I am doing some study on the frequency of electrical supply. I need to do the analysis on MATLAB. I want to record the electrical signal as an audio file in my laptop.
As I am a beginner working with 220V mains, I have a fear of busting my soundcard . I need expert advice on how I can develop my circuit and what type of protective measure should be taken.
So far my idea is to use a transformer of 220/12 volts then using a voltage divider circuit. But I actually don't know what is the limit of Line-In voltage for PC soundcard. Up to what extent should I attenuate my signal?