The Indium gain is not as dramatic as in 119D test or perhaps other ceramic based LEDs. Because E17A/E21A has fragile phosphor layer and use polymer base. The phosphor layer burns way faster than ceramic base LEDs before the actual die cooked. I only did controlled test on 4pcs E21A to save time. The rest of the R70 tested at 2A starting point (60 seconds stops for current ramping) just to cross check/validate my finding. The controlled test done with 3 minutes for each steps. This what makes the burnt patterns looks different. Beyond peak current, E21A phosphor layer slowly degrade and burns at several hottest points.
- Clemence