Slow-Motion LED

yaggy

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Took some slo-mo video of an LED
and an incandescent flashing on/off
during attract mode on a dr. dude. (1/6th speed)



This reveals two main things:

1. LEDs go immediately on and off, incandescents rise and fall.

This results in those "traveling" strips of flashing lamps appearing
to have a much different effect from one another.

2. LEDs actually strobe very quickly, incandescents have a steady burn.

Strobing is said to cause eye strain, fatigue.
There is some fluorescent ambient light in the
video too, which strobes.

There's not much love out there for the burny-hot
juice-sucking short-life-having tungsten lamps
but in certain ways they're still the cadillac of lighting.
 
download3.md.jpg
 
Yeah I mean LED operating frequency. The flicker rate is particularly bad because of the AC power source obviously. Can we throw a constant current driver into the mix perhaps?
 
LEDs have a rapid on/off time. Orders of magnitude faster than bulbs. To get them to look and act like bulbs, you need to modulate them, the way the LEDOCD does. There's no simple solution.



I thought that was because of AC power? Using DC power eliminates the flicker because there's no wave.
 
I thought that was because of AC power? Using DC power eliminates the flicker because there's no wave.



LEDs still turn on and off quickly when power is applied/removed. You may see less flicker once the bulb is on, but in terms of the amount of ramp-up time it takes to go from off to on, they're all fast, because the nature of how they're made (i.e., a tiny piece of silicon, versus a tungsten filament that gets physically hot, and takes hundreds of milliseconds to warm up).
 
I thought that was because of AC power? Using DC power eliminates the flicker because there's no wave.

Feature lamps are done by a lamp matrix. That means they still get strobed. LED bulbs with a cap inside them may help there.

General Illumination lamps are typically AC. Rectified LEDs will flicker at 120hz (okay, but still noticable). Non rectified LEDs flicker at 60hz (horrible).

You can use a switching dc supply and use it for the General Illumination. I did so for my Williams F-14. Worked out pretty well to eliminate the 120hz strobe effect I get when the ball travels fast.
 
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