On Wed, 18 Jan 2006 22:53:53 GMT, james wrote
in :

On Mon, 16 Jan 2006 13:31:56 GMT, Lancer wrote:

+ Maybe you should read Ansi standard ANSI/ESD-S20-1999. It states
+Soldering Irons should have a tip to ground resistance of less than 1
+ohm. Companies spends tons of money each year to prevent static
+damge, and that icludes insuring that everything is at the same
+potential. Including the operator and all equipment he uses. Thats
+why iron's that are ANSI rated have a third wire, the ground. It
+wasn't put there to prevent the user from being "shocked"
******

maybe you should study Coulomb's and Guass' Law and understand how
Static Charges are developed. A soldering iron sitting on a
anti-static mat plugged into the wall is not going to develope large
electrostatic charge.


"Large" is a relative term.


What does happen is the tip of a soldering iron is in the strong field
of a time varying magnetic field. This comes from the inductance in
the heater coil. Putting the tip at ground potential will eliminate
any potential charge build up from the time varying magnetic field
from teh heater coil.


What you are ignoring is that the electromagnetic field from AC
current doesn't create -any- potential charge on the tip. The net
charge is zero, and any instantaneous potential charge is the result
of eddy currents which are almost non-existent. More specifically.....

If the tip is the secondary winding of a transformer as you suggest,
the effective number of turns on that winding is 1 turn, while the
primary (the heater coil) has considerably more than 1 turn. So any
voltage developed as a result of electromagnetic induction is going to
be low from the get-go. But that voltage is actually lower because the
tip is really just a shorted loop and is made with a material that has
a very low resistance. Not to mention that the number of primary turns
isn't going to be optimum for power transfer, nor does it have a
ferro-magnetic core. It's a ****-poor transformer at best.

Your theory is further flawed because it assumes an unshielded heater
using wire that is wound into a solenoid -- an assumption that, like
most assumptions, is frequently wrong. Almost all AC soldering irons
these days have shielded heaters, and many heaters are wound to be
non-inductive; i.e, they can't induce a current in squat, let alone
develop any significant (measurable) voltage on the tip. Then you have
the problem that the irons used for chips are only 15-30 watts, and
virtually all of those watts are converted to heat (after all, that's
the intended purpose of the soldering iron, isn't it?).

So here's your theory so far: A tiny fraction of 30 watts (I'm being
generous here) is converted to an electromagnetic field, worms its way
past the heater's shield where it loses most of its energy to eddy
currents, induces a current in a shorted, 1-turn secondary with very
low resistance and develops enough voltage to cause damage to.....
your imagination.


Go back to school.








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