Measuring body resistance with multimeter

Thread Starter

TsAmE

Joined Apr 19, 2010
72
Using the 2 probes of my multimeter (placing the red probe on my left thumb and black probe on my right thumb) I measured about 1 mega ohm for my body resistance.

Now what I want to know is would this be the resistance of my whole body, or would it be the shortest path the current would take between the 2 terminals (from left hand through chest to right hand)?
 

Wendy

Joined Mar 24, 2008
23,421
Given your sweat problem you probably have extra low resistance. Most people measure very high due to dry skin. Sweat, being basically salt water, is an excellent conductor.
 

Thread Starter

TsAmE

Joined Apr 19, 2010
72
Given your sweat problem you probably have extra low resistance. Most people measure very high due to dry skin. Sweat, being basically salt water, is an excellent conductor.
True. If my hands are dry then I measure around 2 mega ohms.

I also tried using the continuity feature of the multimeter when placing my thumb on each probe and there was no beep. Why is there no beep?
 

debjit625

Joined Apr 17, 2010
790
The continuity feature of the multimeter beeps only when you go down to a very low resistance approx below 100 or less(it depends on the meter check your meter's manual) ,and your skin resistance is very high for that value so it doesnt beeps.
 

beenthere

Joined Apr 20, 2004
15,819
Possibly, but the path of least resistance may include the back or even down to the abdomen. Conduction follows sweat more than a line between points.
 

tom66

Joined May 9, 2009
2,595
There's a Darwin award for some idiot who stuck multimeter probes through their skin and into a vein, and caused fibrilation of their heart. Not sure if it's true, but a multimeter does put a few milliamps across a resistor.
 

Thread Starter

TsAmE

Joined Apr 19, 2010
72
There's a Darwin award for some idiot who stuck multimeter probes through their skin and into a vein, and caused fibrilation of their heart. Not sure if it's true, but a multimeter does put a few milliamps across a resistor.
Yeah I have came across this story before. What confuses me is that how is it possible that one can get current flowing in them (in blood through heart) if they just hold 2 terminals. Wouldnt current flow in someone only in case of sticking the probes into the skin?
 

Paulo540

Joined Nov 23, 2009
191
Yeah I have came across this story before. What confuses me is that how is it possible that one can get current flowing in them (in blood through heart) if they just hold 2 terminals. Wouldnt current flow in someone only in case of sticking the probes into the skin?
Yes, and this is what was done. According to the story, some naval fella either pierced his skin with small needles (or just pushed the probes too hard, i forget) to see what his 'internal resistance' was.

The gold standard for cardiac death is only about 100mA of current. Not too tall of an order for a 9v meter...
 

t06afre

Joined May 11, 2009
5,934
From what I read from that link this is what I think (correct me if I am wrong): if the red probe was on the left thumb and black probe on right thumb, the current would flow from the left hand, along the surface of the skin (past chest surface) to the right hand.
First you should know that skin impedance is very dependent of of parameters like frequency, and current density. The skin impedance will also be much higher then the underlying tissue. We are talking about around 1 K ohm from arm to foot, for the underlying tissue only. So the current would definitely NOT flow in the skin by putting one measurement pin on each thumb. Also The current flow in the human body is due to ion flow, not electrons. In order to do proper measurement on the skin. A transducer that senses ion distribution on the surface of tissue, and converts the ion current to electron current. Is needed for proper measurement. So your kind experimental measurement is not hazardous. As long as you use a battery operated multi-meter. But your approach is pure gobbledygook in any scientific relation.
 

jpanhalt

Joined Jan 18, 2008
11,087
Thank goodness our bodies don't come equipped with tail lights, government microchips (yet), or antipollution devices, or this type of thread would be locked. (sarcasm)

I do think the forum leaders should consider relative risk, including delay in therapy, and legitimate value from such amateur approaches to serious health matters. Just watch the YouTube clip which began the related thread and the rather flippant comment about not plugging the device into a wall socket.

John
 
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