a concept as “lumen”. What is it, how does it differ from a watt, and what is the unit called lumen per watt? Let's find answers to these questions.
What is "lumen"
In the middle of the twentieth century. To avoid confusion in units of measurement between different countries, the universal SI system was introduced. It is thanks to her that we have watts, amperes, meters, kilograms, etc.
According to her, (apparent electromagnetic radiation) is In fact, these units measure the amount of light emanating from its source.
Also, to the question of what “lumen” is, you can answer that this is the name of a famous Russian rock band from Ufa. Having started its activity in 1998, it has continued to be loved by many listeners for almost twenty years. Russian Federation and beyond.
Origin of the word
Having learned what a lumen is, it is worth clarifying where this word came from in the Russian language.
Like most SI unit names, the term in question is a Latinism. It is derived from the word “light” (lūmen).
At the same time, some linguists argue that the noun could be formed from the Proto-Indo-European word leuk (white) or from lucmen (the meaning is not precisely established).
What is the difference between lumen and lux
Considering the meaning of the word “lumen”, it is worth mentioning such a close concept as “lux”.
Both of these terms refer to light energy units, but lumen is the entire light emitted by a source, and lux is the amount of light that reached the illuminated surface and was not stopped by some obstacles to form shadows.
The interdependence of these units can be reflected with the following formula: 1 lux = 1 lumen/1 square meter.
For example, if a lamp illuminating an area measuring 1 m 2 emits 50 lumens, then the illumination of this place is equal to 50 lux (50 lm / 1 m 2 = 50 lux).
However, if the same lamp with the same amount of light is used for a room of 10 m2, then the illumination in it will be less than in the previous case. A total of 5 lux (50lm/10m2 = 5 lux).
In addition, such calculations did not take into account the presence of various obstacles that prevent light rays from reaching the surface, which significantly reduces the level of illumination.
Due to this situation, in every country in the world there are lighting standards for various buildings. If it is lower than them, a person’s vision does not receive enough light and deteriorates. For this reason, when planning to make repairs or rearrangements in your home, it is always important to take this nuance into account.
There are also a number of design programs in which such calculations are made automatically.
Lumen and Watt
Having learned the difference and meaning of lumen and lux, it is worth paying attention to another SI unit - the watt.
Because they are used for light bulbs, some believe that these units can be freely related to each other. However, this is not quite true.
The fact is that the power of energy that a light bulb consumes is measured in watts, and the amount of light that it emits is measured in lumens.
In the days when only incandescent lamps existed, it was easier to calculate the amount of light from such a device. Since a 100 W bulb produced about 1600 lumens of light. While a similar 60 W device produces 800 lm. It turned out that the more energy consumed, the better the lighting.
But today everything is different. In recent decades, several new types of lighting sources have been invented (fluorescent, etc.). Their advantage is cost effectiveness. That is, they shine brighter with less energy used.
In this regard, if it is necessary to draw up the relationship between watts and lumens, you need to take into account the type of lamp and look for its aperture in special tables.
It is worth noting that an ordinary person sometimes does not want to rebuild and understand all these subtleties. Therefore the majority domestic producers of the new type of light bulbs, the labels indicate not only the number of lumens, but how much less watts it consumes this device(compared to an incandescent lamp). For example: a 12-watt lamp produces the same light as 75 watts.
Unit of measurement “lumen per watt”: its meaning and scope of application
For example, a classic 40 W incandescent lamp has a light output of 10.4 lm/W. At the same time, for an induction lamp with the same power this figure is much higher - 90 lm/W.
For this reason, when choosing a lighting device for your home, you should not be lazy, but find out the level of its light output. As a rule, such data is on the labels.
There are many myths around the concept of “lumen”, so in order to dispel some of them, let’s consider the most frequently asked questions, such as: how many lumens are in an incandescent lamp, in an LED lamp, how many lumens does 1W of an LED lamp contain, how to determine its luminous flux , and which LED lamps are similar to incandescent lamps.
First, let’s figure out what the concept of “lumen” means. A lumen is a unit of measurement of the luminous flux emitted by a light source, which may be an incandescent lamp, LED lamp, light emitting diode or other lighting fixture.
