VU Meter

Discussion in 'General Electronics Chat' started by denno, Jul 1, 2008.

  1. denno

    Thread Starter Active Member

    Jul 1, 2008
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    I was just wonderng how I could go about creating a VU meter using the LM3915, but being able to use a switch, so I can either have constant power to the LED's (so they're always on), or have the signals from the chip (so they ac like the VU Meter).

    I was thinking of circuit, where the power goes into a switch, and then into the chip, or to another wire which goes straight to the LED's. Then each of the LED's will have a connection on ita onde from the chip and the normal power wire. Would this be alright to set up this way? If I haven't explained it too well, let me know and I'll whip together a diagram. Infact I will just do a diagram anyway and post it in a rely in a few minutes...

    Thanks in advance.
     
  2. denno

    Thread Starter Active Member

    Jul 1, 2008
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    Ok I am well aware that I can't connect the power straight as have done in the picture, but this is just a very generalized picture, just to give everyone an idea of what I mean.
    The yellow is power to the switch. The red takes the power to the LM3915 chip, and the blue takes the power straight to the LED's.
    Will this work?

    [​IMG]
     
  3. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    It would be easier just to apply a DC voltage at the input to the 3915 to give a full-scale reading. Put a resistor beween the output of the preceeding stage and the input to the 3915 to prevent excessive current flowing back into the output stage of the driver.
     
  4. denno

    Thread Starter Active Member

    Jul 1, 2008
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    would this still allow me to change between having the 3915 work as it's made to, displaying a VU Meter, and havingthe LED's just constantly on?
     
  5. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Yes, just apply the DC to the input via a switch.
     
  6. denno

    Thread Starter Active Member

    Jul 1, 2008
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    ok thankyou mate :). much appreciated
     
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