# Hand contact with capacitor negative (excess of electrons) terminal only.

#### Aspenforest

Joined Jan 29, 2013
3

I myself think that the electrons will flow to the
human body and further drain the battery.

#### thatoneguy

Joined Feb 19, 2009
6,359
I myself think that the electrons will flow to the
human body and further drain the battery.
Describe your reasoning in coming to this conclusion.

#### russ_hensel

Joined Jan 11, 2009
825
Why would the body be at a lower potential? And if it is there must be a force.

#### Aspenforest

Joined Jan 29, 2013
3
Describe your reasoning in coming to this conclusion.
I viewed electrons as a fluid. If I push electrons into a capacitor,
they are there under a pressure. Then due to entropy they would
want to naturally flow to a low-pressure area, where there are less electrons.
So the analogy would be a high pressure water container,
from where water would want to escape to the surrounding
medium to balance the pressure difference.

#### thatoneguy

Joined Feb 19, 2009
6,359
Where would current the human body picks up originate from?

#### #12

Joined Nov 30, 2010
18,210
You have to think in terms of a circuit loop. The human must have some capacitive connection to the positive terminal, or there is no potential difference. No voltage = no current. Without a loop, the electrons have no incentive to charge the human to 9 volts.

In the most minute terms, everything is capacitively coupled to everything else, but the capacitance level is microscopic. Therein lies the quantity of capacitance, and therefore, the quantity of electrons that will flow. It's probably unmeasurable. However, you might estimate a pico-pico farad of coupling to the positive terminal and calculate a number of electrons.

#### Aspenforest

Joined Jan 29, 2013
3
But how do you then explain a Van de Graaff generator with a top negative capacitor sphere, which is charged to a high voltage? When you touch that negative sphere capacitor, your hair will stand out, meaning that electrons are transferred to the human body from the negative terminal. Isn't it the same capacitor system, only with high voltage?

#### #12

Joined Nov 30, 2010
18,210
How do I compare a hundred thousand volts to 9 volts? I don't.
The principle is still valid, but at a hundred thousand volts, the air becomes a valid conductor and the soles of your shoes become a significant capacitor with respect to the ground you are standing on.