Hey guys, I am working on a project which requires me to use a BNC coaxial cable and an ardunio. I cut the metal off of one end of the BNC coaxial cable to plug directly into the ardunio analog ports but I'm not sure if these two wires I have now are power and ground or just signals. Please help!...
It runs from an amplifier. Basically I'm trying to amplify a signal from a microphone and connect it to ardunio.
So what does the cable connect to?
Yeah, it matters what it's connected to, like, bigtime. Because the other device could have them connected to whatever the hell it wants.
The braided metal sheath is almost certainly ground.
Hi,
Hi, what is your electronics, programming, arduino, hardware experience?
Is this a school/college/university project?
What is the application?
Tom.... 
It runs from an amplifier. Basically I'm trying to amplify a signal from a microphone and connect it to ardunio.
University project, proficient in those things listed but not I wouldnt say advanced
Hi
Audio or what frequency, what amplitude, the arduino analog ports are only 0 to +5V?
Model arduino?
Tom....
BNC is a type of plug, not a type of cable.
Once you have cut off the plug, the type of the plug has become rather irrelevant. What matters, is what type of cable it is.
If it is a simple kind of coaxial cable, it might have two conductors. One in the middle, one that looks like a hollow cylinder of foil, or woven, wrapped around it.
Assuming the voltage is less than 5 volts, the signal would be the center wire, and the ground would be the other conductor.
I would suggest trying to determine the voltage, first. Connect it to an oscilloscope.
Get a BNC socket and a microphone preamp module.