OpAmp+Audio from iphone, blinking leds?

Discussion in 'The Projects Forum' started by secmeton, Sep 30, 2012.

  1. secmeton

    Thread Starter New Member

    Sep 30, 2012
    Hello I am a beginner to electronics, I am taking my first electric circuit analysis class in college. I was wondering if I can amplify the output of an iphone with an opamp in order to make some leds to blink to the music. If anyone can help me to accomplish this I would really appreciate it. I need to know if I can do this at all, what type of opamp and how much is the output of the iphone in volts(AC I supposed). I supposed I would use an opamp in a non inverting setup.
  2. Audioguru


    Dec 20, 2007
    An opamp has a maximum output current of only 20mA which is enough to light one LED or if the power supply voltage is high enough then it can light a few LEDs in series.

    An emitter-follower transistor can be added to the output of the opamp to deliver more current to light more LEDs.

    You can use a trimmer vatiable resistor to set the gain of the circuit to whatever is good.