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In Reply to: RE: HFAC safety posted by dave slagle on January 07, 2017 at 08:49:46
"We have all been taught that it takes 100ma across the chest cavity to kill us"
That is NOT an established axiom, nor is it true. The amount of current needed to interfere with and stop the heart is a few mA or less. Because of this, all biomedical equipment in clinics and hospitals uses special low-capacitance transformers to avoid the possiblity of shock. The UL standard for leakage current of Class II devices in the patient care area is 150uA.
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Buy Chinese. Bury freedom.
Follow Ups:
If your doing some live testing, do it with a GFI circuit so you don't feel the effects for more than 40 milliseconds....Never been shocked by more than 60cycles, I might have to ask a couple of my Navy buddies how 400hz feels. One would think the body would react like a capacitor.
Personally, I don't feel anything below 50 volts.
Edits: 01/07/17 01/07/17
I remember the 1/10th of an amp from high school. Google will fight this battle and give you hundreds of different opinions.... In any case the topic I was trying to start a discussion on was if HFAC was more dangerous because of the bodies decreasing impedance with frequency.
dave
"do we need to consider that the voltages in use for filament supplies might be dangerous too?"The supplies I use are isolated from earth ground. There's no current path unless I touch both output leads at the same time. A 30V pk-pk square wave at 66kHz might be uncomfortable or even painful, so I try not to do that. :)
It's also worth mentioning that at some frequency below 1MHz, skin effect begins to take hold. AC current won't travel into the body, but instead flows near the surface. Depending on the frequency, this will create a burn, rather than a shock.
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Buy Chinese. Bury freedom.
Edits: 01/07/17
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