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    Lighting and Life

    ekonomik-omur

    Economic Life

    To explain this term in more detail and in a more understandable way; For example; While there are statistically sufficient lamps in a lighting system, after 100 hours of use, the luminous flux of these lamps becomes unusable and therefore 30% of the luminous flux is lost. This lost time is called economic life.

    Life Expectancy

    In a lighting system with a number of lamps that can be evaluated statistically, the period in which 50% of them become unusable in normal standards is called the average life. This period varies according to the temperature of the junction of the LED chips. Therefore, if the temperatures of the LEDs driven at high current are high, their lifespan decreases.

    This term, called LM 80-08, is a standard that does not define the decrease in luminous flux of LED light sources over time. This term requires LED light source manufacturers to provide luminous flux measurements for a minimum of 6000 hours. Therefore, it is recommended that luminous flux measurements be made by taking data every 1000 hours for a minimum of 6000 hours, ideally 10000 hours of use. For periods longer than 10000 hours, the TM 21-11 standard is used. This standard includes the long-term estimation of the data obtained from measurements made according to LM 80-08. These recommended values ​​​​estimate the time until the luminous flux decreases to 70%, i.e. the average life. The life estimation made when an example LED chip is driven at different current levels is given on the side.

    Color Rendering Index (Ra)

    The ability to distinguish colors of objects illuminated by light sources is called the "color rendering index". The color rendering index (CRI) is used to compare the color characteristics of these different light sources. The color rendering index is indicated by "Ra" and is unitless. Its value varies between 0 and 100. For example; If the color rendering index of the light source has a maximum value of 100, we can say that it is (Ra=100). This means that the spectrum of that source is the same as the reference source.

    Armatures

    Armature systems are generally lighting systems that are used to control the distribution of light from light sources, to give it the desired shape,protect electrical circuits against physicaleffects,reduce glare, and to meet the need for aesthetic feelings and comfort. These lighting systems are the most important factorin order to make “lighting calculations”.

    Light Dispersion Surfaces and Curves

    It is the geometrical surface of the light intensity in different directions that a lighting fixture reflects in space. These surfaces are called the “light distribution surface” of the fixture. In order to obtain the light distribution, measurements must be made in infinite directions. Therefore, since it is more practical, light distribution curves are given in a table with various planes passing through the lighting fixture. In this way, lighting calculations are made correctly. Light distribution curves and light intensity tables are given as 1000 lm (cd/klm). For this reason, according to CIE, the light distribution curves of the fixtures can be given in three different planes as A, B and C.

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