More specifically, THIS voltmeter, which is a little bit &quot;under-spec&#x27;ed&quot;, to say the least: Radio Shack (22-223) <a href="https:&#x2F;&#x2F;www.google.de&#x2F;search?q=radio-shack+22-223&amp;tbm=isch" rel="nofollow">https:&#x2F;&#x2F;www.google.de&#x2F;search?q=radio-shack+22-223&amp;tbm=isch</a> It&#x27;s set to the 10V-AC range. I&#x27;d expect a VC backed company to invest in a little more elaborate measurement equipment than that.<p>On the other hand, given a a good RMS meter operated in a frequency range where it&#x27;s spec&#x27;ed to work and a <i>known</i> <i>circuit</i> <i>impedance</i> will give you a very good measurement of the power: P=Vrms²&#x2F;R. And analog meters make for rather pretty demos, to be honest.