Empirical characterization of flicker in dimmed commercial LED lamps

In this work, a system for the empirical characterization of flicker effects in dimmed LED lamps is presented. Flicker refers to an undesired low-frequency fluctuation in the intensity of the LED lamp, which can eventually be perceived by the users. Three different off-the-shelf LED lamps and three different types of dimmers were tested. A low-frequency version of the so-called Modulation Depth DM was measured while varying the duty cycle δ for each lamp and dimmer combination. A survey with 100 volunteers was also collected, on their perception of flicker when varying δ for certain dimmer/lamp combinations. The objective was to correlate the measured DM, dimmer and lamps, with the flicker perceived by potential users. In addition to these measurements, the light intensity curve I(δ) was measured for all the lamps and dimmers, and a first test was conducted using a small capacitor in parallel with a test LED lamp to mitigate flicker effect. Preliminary conclusions are presented at the end.