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Thread: How to turn half wave LEDs to full wave LEDs

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    Official Lurker dariansdad's Avatar
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    Default Re: How to turn half wave LEDs to full wave LEDs

    My take is Achy and Breaky are not even words and that song makes me sick too.

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    New Member Micah Wood's Avatar
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    Default Re: How to turn half wave LEDs to full wave LEDs

    just for the record, 60Hz AC means 60 up AND down parts of the sine wave. you will never see a 30Hz flicker in your christmas lights unless you cut the frequency in half. I keep seeing this 30Hz crap all over the forms and its dead wrong! Ill prove it to you. Hz = Cycles per second. 1 cycle is 360 degrees around the unit circle from which the Sine function is derived. so in going around the unit circle (starts at 0 degrees) we go from quadrant I to IV consecutlively. that means you are positive on the y-axis for the first 180 degrees (quadrant I and II) and negative on the next 180 degrees (quadrant III and IV). so in 60 cycles per second, we and 60 positive parts and 60 negative parts. if you drew it out on paper you would count 60 peaks in one second. when you Full wave rectify, you turn the negative parts into positive making 120 peaks of positive polarity.

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    Professional Net Lurker Jack Stevens's Avatar
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    Default Re: How to turn half wave LEDs to full wave LEDs

    you're correct there; a 1/2 wave LED string will turn itself on 60 times a second, and be off for slightly over 50% of the duty cycle. They aren't glowing the entire conducting side of the sine wave; there has to be sufficient voltage for the chemical composition of the LED to fluoresce.

    Putting in the bridge rectifier increases that duty cycle from less than 50% to just under 2x the original duty cycle; AC input has to exceed the forward conduction voltage of the bridge rectifier diodes.

    When it comes down to it, the 8 cents it cost me for the diodes to make up the bridge, the 2 cents in solder, and 15 cents in hat shrink means I can see the lights without developing an eye strain headache, something I'm very prone to, as are several other members on here. Those that aren't negatively impacted by the (to some people) "imperceptable" flicker still agree that the string seems brighter. It's not glowing any brighter, it's just glowing during a greater portion of the input AC sine wave; the human eye and brain perceives it as being brighter.

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    Professional Net Lurker Jack Stevens's Avatar
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    Default Re: How to turn half wave LEDs to full wave LEDs

    you're correct there; a 1/2 wave LED string will turn itself on 60 times a second, and be off for slightly over 50% of the duty cycle. They aren't glowing the entire conducting side of the sine wave; there has to be sufficient voltage for the chemical composition of the LED to fluoresce.

    Putting in the bridge rectifier increases that duty cycle from less than 50% to just under 2x the original duty cycle; AC input has to exceed the forward conduction voltage of the bridge rectifier diodes.

    When it comes down to it, the 8 cents it cost me for the diodes to make up the bridge, the 2 cents in solder, and 15 cents in hat shrink means I can see the lights without developing an eye strain headache, something I'm very prone to, as are several other members on here. Those that aren't negatively impacted by the (to some people) "imperceptable" flicker still agree that the string seems brighter. It's not glowing any brighter, it's just glowing during a greater portion of the input AC sine wave; the human eye and brain perceives it as being brighter.

  5. #20
    Havin fun ! kidcole's Avatar
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    Default Re: How to turn half wave LEDs to full wave LEDs

    Quote Originally Posted by Micah Wood View Post
    just for the record, 60Hz AC means 60 up AND down parts of the sine wave. you will never see a 30Hz flicker in your christmas lights unless you cut the frequency in half. I keep seeing this 30Hz crap all over the forms and its dead wrong! Ill prove it to you. Hz = Cycles per second. 1 cycle is 360 degrees around the unit circle from which the Sine function is derived. so in going around the unit circle (starts at 0 degrees) we go from quadrant I to IV consecutively. that means you are positive on the y-axis for the first 180 degrees (quadrant I and II) and negative on the next 180 degrees (quadrant III and IV). so in 60 cycles per second, we and 60 positive parts and 60 negative parts. if you drew it out on paper you would count 60 peaks in one second. when you Full wave rectify, you turn the negative parts into positive making 120 peaks of positive polarity.
    Good point. You are right ! The flicker that people see is the dead half of 60 cycles, when the LEDs are not fully rectified.
    Thanks,

    Denny Cole
    https://www.facebook.com/groups/Cole...ristmasLights/

    Back to Work <unretired> so I went Static in 2017. Planning xLights when I retire <again>. Maybe 2019 ?

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  6. #21
    Member Chris Gebhardt's Avatar
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    Default Re: How to turn half wave LEDs to full wave LEDs

    Ok, I got some of the boards from Denny and am assembling the first one. The boards have H & N which I assume is hot and neutral (AC Side) and the other side is + & - (the DC side). So I have it wired up, the male on the AC side and female on the DC side. Well I may not be the best solderer in the world so I want to test it first before I plug it and it go's poof. Any way to make sure it is correctly wired before you fry the board?

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