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Thread: PWM - What is it, How does it work and how to detect it.

  1. #121

    Default Re: PWM - What is it, How does it work and how to detect it.

    hi
    everyday I learn something new Flashlights are like Ecstasy
    I need PWM driver, is there any PWM driver comparison to their efficiency? price? and where to buy?

    Edit: I've found this, is another greate post
    http://www.candlepowerforums.com/vb/...ttery-voltages
    Last edited by KARADENIZ; 12-19-2013 at 06:30 AM.

  2. #122
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Great find there! I had to bookmark it, thanks.
    Cataract, Shiny things specialist.
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  3. #123

    Default Re: PWM - What is it, How does it work and how to detect it.

    Cataract, thank you for this very informative post! Besides giving me a good understanding of what PWM is and why it is used, it helped me to understand why some of my flashlights have a much longer run time on low than others, when low is basically the same lumen rating with the same batteries.

  4. #124

    Default Re: PWM - What is it, How does it work and how to detect it.

    Great explanation! I had a general idea but this really clears things up.

  5. #125
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Thanks guys, I'm really glad I could put this clearly enough to help others. Comments like these really make me feel it was worth more than just the time I spent doing it
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  6. #126

    Default Re: PWM - What is it, How does it work and how to detect it.

    😄.w💩!#.!💩😋..w

  7. #127
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Erm... I don't know what's going on here... I thought this was a bot posting until I checked your other posts. Need any help?
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  8. #128
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    Default Re: PWM - What is it, How does it work and how to detect it.

    I'm interested too.

    Bill

  9. #129

    Thumbs up Re: PWM - What is it, How does it work and how to detect it.

    That is amazing . The light picture is a excellent description .That i would like to give it a try.

  10. #130
    Flashaholic* RI Chevy's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Welcome to the Forum!

  11. #131
    Enlightened xelario's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    "Your eyes are a little like tiny cameras that take about 24 pictures per second." This should be removed.

  12. #132
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by xelario View Post
    "Your eyes are a little like tiny cameras that take about 24 pictures per second." This should be removed.
    It has been estimated that the brain (yeah, not the eyes) processes about 24 frames per second. I'm not sure if there have been more recent studies into this, but the origin of this idea is that movies that showed less than 24 frames per second in the very debut of cinema made a lot of people regurgitate (to use the more polite way of saying what I have read). By experimenting, they had concluded that 24 frames per second kept the audience in their seat while keeping the length of reels as short (therefore less costly) as possible.

    This number is definitely debatable, but there is definite evidence that we cannot perceive more than a certain number of "pictures per second" if we compare to how movies are displayed on screen or on TV's or computer monitors. I did phrase it "a little like tiny cameras" and "about 24 frames per second" on purpose.
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  13. #133
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by Cataract View Post
    It has been estimated that the brain (yeah, not the eyes) processes about 24 frames per second. I'm not sure if there have been more recent studies into this, but the origin of this idea is that movies that showed less than 24 frames per second in the very debut of cinema made a lot of people regurgitate (to use the more polite way of saying what I have read). By experimenting, they had concluded that 24 frames per second kept the audience in their seat while keeping the length of reels as short (therefore less costly) as possible.

    This number is definitely debatable, but there is definite evidence that we cannot perceive more than a certain number of "pictures per second" if we compare to how movies are displayed on screen or on TV's or computer monitors. I did phrase it "a little like tiny cameras" and "about 24 frames per second" on purpose.
    The brain can only process about 24 frames per second? Wow. I must be from a different species, then In fact, a lot of people must be. I mean why else would we even have 120Hz monitors? And 144Hz? Madness!
    Why do TV movies at 30fps look different, than cinema 24fps ones? Why did people find The Hobbit's 48fps weird? Why even film and show it at 48 if 24 is all our brains can process? You talk about TV and movies, but never mention games. Maybe you're not a gamer. I am. If my eyes or brain only processed 24fps, I wouldn't have to buy expensive hardware to run games at >60, preferably >100. 30, 60, 100fps - there's a very noticeable difference to me.
    In other words, it's a difficult subject, but neither our eyes nor brain are capped at 24 fps. That's why I think this claim should be removed. For someone who knows absolutely nothing about the subject reading this article would be highly misleading. The eyes don't "take pictures", they provide a continuos stream of data. The brain does not "take those images and assemble them into what we perceive as the continuous movie of our lives".
    Please don't be offended, I hope it doesn't looks like I'm attacking you, I just don't like to see wrong or debatable data being presented as true fact and potentially misleading people in an otherwise good article.
    If I were you, I'd drop the whole paragraph about 24 frames per second, it only adds to confusion. You explained it later: "The lower frequency PWM will be more perceivable to the eyes as a fast strobe effect – remember what it looks like to dance in a club when the only lighting around are strobes? Well, imagine that strobe is even faster, to the point that motion is almost continuous...".

