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Incandescent light bulbs are officially banned in the U.S. (www.digitaljournal.com)
submitted 3 years ago by [M, B] to c/technology@lemmy.world
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Incandescent light bulbs are officially banned in the U.S.::America’s ban on incandescent light bulbs, 16 years in the making, is finally a reality. Well, mostly.

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[–] 11 points 3 years ago (1 child)

Yeah, many of those christmas lights use pulse width modulation to control brightness and it is very noticeable. I hope that gets changed over for an analog voltage dimmer soon.

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  • [–] 5 points 3 years ago (1 child)

    Also, cheap ones run directly on AC, so they flicker at 60 Hz (50 in Europe) because the current is only flowing for half the cycle.

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  • [–] 1 point 3 years ago (1 child)

    How do high-end home LEDs get around this? Do they have a battery that caches the current between cycles?

    When my wife and I bought our place, we renovated and made all lights LED. The overheads in the living room and kitchen are quite bright and steady, so they must avoid this somehow.

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  • [–] 6 points 3 years ago (3 children)

    A bridge rectifier flips the negative current to positive, so instead of a sine wave you get a series of humps. Then a capacitor acts as a battery like you describe to smooth out the dip between humps.

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  • [–] 3 points 3 years ago (1 child)

    There are half wave rectifiers and full wave rectifiers. The former only converts the positive AC to DC and shuts off for the negative half (causing flickering). The latter will convert both positive and negative halves to DC and don't flicker.

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