relative amplitude of the periodic fluctuation of the luminous flux as measured by the ratio of the difference between the maximum and the minimum luminous flux to the sum of both these values
NOTE 1 – This ratio is usually expressed in per cent and is then known under the expression per cent flicker which, however, should be deprecated.
NOTE 2 – Another means sometimes used by the lighting industry to characterize the fluctuation in light output is flicker index, which is defined by the ratio of two areas deduced from the diagram representing the variation of the instantaneous flux over a period of time; the area of the diagram above the average value is divided by the total area under the curve (this total area is
the product of the average value and the given period of time).
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