percent flicker vs flicker index-difference between percent flicker,flicker index

This page compares percent flicker vs flicker index and mentions difference between percent flicker and flicker index measurement.

Definition: As per DOE flicker is defined as "Variation of light output over time". Moreover it states that "all the light sources have flicker to certain degree".

It leads to many health issues such as migraines, headache, Headaches, fatigue, eyestrain, impairment of visual performance etc. The person who perceives flicker will feel annoying and/or distracting.

Flicker is caused due to fault in LED software driver, environmental issues, power supply and/or loads connected with LED/LED Array. The figure-1 depicts one cycle of light output.

percent flicker

The percent flicker or percentage flicker is expressed as per equation-1 above. It uses 0 to 100% scale. It is more well-known and commonly used parameter. It is referred as peak to peak contrast or Michelson contrast.

flicker index

The flicker index is expressed as per equation-2 above. It uses 0 to 1.0 scale.

Light flicker analyzer instrument is used to measure percent flicker and flicker index as described above. Neither of these parameters account for frequency.

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