When you are tuning your guitar with an electronic guitar tuner, guess what? You are still the real guitar tuner. You have to pay attention and do more than just look for the green light.
Have you ever spent a painstaking moment making sure each string was in perfect tune, only to strum a chord that sounded a little...unexpected? Here's the problem:
You are tuning the right string to the wrong note. Or...the wrong string to the right note.
Either way, you must know the name of the string you're tuning, otherwise you'll be in trouble.
Did you know it's possible to tune a G string all the way up to A? it is. It's an excellent way to break it.
Here are the names of the strings:
Just make sure that the letter that appears in the little window on your electronic tuner is the same as the name of the string you're tuning, and you're golden!
Some guitar tuners, such as the Korg GA-30, only have these six notes to choose from.
However, beware of chromatic tuners like the Korg CA1. These are versatile tuners. However, they can recognize twelve different notes, which increases the likelihood of mistakes for the beginner.
You can file this post under "duh," but if you run into trouble tuning your guitar this will probably solve it. If not, there may be something physically wrong with your guitar.
If you're having trouble getting the guitar to stay in tune or to sound in tune even when each string is tuned correctly, it's possible that your strings are too old and you need to replace them.
Also, periodically your guitar will expand, contract, or otherwise warp with the change of seasons, necessitating a corrective treatment (a "setup").
Less commonly, other guitar parts will break - saddle, bridge, nut, tuning peg.
If your guitar and your strings are in good shape, the reason from your tuning problem is the classic User Error. Hopefully, in the heat of the moment you will remember to check to make sure that you've got the name of your string right, and then hopefully your life tuning life will be awesome from that point forward.