How much capacitance does the human body have?

[ExpAnonColin]

It can't vary too much from person-to-person, anyone can play a theremin, no?

-Colin

[Chipper Chapowski]

I have no idea, but wouldn't it be great if you could store up some charge and then zap people at free will.... A bit like rubbing your feet on carpet... Or more like one of the X-men I'd say... Yes......

-Mike

[Boofhead]

Figures of 100pF to 200pF seem to be most common.

Human static discharge is modelled as a 100pF cap in international standards - not much zapping capacity there unless you can get the voltage up.

[Ge_Whiz]

If you calculate the capacitance of the isolated human body, assuming it to be a sphere of 1 metre radius, the answer is about 100 pF. In proximity to the earth, however, it is somewhat higher depending on height above ground, humidity, make of training shoes etc. The capacitance of the entire earth is about 700 uF, which for many years has been taken as effectively "infinite". That puts those 1F mega-capacitors into perspective, doesn't it?

This reminds me of the physicist Sir Arthur Eddington (the guy who realised that we are all made of stuff that was once in stars). He once started a Cambridge University examination question with the words, "Consider a perfectly spherical elephant whose mass may be neglected."

[Mark Hammer]

It will depend on individual skin and atmospheric conditions.  Consider humans as being like "true" capacitors in that they not only have storage properties, but leakage ones as well.  Indeed, the galvanic skin response (GSR) that is measured by polygraphs is a measure of skin conductance.

Having said that, I can't imagine that person-to-person variation is much more than a hundred-fold.

[ExpAnonColin]

So we're thinking from 100-200pf?  Thanks a lot for all the info, guys.

-Colin

[Ansil]

i dont' knwo about capacitance. but i have 2.2 megs resistance :lol:

[Paul Perry (Frostwave)]

If you are in Cambridge Mass, you can measure yourself here:
http://web.mit.edu/Edgerton/www/Capacitance.html

You don't actually touch the theremin to play it, you interfere with the dielectric constant of the field around the antenas. If you accidentally touch the antena, it goes WAY off scale.

[Hal]

about zapping people...its not that hard if you know what you're doing, and you're right, you have to get the voltage up.

Atmospheric conditions don't effect a person's capacatince...but simply how easily they will discharge through the air to ground.

The best way to chage somebody up...as we found...

step one:  rub foam insulation on a sweatshirt.  The foam will get a posative charge, and the shirt a negative.  Place a metal sheet "pie tin" style thing - bent up ends - on the foam, and toutch the end to charge it by induction.  Then lift it up with soemthing insulated and ZAP a person standing next to you.  Repeat about 10 times.  Now send that person to go toutch some unsuspecting person in the ear!

Now, I know this is all static electrisity stuff, but its still fun and it still zaps as for how much charge a person can hold, I have no idea.