[5.9.9.1] A measure of the cyclic variation in output of a light source, taking into account the waveform of the light output. It is the ratio of the area under the light output curve that is above the average light output level to the total area under the light output curve for a single cycle.

As an example, Figure 4 shows a curve of the light output variation from a fluorescent lamp during each cycle, with the method of calculating the flicker index and percent flicker.

Figure 4

Figure 4

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