To make it easier to carry out comparative analysis, you can refer to the table, which shows the ratio of DP (lumens) to the power of the lighting device (W) for incandescent, fluorescent and LED lamps. Based on these data, it is clear that LED lamps are 10 times more efficient than incandescent lamps, and 2 times more efficient than fluorescent lamps. Moreover, unlike fluorescent lamps and incandescent lamps, an LED lamp, and therefore an LED, emits directional light, from which we can conclude that the illumination from an LED lamp will be significantly higher. Therefore, using an LED street lamp as lighting, you can achieve much better illumination than when using other lamps.
As for the number of lumens in a 1W LED lamp.
For LEDs, the luminous flux ranges from 80 to 150 Lm per 1 W. This is due to some differences in the current-voltage characteristics of LEDs and cooling systems. The luminous flux of experimental LEDs reaches 220 Lm/W, but such LEDs are not found in mass production.
How can you determine the number of lumens in a lamp or light bulb?
Usually this information is indicated on the packaging or in the instructions for the product, but you can also use tabular data.
To independently determine lumens, you need a lux meter that determines the level of illumination in each area of the room. Lux in this case is the quantitative ratio of lumens per lighting area (1 lux-1 lumen per m2). When the luminous intensity emanating from an isotropic source is 1 candela, the total luminous flux is 4
Lumen (lm, lm)- unit of measurement of luminous flux in SI. Where SI is the system of units physical quantities, (French: Le Syst?me International d'Unit?s, SI).
One lumen is equal to the luminous flux emitted by a point isotropic source with a luminous intensity equal to one candela into a solid angle of one steradian (1 lm = 1 cd? sr). The total luminous flux created by an isotropic source with a luminous intensity of one candela is equal to 4? lumens.
A typical 100 W incandescent lamp produces a luminous flux of approximately 1300 lm. A 26 W compact fluorescent fluorescent lamp produces a luminous flux of approximately 1600 lm. The luminous flux of the Sun is 3.63·10 to the 28th power of lm.
Lumen is the total luminous flux from a source. However, this measurement usually does not take into account the focusing efficiency of the reflector or lens and is therefore not a direct parameter for assessing the brightness or useful performance of the beam. A wide beam of light can have the same lumens as a narrowly focused beam. Lumens cannot be used to determine beam intensity because the lumen rating includes all scattered wasted light.
Lux (lx)- unit of measurement of illumination in the SI system.
Lux is equal to the illumination of a surface with an area of 1 sq. m when the luminous flux of radiation incident on it is equal to 1 lumen.
100 lumens were collected and projected onto a 1-meter square area. The illumination of the area will be 100 lux. The same 100 lumens aimed at 10 square meters will produce 10 lux of illumination.
Candela (cd, cd)- one of the seven basic units of measurement of the SI system, equal to the intensity of light emitted in a given direction by a source of monochromatic radiation with a frequency of 540·10 to the 12th power of Hz, the energy intensity of which in this direction is (1/683) W/sr. Steradian (Russian designation: ср, international: sr) is a unit of measurement of solid angles.
The selected frequency corresponds to the color green. The human eye is most sensitive in this region of the spectrum. If the radiation has a different frequency, then greater energy intensity is required to achieve the same light intensity.
Previously, candela was defined as the intensity of light emitted by a black body perpendicular to a surface with an area of 1/60 sq. cm at the melting point of platinum (2042.5 K). In the modern definition, the coefficient of 1/683 is chosen so that the new definition matches the old one.
The intensity of light emitted by a candle is approximately equal to one candela (Latin candela - candle), so this unit of measurement was previously called a “candle”, now this name is outdated and is not used.
Luminous intensity of typical sources:
| Source | Power, W | Approximate luminous intensity, cd |
| Candle | 1 | |
| Modern (2016) incandescent lamp | 100 | 100 |
| Regular LED | 0,015 | 5 mkd |
| Super bright LED | 1 | 25 |
| Ultra-bright LED with collimator | 1 | 1500 |
| Modern (2016) fluorescent lamp | 20 | 100 |
Black Diamond is a trendsetter in the world of professional mountaineering and climbing equipment. The brand produces high-quality headlamps and pendant lamps that can be used even at a depth of one meter underwater for half an hour. BD offers travel lighting with luminous flux indicators of up to 200 lumens with relatively low weight. Many flashlights are equipped with several lighting modes for ease of use on the mountaineering route and at home. Bright, light, neat and practical, BlackDiamond flashlights will not let you down even in the most extreme situations.
