re:rf burns

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mjconway-at-ihug.co.nz>

thanks to everyone who replied to my query about rf burns.

 Doing some google work on some of the suggestions yielded an interesting fact 
which probably explains why we don't feel high frequency voltages. The
quote is 
from Electrical safety and anesthesia by M. Bourke at the University of Ottawa.
It goes "At frequencies of 500,000 Hz, current only flows for about 1 msec,
and 
this current could be buffered by the capacitance behaviour of the cell 
membrane. When the cycle is reversed, the capacitance of the cell is 
discharged. With this process continuing, there is no net change in 
transmembrane potential."

Another quote from a medical physics book "First measurements of the
electrical 
properties of cell membranes were made on red blood cells and it was found
that 
membranes act as capacitors maintaining a potential difference between 
oppositely charged surfaces composed mainly of phospholipids with proteins 
embedded in them. A typical value of the capacitance per unit area is about
1uF 
per square cm for cell membranes."

So I guess what the first quote is saying is that with high frequency currents 
the capacitance of the cell is high enough that it doesn't get charged up much 
by the quickly varying voltage and so the voltage across the cell doesn't 
change much and so we don't feel it.

Best Regards,
Mark