LED AND decibel gauges

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

  1. Bobber

    Thread Starter New Member

    Feb 25, 2008
    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
    You could use an op amp with variable gain.


    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.