LED AND decibel gauges

Discussion in 'General Electronics Chat' started by Bobber, Feb 25, 2008.

  1. Bobber

    Thread Starter New Member

    Feb 25, 2008
    1
    0
    I built a15 L.E.D display With two decibel gauges for my sons computer that I removed from an old reel to reel taperecorder. the needles on the gauges move a little bit but not enough to make it look cool.should I use transistors to boost the output to the gauges I do not want to burnup the gauges (conn to speaker output) power supply is 12vdc 200 mamp
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    5,072
    6
    You could use an op amp with variable gain.

    http://www.allaboutcircuits.com/vol_3/chpt_8/5.html

    By using a potentiometer as the feedback & input resistor portion, you can turn the gain up slowly. Then you can put a drop of nail polish on the potentiometer to lock it in place.
     
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