electrical shock
Pao said:
Hi
You know these devices EMNS that claim to stimulate the muscle. a person usually has skin resistance of 1000 ohms in wet skin, to 500,000 ohms in dry skin and usually 20mA is already enough to kill or injure a person, so i was thinkin (1Kohms)(20mA) = 20V or .5M(20mA) = 10kV
Ive seen one ad that says that a 9V supplied device can stimulate a person. Is that even possible? How would the the circuit look? it would have a stepup transformer at its output side that probably would not be just a 9V? I was looking for a circuit for these devices on the net but failed find any.
Pao
a heart pacer uses an electrical signal of just a few volts.
That is possible because the heart muscles and the activating nerves
practically touch each other, so the chemical ionic exchange between the muscle and nerve can be activated by a 70 mv from the nerve.
applying a 9v battery internally to that nerve contact would cause a heart attack.
Applying the same 9 volt to the exterior of the human body would produce, perhaps, a 1 millivolt on the heart muscle :
because of the tremendous voltage division caused by many series-parallel electrical resistance paths between the skin and the heart.
When a high voltage is connected to the skin things change. Even dry human skin has sweat pores etc.
the body flesh has salts and liquid blood.
that results in extremely non linear body resistance.
9v across the hands might cause 1mv to reach the heart
220v could cause 100 mv to reach the heart.
Look out ! that's dangerous.
The numbers are just my guess-estimate.
hawk2eye