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Stange DMM readings

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Gandledorf

New Member
I was working on a circuit tonight, and made the mistake of letting one of my friends use the DMM for me. While it wasn't needed, he decided to measure his "Brain voltage", i.e. touch a probe to each ear... well I'll be darned if it didn't register 20mV. We repeated this test, including assuring ourselves that the DMM was functioning correctly, by measuring a known source. His head continued to show up as 20mV, other objects, a table and a chair, or two points on the same table, registered as 0V...

Very odd if you ask me. Do any of our sages know the answer (Nigel?)?
 

plot

New Member
turn on the ohm meter and you have a resistance too.

you in fact do have a voltage in you (20mV? not sure how much, that seams like a lot though). Your heart produces a small voltage everytime it pumps -- as a matter of fact, that's how EKG's work (you know.. those heart monitors you see on ER and in all the movies that always ends up 'flatlining'), is it measures that voltage everytime your heart pumps.
 

mozikluv

New Member
dmm reading

:D hi gandledorf,

would you also be surprised if the reading would have been 0v ? :lol: :lol: :lol:
 

stevez

Active Member
One of my wife's nursing specialties is cardiac care. One evening I pulled a book from her library on EKGs and was fascinated by the description of the electrical impulses that can be measured at various points on the human body. It cleared up my initial misconception that much of that area was some dark science. The potentials are quite measurable and reveal much about the condition of the cardiovascular system.

What you may have "measured" could have been the voltage resulting from some electro-chemical reaction from the moisture/salts on the skin and the metal probe. It could also have been a good indicator of the real potential that existed.

FYI - I wondered why EKG isn't ECG and what I found was that EKG and ECG is the same thing - the German (I think) word for "cardio" begins with "K".
 

Noggin

Member
i held a geiger (sp) counter by my head and it went nuts, back in high school.
 

B-o-b

New Member
Brain Voltage

I did the same experiment using a Fluke 23 DMM and it read anywhere from 60 to around 100mV! Interesting indeed! Altho, I don't think this is "Brain Voltage" per say, but perhaps some electro-chemical voltage that maybe occurring due to the electrolytes in the skin tissue. I don't deny the fact that there are probably some electrical impulses going on there too, but as to exactly what it is, don't know.

I also did the same experiment by placing the meter probes, 1 in each hand, and I got readings around 20mV or so. Anyway, an Interesting experiment!

Cheerz!

Bob
 

bmcculla

New Member
Your body works like a big antenna picking up all the noise in the room. If you have a scope just touch the probe to yourself to see how big the signals can be. I think these are the signals you're reading. Your "brain voltage" or voltage form your muscles is very small and very high impedance.

All your nerves work with voltage which can be detected with a good circuit. An EMG, which reads the voltage from your muscles is quite easy to make. All you need is an intrumentation amp with good input impedance and a little bit of signal conditioning. Use battery power so you don't accidentaly electrocute yourself.

Brent
 

mozikluv

New Member
electrical impulse from the human body

:D

isn't GOD wonderful, He made us as the first electrical generator! :idea: :lol: :lol:
 

tytower

Banned
I know this is an old post but I could not resist .

I put my probes in moist areas between the you know whats and guess what ..600milliVolts(AC)
Now I got to thinking about this and maybe the body produces some voltages but one thing I do know is any metal lead held in the air is an antenna tuned for some ideal frequency.

I would also assume that the body is capable of absorbing radio waves and I suspect this is most of what is registering. The size of the area would vary which might explain my high measurement.I'm also a ham radio operator and the radio was on at the time although not transmitting -I was otherwise occupied.
 

EN0

Member
According to Nikola Tesla, the brain (and also the ionosphere) is resonant from 6-8Hz. So, maybe that is why we get some electrical impulses near the brain. Tesla also proposed that the brain could be manipulated...scary thought...:eek:
 

tcmtech

Banned
Most Helpful Member
Place the electrodes on different parts of you arm and flex different muscles.
You can change the voltage readings easily and accurately with the right contractions and movements.
Getting consistant and repeatable swings from the relative positive and negative points is not hard to do.
 

Mikebits

Well-Known Member
I put my probes in moist areas between the you know whats

No I do not know what "you know whats", you are referring to, and I think I am afraid to ask.
 
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