Simply play a note on your instrument, let Tuner detect the pitch and see where you are on the scale. If the needle points to the left your pitch is lower than the standard pitch, if it points to the right it is higher. In upright position you are in tune.
Tunes your guitar, bass or other musical instrument that can sustain a tone, except pianos, which are tuned slightly stretched (tempered tuning).
Keywords: guitar, tuner, tune, stimmgerät, gitarrenstimmgerät, gitarre, stimmen