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I've read that a human plays a theremin by acting as a capacitor, or reducing the capacitance of the theremin.

What properties of a human make it act this way? Is there any way of reducing/negating the effect?

Are there any non-living things that would affect a theremin in the same way?

nb: I've already read this but it doesn't quite address what I'm looking for: How does a Theremin "antenna" work?

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Wilskt
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    *or reducing the capacitance of the theremin* The theremin itself does not have capacitance, it responds to **changes in the capacitance between the antenna and ground**. Humans consist for a large part of salty water. Making humans electrically conducive. Moving parts of this conductor (hands) closer to the antenna changes the capacitance I just mentioned. – Bimpelrekkie Jul 22 '16 at 11:20
  • Do you know how capacitors work? Have you done any research into this subject? – Andy aka Jul 22 '16 at 11:48
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    @FakeMoustache I was about to post the human=bag_of_salty_water answer myself, but I think you should change your comment to an answer. – Neil_UK Jul 22 '16 at 11:48

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The theremin itself does not have capacitance, it responds to changes in the capacitance between the antenna and ground.

Humans consist for a large part of salty water. Making humans electrically conductive. Moving parts of this conductor (your hands) closer to the antenna changes the capacitance I just mentioned and the Theramin responds to these changes.

But there's no wire to ground ??

Correct but usually such a device is powered from the mains which provides it with sort of a connection to "ground". It does not even need to be a real ground connection, a capacitive coupling (any mains supply will have that) is enough to detect the changes near the antenna.

Bimpelrekkie
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  • so if I take a battery, cconvert dc to ac and run a theremin with that, it wouldn't work ? – Vrisk Aug 29 '18 at 08:54
  • @Vrisk it would probably not work or work poorly **unless** you design it to work from a battery. You could use a metal case and connect it to the ground of the circuit (usually the - pole of the battery) . If you use a non-metal case you could cover the inside walls with conductive foil or paint and connect that to the ground of the circuit. – Bimpelrekkie Aug 29 '18 at 09:44