What is the internal Ac impedance of the human body?
ScottH, Sun Mar 26 2017, 06:46PMI know Ac and DC travel through the body differently, and websites state the internal body's resistance arm to arm to be anywhere from 80-1k Ohms. I have also read that high voltage breakdown drops a 1k Ohm resistance in the body to 500 Ohms.
I'm thinking that all of those values are for DC resistance. I know different people have different resistance values.
Would those resistance values change very much if the current was 60Hz Ac. What would the average internal (no skin resistance) impedance be on a 200lb man arm to arm? If there isn't a set answer, what would a typical range look like?
Re: What is the internal Ac impedance of the human body?
GrantX, Mon Mar 27 2017, 06:09AM
Its hard to come up with a set answer, like you say. 60Hz is a very low frequency, so I suspect there wouldn't be a noticeable difference in the range of values compared to DC. For example, the inductance of a 2 metre wire with a diameter of 6mm (ignoring human bodies at the moment) is approximately 2.5uH, which has an impedance of only 942 micro-Ohms at 60Hz. So the DC resistance of the wire is the dominant parameter by a huge margin. The same wire has an impedance of 942 Ohms at 60MHz, which is deep into RF territory.
GrantX, Mon Mar 27 2017, 06:09AM
Its hard to come up with a set answer, like you say. 60Hz is a very low frequency, so I suspect there wouldn't be a noticeable difference in the range of values compared to DC. For example, the inductance of a 2 metre wire with a diameter of 6mm (ignoring human bodies at the moment) is approximately 2.5uH, which has an impedance of only 942 micro-Ohms at 60Hz. So the DC resistance of the wire is the dominant parameter by a huge margin. The same wire has an impedance of 942 Ohms at 60MHz, which is deep into RF territory.
Re: What is the internal Ac impedance of the human body?
Sulaiman, Mon Mar 27 2017, 07:06AM
ScottH
before you probe yourself, read this
............................................
Gra ntX,
a 2m length of wire is approximately 0.4 wavelengths at 60 MHz
so X = 2.pi.f.L will not give a meaningful answer
Sulaiman, Mon Mar 27 2017, 07:06AM
ScottH
before you probe yourself, read this
............................................
Gra ntX,
a 2m length of wire is approximately 0.4 wavelengths at 60 MHz
so X = 2.pi.f.L will not give a meaningful answer
Re: What is the internal Ac impedance of the human body?
GrantX, Tue Mar 28 2017, 03:17AM
Ahh, thanks for the correction. I'd over-simplified the situation for the sake of the example, so my previous post is a bit misleading.
GrantX, Tue Mar 28 2017, 03:17AM
Ahh, thanks for the correction. I'd over-simplified the situation for the sake of the example, so my previous post is a bit misleading.
Re: What is the internal Ac impedance of the human body?
radiotech, Fri Apr 07 2017, 06:57AM
You would really need to consult with a pro tem occupant of the Chair of
Applied Electricity in the past. That would lead to a institutional final answer .
radiotech, Fri Apr 07 2017, 06:57AM
You would really need to consult with a pro tem occupant of the Chair of
Applied Electricity in the past. That would lead to a institutional final answer .
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