LED's flickering to music

Discussion in 'General Electronics Chat' started by Booocubs, Feb 13, 2012.

  1. Booocubs

    Thread Starter New Member

    Dec 11, 2011
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    How does this circuit look,do you think it will work? The LED's in this picture are Blue 5mm LED, 6000mcd, with a 3.3Voltage drop and a max continuous current of 30mA.. max peak current of 70mA.

    [​IMG]

    My hope is that the LED's are powered by the 12v, but only turn on and is bright when the music plays hence the and gate. Your thoughts suggestions and comments please? :X
    Thanks;
    -Josh

    :confused::confused::confused::confused:
     
  2. Wendy

    Moderator

    Mar 24, 2008
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    The AND gate probably won't work. You will need drivers for that, something that can handle the relatively large amount of current required.

    Google Color Organ.

    Or, you can try the circuits in my article.

    LEDs, 555s, Flashers, and Light Chasers
     
  3. Audioguru

    New Member

    Dec 20, 2007
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    Music is AC but the gate works only with DC so the music will blow up the gate.
    The load for the gate is 252mA. Nobody makes a gate that powerful.

    Why not use a power amplifier IC to drive the LEDs?
    You can bias the amplifier so its output is low with no signal then it amplifies the peaks of the music which lights the LEDs.
     
  4. Booocubs

    Thread Starter New Member

    Dec 11, 2011
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    Now AudioGuru, I'm still a beginner at electronics; so sorry for my ignorance.

    This power amplifier IC you are talking about, may you link me to one please?
    Also, when you say bias the amplifier, would I need the 12v power supply still?

    OFF TOPIC;
    Is there an android APP for these threads or mobile notifications? I would love it if there were, thanks :)
     
  5. Wendy

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    Mar 24, 2008
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    <shrug> There is something out here, I'm not sure of the details.

    To do what you want to do you are going to have to learn some electronics, no way around it I'm afraid.

    Chapter 12 on the link has a couple of circuits showing how it is done. It is under the subtitle "Fire!"
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    Here is my circuit of a powerful audio amplifier IC that is biased so its output is low with no signal. The signal causes its output to go high which lights up to 750 ordinary 20mA LEDs.

    Since the circuit rectifies the signal then the LEDs are lighted only half the time which makes them appear a little dimmed. Then the strings can be 30mA and a maximum total
    of 495 LEDs may be used.

    Of course the amplifier needs a heatsink.
     
  7. Booocubs

    Thread Starter New Member

    Dec 11, 2011
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    I like the looks of this circuit, It looks exactly like what I'm trying to accomplish.
    Just a few really quick questions though;
    1) as seen in C5, (Capacitor 5); the thick black bar at the bottom, is that referring to ground?
    2) as seen only in C5 and C6, why are both sides of the capacitor filled in black, and in other C's, only one side is filled in.
    3) where would I put the heat sink into the circuit?

    I'm assuming that "IN" Refers to the audio input.

    Thank you guys so much for all your help. It's people like you guys that make me want to get more and more into electronics; which is what I want to make into a career.. so thanks :)
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    Europeans sometimes draw a polarized electrolytic capacitor as an open box as the positive wire and as a black bar as the negative wire.
    They draw a film capacitor (it is not polarized) as two black bars.

    The heatsink is bolted to the metal tab on the IC with a thin layer of thermal grease in between. The size and number of fins on the heatsink must be calculated.
     
  9. Booocubs

    Thread Starter New Member

    Dec 11, 2011
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    Thank you! Is there a formula to calculate the correct heatsink?
     
  10. Audioguru

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    The datasheet for the TDA2050 spec's that its thermal resistance from its chip to its case is 3 degrees C per Watt and its max allowed chip temperature is 150 degrees C. Thermal grease has a thermal resistance of about 0.5 degrees C per Watt. If you are not in a jungle then the ambient temperature is a max of 30 degrees C. The datasheet shows a graph of the Total Power Dissipation (heating) for various output powers.

    The datasheet has a section that talks about heatsinks. It shows a graph of the maximum allowed dissipation (heating) with a perfect heatsink (maybe with a huge heatsink and a high speed fan) and 3 available heatsinks. The arithmatic to calculate a heatsink is simple. Catalogs describing heatsinks are available.
     
  11. Booocubs

    Thread Starter New Member

    Dec 11, 2011
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    Thanks :) And one more quick question; in your diagram, where your audio input is, that little cross section, are all those connected, or just the two resistors? There's no junction so I'm just making sure. Thanks!
     
  12. Audioguru

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    I simply modified the horrible schematic in the Italian datasheet. Now I fixed the schematic to make it clearer.
     
  13. Booocubs

    Thread Starter New Member

    Dec 11, 2011
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    You're a god among men, Audio :)
     
  14. Wendy

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    Mar 24, 2008
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    He knows. :D :p
     
  15. Audioguru

    New Member

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    It is too soon to worship me.:)
    I have never seen a TDA2050 amplifier IC.
    You can worship me after you build the circuit and see it working.
     
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