<p>Yes it is in fact pulsing current through the motor. An electric motor is very similar to a speaker, and vibrating the windings at specific frequencies will create different musical tones.</p>
<div class="gmail_quote">On Oct 9, 2011 1:04 PM, "George Kennie" <<a href="mailto:geobet4evr@gmail.com">geobet4evr@gmail.com</a>> wrote:<br type="attribution"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div>I have a question that came up at ther flying field yesterday.</div><div>The query was: What produces the arming tone and the cell count tones that are </div><div>audible when the battery is plugged in to an electric motor powered model?</div>
<div> </div><div>There were guys that were adament that the tones were produced by the current</div><div>surging through the motor.</div><div> </div><div>There was confusion due to the fact that no visible speaker could be observed.</div>
<div> </div><div>I felt that there had to be nano oscillator circuits in the esc working some kind of a</div><div>nano piezo circuit generating the required tones, but I really had no idea.</div><div> </div><div>Can somebody please clear up the confusion, ? anybody,? Peter???</div>
<div> </div><div>Thanks </div><div> </div><div>Georgie </div>
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