Kev, I think you have this reversed (others will correct me if I'm wrong). Edison pushed for DC because AC causes muscles to contract and continue to contract (multiple pulses) where as DC will cause only one contraction and then the muscle will relax (but may still fry!) as it adjusts to the new constant current flow. A heart will continue to beat with DC applied after an initial interruption, but the same voltage and max current of AC will cause it to stop. 60Hz AC does not allow your grip to release because it is A) way to fast and B) the negative cycle does not activate the opposing muscle that is required to open the hand; it re-activates the same muscle so the only time it is not stimulated is at the zero crossing. Edison also wanted to put power generation into the hands of the people, or at least the local government, rather then in the hands of the "power baron's" and DC would have required many local generation stations rather than one central system due to transmission losses inherent in DC. The advantages of each system are debatable with many good points on each side. But IMHO, AC is far, far more dangerous. James Newton, webmaster http://get.to/techref (hint: you can add your own private info to the techref) mailto:jamesnewton@geocities.com 1-619-652-0593 phone -----Original Message----- From: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Kevin Allenzovic Sent: Thursday, September 09, 1999 10:02 PM To: PICLIST@MITVMA.MIT.EDU Subject: Re: cats! -Reply This sounds a little impossible as AC would alternately contract and release your muscles forcing you to release it! This is one of the reasons we have AC supplied to our home and not DC, among ather obvious reasons. Edison pushed for the use of AC by demonstrating on a horse. He'd fist hit it with AC and watch it bolt. When caught he'd again shcok it with DC killing it stone dead. >>> Peter van Hoof 10/September/1999 12:16pm >>> This depends very much on circumstances sometimes defying logic or explanation as a teenager I grabbed the two poles of a 3kg heavy neon transformer...7kv @100ma... you would assume since current flowed from hand to hand, path over the chest this should be deadly..... it was not. I did not manage to release the poles but after about 15 seconds managed to kick the plug out of the outlet. I survived , shaken , but unharmed. Peter van Hoof ------------- mailto:pvh@vertonet.com http://go.to/pvh [snip] > more than is necessary to kill a cat,or a human for that matter. Also, I > hope the term "slight shock" in reference to 150mA is sarchastic,because > that is also more than a lethal level of current. > > For a person, IIRC, 1 or 2 mA is considered maximum safe level > (and this is > only from a medical standpoint, it is NOT considered safe to allow that > much to flow thru a person on purpose). By touching the case of an old > scope, I found out that I can actually slightly feel only a few 100uA (the > transformer-to-case isolation must have been less than it should > be,another > strong argument for isolation transformers!) Something like 4mA is pain > threshold, 20mA strong muscle contractions, 50mA heart rhythm disruption, > 100mA death likely. This also depends on the path the current > takes. I find > it AMAZING that defibrilators are designed to push something like 10A thru > a person! I wouldn't have thought it possible to do so without REALLY high > voltages and large burns. > > In short,I hope you didn't really do this because a little kid could > probably get killed by something like this. .