From: payner@netcom.com (Rich Payne)
Subject: Re: Exam mode in version J (var lock?)
Organization: Netcom - Online Communication Services (408 241-9760 guest)
Date: Sat, 23 Jan 1993 03:05:45 GMT

In article <1993Jan19.164320.14325@doug.cae.wisc.edu> kolstad@cae.wisc.edu (Joel Kolstad) writes:
>In article <1993Jan19.193729.6825@netcom.com> payner@netcom.com (Rich Payne) writes:
>>In article <1993Jan16.125606.1940@doug.cae.wisc.edu> kolstad@cae.wisc.edu (Joel Kolstad) writes:
>>>In article <4sDgXB5w165w@kf8nh.wariat.org> kf8nh@kf8nh.wariat.org (Brandon S. Allbery) writes:
>>>>
>>>>But a lightning strike kills you from voltage, not RF.  
>>>
>>>Actually, current fries you, regardless of whether it's lightning or RF.
>>
>>Current is always the -dependant- variable, it is a result, not a cause. 
>
>Current isn't a cause of frying you?  Current is a _result_ of frying you?
>I think not. :-)  Just kidding... I know you mean that current is the
>result of lightning.

Lets say that current is a result of the applied voltage, lightening in
this case. Very high voltage = very high current. 
 
>It's kind of relative, though... after all, we're all going to die
>indirectly because we were born.  

Which must have something to do with the topic...

>                                   At the other extreme, you can get very
>very technical about exactly what killed you.  But usually one talks about
>the _most_ direct cause of death, which I think is the current.  I'll buy
>your argument that it's the lightning itself I guess...

This was not what I said, and it is not especially meaningful to me. But
on the brighter side, it seems to be true, in a non-specific sort of way.
 
>>Generally, the resulting current will increase more of less linearly
>>with the applied voltage.
>
>Although humans are as complex impedences, so frequency matters
>too.  

Do you expect lightening to be of such high frequency that the skin
effect need be considered? What exactly are we talking about?

>60Hz (e.g., from the wall socket) is apparently just about the best
>frequency to choose if you're trying to stop someone's heart. :-)  

Well gee, that is about the normal heart rate. But I would not feel
especially safe working around 400 cycle equipment either...

>                                                                   Tesla
>coils produce such a high frequency current that it literally flows over
>the outer surface of your skin, penetrating hardly at all, so it'll never
>get anywhere near your heart.

You know, there is a general rule that if anything is gonna be accomplished
in a discussion, both parties must be talking about the same thing. If you
really think about it, it makes sense. 
 
>> For safety sake, avoid high voltages, and
>>pay no attention to current arguments, which might be misleading to those
>>who have never worked with electricity. 
>
>Yes, good advice.  Although it's hard to avoid that 10KV potential on the
>door knob when you've been rubbing your feet across the carpet, sometimes.
>:-)  (Especially in the dry frozen tundra of Wisconsin here!)

Then wear a ground strap for safety. :^}  Heres a case where we have high
voltage, electrons scattered mostly about the skin, and 0 HZ. The charge
is static. Curiously, this is related to lightening, but not to DC and AC
voltage sources.
 
>>Radar -is- a microwave. 
>
>I meant microwave in the sense of "those things we cook hot dogs in."  

Said microwaves being indistinguishable from the ones used by radar sets.
You have made a distinction where there is no difference.

>                                                                     They
>use a different frequency than radar dishes, though you're quite right that
>both are technically microwaves.  (Microwave ovens are tuned to create the
>greatest loss tangent in water.)

Really, then why do fats heat so much faster?
 
>>The hypothetical "exam-mode transmitter" might be plugged into a grounded
>>wall socket.
>
>Hey, I designed the exam-mode transmitter, and I'm telling you that it's
>battery powered!   (This was to prevent devious EE's from disconnecting the
>outlet immediately prior to the exam. :-) )

Ok, what frequency does it operate at? Wonder where I can dig up a spectrum
analyzer? Then again, the HP would be the obvious place to check.
 
>					---Joel Kolstad


Rich

payner@netcom.com


Newsgroups: comp.sys.hp48