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Varying frequency of an LED drive circuit

  1. Feb 10, 2017 #1
    Greetings. How would I go about finding a way to use an audio signals frequencies to control the positive connection on a 12v dc led circuit? In other words, have the visual effects you get hooking up a dc led strip to an amplifier, but instead controlling the dc positive output to the strip from the constant 12v power supply using an ac audio signal as it's control? Thanks
  2. jcsd
  3. Feb 10, 2017 #2


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    Staff: Mentor

    Welcome to the PF.

    What do you want the LED brightness to do in response to the audio? Get brighter with louder audio? Flicker with the audio sounds? Show a bargraph of loudness as the audio gets louder and softer?
  4. Feb 10, 2017 #3
    I would first consider Using a operational amplifier config. As for our good
    friend berkman mentioned for any of the 3 mentioned needed effects, using of course the appropriate peripheral outboarded components
  5. Feb 10, 2017 #4
    I want them to retain full operating brightness but flicker at the rate the low end frequency it's recieving via audio signal
  6. Feb 10, 2017 #5


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    Staff: Mentor

    So you'll want to select the low-end frequencies (filter circuit), rectify and smooth, and use the result to vary the current supplied to your LEDs. This sort of thing was (still is?) a popular hobby circuit. Google: "color organ circuit".
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