  14. #134
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Around 24 fps is likely where our brains stop perceiving the images as individual pictures, and see them as fluid motion. That doesn't mean we can't perceive things faster than that, but it does seem to be a turning point of some kind. Stop-motion films at 12 fps do not look smooth at all. At 24 fps, we're willing to accept it as real motion.

    My guess it probably has something to do with the amount of time it takes our brains to process an image from our optic nerves. If it takes more than 1/24s, then we just accept it as smooth motion.

  15. #135
    Enlightened xelario's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by WalkIntoTheLight View Post
    Around 24 fps is likely where our brains stop perceiving the images as individual pictures, and see them as fluid motion. That doesn't mean we can't perceive things faster than that, but it does seem to be a turning point of some kind. Stop-motion films at 12 fps do not look smooth at all. At 24 fps, we're willing to accept it as real motion.

    My guess it probably has something to do with the amount of time it takes our brains to process an image from our optic nerves. If it takes more than 1/24s, then we just accept it as smooth motion.
    Again, "likely" is not "definitely". There is a lot to this subject. In the movies, the 24 frames per second look like fluid motion, but in games it doesn't. Because in movies fast motion is blured, while in games it isn't - the same goes with PWM, it's on or it's off. Try looking at a light at 24Hz - I did - it's visibly blinking. Also in the movies the 24 unique frames are not projected at only 24Hz, and so on. 24fps in the movies is not the same as a light at 24Hz PWM.
    My point is, the whole 24fps thing in an article about PWM in flashlights is totally out of place and adds nothing usefull, no flashlight will use 24Hz or similar PWM. And the way it's written now is plain wrong and misleading.

  16. #136
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    Default Re: PWM - What is it, How does it work and how to detect it.

    This is turning into a very interesting discussion that should be had on a completely different thread. Start that thread and I'll meet you there (PM me or link it here). The goal here is not to confuse people who want to learn about PWM.
    Cataract, Shiny things specialist.
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  17. #137
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by Cataract View Post
    The goal here is not to confuse people who want to learn about PWM.
    And that's exactly what you're doing, IMHO... My goal here was not to start a discussion (so I won't start a new thread), but to remove the confusion. Finally you seem to understand, but only see the consequence (discussion) and not the cause (24fps paragraph). Maybe you don't think that text is confusing, misleading and/or wrong and is actually useful for people learning about PWM. Oh well, I did what I could

  18. #138
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Awesome. I always wondered what that picture people uploaded of a light trail meant.

  19. #139
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by radiopej View Post
    Awesome. I always wondered what that picture people uploaded of a light trail meant.
    Quote Originally Posted by Jenifer512 View Post
    Wow. Science is really fantastic. Thanks to all inventors behind this great LED improvement.
    Thanks guys
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  20. #140
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Thank you! I ran into the dark bathroom waving half of my lights right after reading. My girlfriend was very confused.

  21. #141

    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by radiopej View Post
    Thank you! I ran into the dark bathroom waving half of my lights right after reading. My girlfriend was very confused.
    JMHO, but I wouldn't go looking for it .

    http://www.candlepowerforums.com/vb/...=1#post4307784

  22. #142
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    LOL, but it's a great method to find a way to improve one's collection
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  23. #143

    Default Re: PWM - What is it, How does it work and how to detect it.

    well done, thanks for sharing the post,I have no idea about this,but have learnt a lot after reading the post.
    Last edited by feifei; 10-26-2014 at 11:23 PM. Reason: spelling mistake

  24. #144
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Thank you, it is really my pleasure to share the knowledge.
    Cataract, Shiny things specialist.
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  25. #145

    Default Re: PWM - What is it, How does it work and how to detect it.

    Nice work, I must say. Various points discussed here about LED flashlights are genuinely very informative.

  26. #146
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Thank you sir.
    Cataract, Shiny things specialist.
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  27. #147

    Default Re: PWM - What is it, How does it work and how to detect it.

    Thank you. I found this very useful when recently purchasing a Streamlight Protac HL and seeing PWM being mentioned in reviews of the light's low mode.

  28. #148
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Kinda sucks that Streamlight would go the PWM way. Were you able to detect it? Is it really annoying?
    Cataract, Shiny things specialist.
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  29. #149

    Default Re: PWM - What is it, How does it work and how to detect it.

    As a newbie to both LED lights and this forum I much appreciate your description of PWM as it has enlightened me and cleared up a few questions I had regarding PWM.

  30. #150
    Flashaholic* Cataract's Avatar
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    Default Re: PWM - What is it, How does it work and how to detect it.

    Quote Originally Posted by franksr View Post
    As a newbie to both LED lights and this forum I much appreciate your description of PWM as it has enlightened me and cleared up a few questions I had regarding PWM.
    Thank you. There's nothing like knowing my article did what it was intended to
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