9/25/2023 0 Comments Equivalencia candela lumenIf you look at LEDs, especially high-brightness LEDs, you may notice that they have a high luminous intensity (in candela or milli-candela, mcd) and usually have a narrow corner angle. Similarly, LEDs with a wide vertex angle tend to have a relatively low light intensity. The same applies to halogen spotlights with a reflector: those with a narrow-beam reflector have a higher candlepower than wide-beam spotlights with the same power. The angular span of the candela is expressed in steradian, a unitless measure (this is like radians for angles in two-dimensional space, but they are not the same). A steradian on a sphere with a radius of one meter gives a surface area of one m 2 . A complete sphere measures 4π stereoradians. This is because the screen B covers the same angle as screen A. To facilitate illustration, in the image above the three dimensions have been reduced to two. In this image, screen B would capture exactly the same amount of light rays (emitted from the light source) as screen A, provided that screen A was removed so as not to obscure screen B. The candela measures the amount of light emitted in the range of an angular (three-dimensional) span. Since light intensity is described in terms of an angle, the distance at which you measure this intensity is irrelevant. The candela (cd unit) has its origin in the brightness of a “standard candle”, but has received a more precise definition in the International System of Units (SI), and at that time the unit was also called a “candle” or “candle”. More importantly, this knowledge will ensure that your lighting supplier does not mislead you, as they may try to convince you of the advantages of a lighting fixture by citing impressive lumens or candela numbers that are not relevant to your needs. Knowing the difference between lumens and candela will help you choose lighting fixtures that suit the needs of your workplace Lumens and candela are units of measurement for lighting, but they measure different aspects of a lighting fixture. Step 3: Example: An LED luminaire produces 1.5 candela at a corner angle of 70 °, how many lumens does it produce? All you have to do is replace 1.5 cd and 70 ° C in the conversion formula, which will give you: 1.7lm. Step 2: Enter the candela and degrees into the formula: lumens = candela × (2π (1 – cos (degrees / 2))) . Step 1: Obtain the candela and the vertex angle in degrees of the light source. (These values are in catalogs and the internet). In other words, the formula to convert from candela to lumen is as follows: Steps to convert from candela to lumen When making the replacement of the formula of the steradians (2) in the formula of candela to lumen (1), we have the following: To convert from candela to lumens, the value of candela must be multiplied by the angular interval of the light source in steradians, as shown in the following formula (1): Where, is the symbol of the lumens to find and, is the symbol of the candelas, while, it is the symbol of the steradians that are defined by the following formula (2): Examples of how to convert from candela to lumen
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