What does an electric tuner's "calibrate" button do?

Question

I have an electric tuner and there's a "calibrate button on it, what does that do?

Answer 1

I assume the Calibrate button changes the pitch reference for the Tuner.

For example the pitch of A is 440 herz . You can change that to any other number so the tuner associates A note with 450 herz for example.

It's useful when for some reason your tuner doesn't associate the right tone with the right frequency. Like if the impedance of the electric circuit changes then the note A which frequency of 440 herz will sound like 430 for the tuner! But if you calibrate the tuner to 430 herz then it will show the right pitch.

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The frequencies for Guitar strings :

E =82.41 Hz

A =110.0 Hz

D =146.8 Hz

G =196.0 Hz

B =246.9 Hz

e = 329.6 Hz

However you don't need to know them to tune your strings. The tuner shows the note that's being played with accordance to the reference pitch. Just make sure the reference pitch is 440 for A.  (note the A for guitar is 110 herz! well thats because it's 2 octaves lower than the reference A. 4*110 =440 ) (82.41*4=329.6)