Luminous flux of lamps (lm)
big LED-high, big LED-med, big LED-low, 5 MM - High, 5 MM - medium, 5 MM - low
| Black Diamond Lantern (BD) | Luminous flux, (lm) |
| Icon | 200 |
| Spot new | 200 |
| Cosmo new | 90 |
| Wiz new | 30 |
| Ion | 80 |
| Ember Power Light | 150 |
| Orbit Lantern | 105 |
| Voyager Lantern | 140 |
| Petzl flashlight | Luminous flux (lm) |
| Tikka XP | 180 |
| MYO XP | 140 |
We look at the popular questions about light-emitting lamps and discuss the myths about circle po-nya-tiya “lu-men”.
Lately we have been hearing questions more and more often:
How many lumens are in an incandescent lamp?
How many lumens are in a light bulb?
How many lumens does the lamp have?
How many lumens are in an LED lamp?
How many lumens are in 1 W of LED lamp?
How to determine the luminous flux of a lamp?
Which LED bulbs Are they similar to incandescent lamps?
Let's try to figure it out. First, let's answer the question: What is a lumen?
Lumen– this is a unit of measurement of the luminous flux of a light source; in our case, the light source will be an LED lamp, an incandescent lamp, the LED itself or any other lamp.
We have prepared a comparison table of the ratio of luminous flux (lumens) to lamp power (W) for LED lamps, incandescent lamps and fluorescent lamps.
|
incandescent lamp, |
Fluorescent Lamp, |
LED lamp, |
Luminous flux, Lm |
| 20 W | 5-7 W | 2-3 W | About 250 lm |
| 40 W | 10-13 W | 4-5 W | About 400 lm |
| 60 W | 15-16 W | 8-10 W | About 700 lm |
| 75 W | 18-20 W | 10-12 W | About 900 lm |
| 100 W | 25-30 W | 12-15 W | About 1200 lm |
| 150 W | 40-50 W | 18-20 W | About 1800 lm |
| 200 W | 60-80 W | 25-30 W | About 2500 lm |
As can be seen from the table, on average, LED lamps are 10 times more efficient than incandescent lamps, and 2 times more efficient than fluorescent lamps.
It is worth noting that the LED, and therefore the LED lamp, emits directional light, unlike incandescent and fluorescent lamps, and this means that the direct illumination from the LED lamp will be higher. Using LED lamps As a spot lighting, the efficiency of such lighting will be higher compared to analogues.
How many lumens are in a 1W LED light bulb?
The luminous flux of modern LEDs varies from 80 to 150 Lm per 1 W. This is due to differences in cooling systems and the current-voltage characteristics of the LEDs themselves.
For experimental LEDs, the luminous flux can reach up to 220 Lm/W, but in practice, lamps with such indicators are not yet produced.
How to determine how many lumens are in our light bulb or lamp?
The luminous flux is indicated on the box or in the product specification. You can also use the comparison table above.
If we want to determine it ourselves, then we need to use a lux meter and determine the illumination at each point in the room. Lux is the ratio of the number of lumens per illuminated area (1 lux - 1 lumen per square meter). The total luminous flux produced by an isotropic source with a luminous intensity of 1 candela is equal to 4π lumens.
What is luxury?
Lux is a unit of measurement of illumination. Lux is equal to the illumination of a surface area of 1 sq.m. with a luminous flux from a source of 1 lm.
In practice, the main value is the illumination indicator on the working surface, measured in Lux (Lux) using a special device - a lux meter. Moreover, the illumination of working surfaces and premises for various fields of activity must comply with state standards specified in SNiP 05/23/2010.
How many lumens are in a lamp with a DRL lamp, Dnat and LEDs?
The lamp, unlike a lamp, has an optical system for more efficient use of the light flux. In cheap lamps that do not have special reflectors and high-quality diffusers, the luminous flux when using powerful DRL and Dnat lamps is significantly lower and can drop to 50-60% of the total luminous flux of an individual lamp, while in LED lamps with a more directional luminous flux, these losses will be significantly less - up to 5% depending on the optical system.
| Lamp with DRL lamp | Lamp with Dnat lamp | LED lamp | Luminous flux, Lm |
| 125 W | 70 W | 30-40 W | About 3,500 lm |
| 250 W | 100 W | 40-60 W | About 8,000 lm |
| 400 W | 150 W | 80-120 W | About 12,000 lm |
| 700 W | 250 W | 140-160 W | About 20,000 lm |
| 1000 W | 400 W | 180-200 W | About 30,000 lm |
*approximate ratios based on calculations in the Dialux program.
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