I'm trying to take the voltage output from a 3.5mm audio jack and have it light up an LED according to it's voltage. I was going to attach the left audio cable to the base of a 2222n transistor which would act as my amplifier to trigger the LED to light. Unfortunately, the voltage reading off the wire is like .2 or .02 and isn't high enough to trigger the flow. Is there any way to increase the voltage to trigger the transistor or would I have to use a transformer of some sort (or an op amp??)