Simple Color Organ

Discussion in 'General Electronics Chat' started by Uzair Tariq, May 15, 2015.

  1. Uzair Tariq

    Thread Starter New Member

    May 15, 2015
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    Below is the schematics of a simple color organ.
    If anybody doesn't know what a color organ is kindly see the following links.

    www.youtube.com/watch?v=wJlglHS2w74
    www.youtube.com/watch?v=Yd3hzYAJzOo

    I was just wondering if anyone could explain me the working of this project.
    I really wanted to know how these simple electronic components work together
    to flash LED's listening to the music input.
     
    Last edited: May 15, 2015
  2. Uzair Tariq

    Thread Starter New Member

    May 15, 2015
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    Schematics
     
  3. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Isn't that, basically, what was just explained in the video? The details of how these components (resistors, capacitors, diodes, and transistors) work can be found in any introductory electronics course.
     
  4. Uzair Tariq

    Thread Starter New Member

    May 15, 2015
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    Thanks for the reply!
    Actually I'm familiar with the working principle of transistors and diode I'm not getting that how the frequencies are being filtered by this circuitry.
     
  5. Dodgydave

    Distinguished Member

    Jun 22, 2012
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    each led transistor has a filter comprising of the resistor and capacitors, the capacitors alter their reactance with the frequency of the signal,( higher frequencies = lower reactance) so allowing the respective leds to flicker,
     
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  6. Uzair Tariq

    Thread Starter New Member

    May 15, 2015
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    Thanks !
    And how transistors are playing their role in the circuit?
     
  7. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Q1 is a buffer amplifier to prevent the rest of the circuit from loading down the source. Q2, Q3, and Q4 each act as a current amplifier. The louder the music signal at the base, the more current goes through the LED string, making them brighter. Notice that the capacitors and resistors at each base are different. These arrangements acts as a highpass filter, bandpass filter, and lowpass filter, so each transistor responds to a different portion of the music spectrum.

    Cute little circuit.

    ak
     
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  8. garumel

    New Member

    Jul 24, 2011
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    Hi everybody, in reading this thread it got me to think about another not so simple color organ that I see on the net. I was wondering if some of you skilled people could look at the
    schematic for this one and tell me if it will work. I am not sure about the PNP transistors, are they backwards, are they used as a diode, or are they just in reverse mode.
    I don't have the skill to understand the circuit that well. Thanks in advance.
    EDIT sorry I can't seem to send attachment, but the link is Discrete LED color organ @
    electronicpeasant.com
     
    Last edited: May 19, 2015
  9. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Yes, the three 2SA1175's are upside down.

    ak
     
  10. garumel

    New Member

    Jul 24, 2011
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    Thanks for the reply AK, I have some electronic skills, and have made some LED projects and I would like to make this one too. I ask the question because I have heard of reverse active mode used in some circuits, and just wanted to know how the PNP's were used in that circuit, and what is their purpose. So if they are just shown in the schematic backwards, then I just reverse the emitter and collector, right? Just asking as I am basically self educated in electronics, and still learning, and I do a lot reading and lurking on sites such as AAC. I learn a lot just from reading answers to other members questions that are similar to mine. Thanks again.
     
  11. AnalogKid

    Distinguished Member

    Aug 1, 2013
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    Yes, reverse C and E. Installed correctly, each PNP acts as a combination signal rectifier and voltage/current amplifier. When the signal at its base goes positive, the transistor turns off and the LEDs start to dim as the capacitor on its collector discharges. When the audio goes negative the PNP turns on, pumping current into the cap and the string of LED drivers. Since each successive driver is separated by a diode, more of them turn on as the audio gets louder.

    ak
     
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