[Elecraft] I didn't realize what you meant (was RE: WARNING! WARNING! WAR...

[Don Wilhelm]

Al,

AFAIK, you are correct - the large value resistor is primarily there to 
protect the person wearing the wrist strap.

However, I do not like to do any electronic or electrical work on a 
directly grounded and conductive surface - period.  IMHO, there is too 
much of a chance to create a short to ground with an open lead or an 
accidentally placed tool in contact with a conductive work surface.  
Even though we usually do not work on high voltage equipment frequently 
anymore (which is where those practices originated), it is still good 
practice since low voltage power (in particular batteries) can produce a 
lot of damage from high current levels - I have seen several cases of 
molten metal flying around as a result of a shorted low voltage/high 
current source.  Think about it a bit - there is a good (and similar) 
reason for the instruction to ALWAYS remove the grounded lead from an 
automotive battery first (even if it seems non-intuitive at first) - if 
one terminal is left grounded, the tool removing the 'hot' terminal can 
short to the chassis and cause much harm and injury.  Don't think that 
small batteries are harmless either - I once observed a 12 volt pack of 
AA sized NiCAD batteries melt wire and burst when subjected to a direct 
short - it was a destructive test in a controlled lab environment, but 
it convinced me that such things are not harmless.

73,
Don W3FPR

AJSOENKE at aol.com wrote:
>  
> Sorry if I missed something here, and I'm not trying to confuse issues.  But, 
> after 40 years in the industry working with the most sensitive of  
> semiconductor devices, the only requirement for a series resistance that I've  seen used 
> is in the devices like a wrist strap that were attached to the  operators 
> body. The purpose being to protect them from possible contact with  power systems 
> that could place the operator in the HV ground path. The 500K or  larger 
> resistor was usually adequate to provide a non-lethal warning of somethin  amiss. 
>
>