I recently purchased a beginner guitar. My first tuning I busted the 3rd string like an idiot. Replaced it with 3rd string that was provided and tuner was showing D. Ordered new strings and replaced with new 3rd string and now tuner is showing A... I'm at a loss. HELP!
Each string needs to be under correct tension in order to be at its correct pitch, or “in tune." They are different thicknesses so that each is optimal for sounding the pitch it’s meant to play, hence strings are named 1, 2, 3, 4, 5, 6 or Low E, A, D, G, B, High E (for standard tuning.)
The pegs on the headstock (small end of guitar) are turned to tighten or loosen tension on the strings, which raises and lowers the pitch of each string, respectively. A new string’s pitch will not be in tune until it has been brought to proper tension. A digital tuner makes finding that pitch easy and they are pretty affordable.
Learn how to tune your guitar from someone who knows how, or go to Youtube and search for one of the many tutorials. I’d suggest you also learn how to change strings properly so that you don’t have unnecessary issues with the guitar staying in tune.
Be diligent about playing in tune. Always check your tuning before you play and often between songs or exercises, especially if it sounds “off.” Changes in temperature and humidity, as well as just the act of playing, can cause any guitar to go out of tune, but especially lower quality instruments that most beginners start with. Also realize that newer strings will continue to stretch and lose their pitch at first, while older strings will be more stable and less prone to this but not sound as lively.
Good luck and have fun!