On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by
sticking his fingers in light sockets where he perceives a "slight
tingle." I personally can't feel 60V dc *at all* and would be
interested to know of others experiences of the lowest voltage they
can feel - without suggesting anyone do so, of course. Based on past
experience, I suppose.

--

"I believe history will be kind to me, since I intend
to write it." - Winston Churchill

On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote:

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by

It also matters what the surface resistance of your skin is, and how
good a "connection" to the nervous system and heart.

For example, You could put dry fingers on a 9V battery and not feel a
thing, but if you lick your fingers first, get a real tingle. Same
voltage, but the moisture allows current to flow.

In medicine, the defibrillator paddles are covered with a conductive
gel, and use a precise pulse of voltage and current. In open heart
procedures, lower voltage and current is used, with paddles applied
directly to the heart.

Of course, disrupting the heart rhythm may happen with lower voltage,
especially AC or RF.

Why is being careful such a problem for some?

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

In article , Gary S.
Idontwantspam@net writes:

On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote:

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by

It also matters what the surface resistance of your skin is, and how
good a "connection" to the nervous system and heart.

For example, You could put dry fingers on a 9V battery and not feel a
thing, but if you lick your fingers first, get a real tingle. Same
voltage, but the moisture allows current to flow.

Too bad the old "B" batteries aren't common any more. As a 15 year
old (back in the prehistory of mankind) newcomer hobbyist to radio
and electronics, I couldn't feel anything across the snap-on terminals
of a 67 V "B" battery. Curious, I touched my tongue to them.

Z A P ! ! ! !

Stunned, I waited about a half hour to get my tongue unrolled.

Never EVER tried such a totally dumb idea again...

In medicine, the defibrillator paddles are covered with a conductive
gel, and use a precise pulse of voltage and current. In open heart
procedures, lower voltage and current is used, with paddles applied
directly to the heart.

True enough. What is overlooked is that medical instruments,
meters, appliances are all precisely calibrated-adjusted-designed-
to-be-stable-in-their-settings...based on KNOWN INFORMATION to
medical and biological people.

Of course, disrupting the heart rhythm may happen with lower voltage,
especially AC or RF.

Why is being careful such a problem for some?

Bravado and a general feeling of immortality. Especially true for males
and once useful as a survival thing way back in time.

Some actually believe their boast "It can't happen to ME!" :-(

No problem for the morticians...keeps their business going.

The solid-state era was born with a dangerous side-effect: Low supply
voltages. High voltages of 100 to 300 VDC weren't needed with
transistors. Most folks are not able to feel supply voltages under 15
V, DC or AC. As a result they get way too CASUAL about handling
supply rails with the power on. "Familiarity breeds contempt," etc.

When they take that casual attitude towards handling mains supplies
with 115 to 230 VAC input, there's trouble just waiting to happen. It's
like sticking one's hand into a snake basket...the snake may bite or it
may not, depends on the snake...if it bites the bite can be deadly.

Len Anderson
retired and still living in the current reality after 56 years in electric
things

In article , Gary S.
Idontwantspam@net writes:

On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote:

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by

It also matters what the surface resistance of your skin is, and how
good a "connection" to the nervous system and heart.

For example, You could put dry fingers on a 9V battery and not feel a
thing, but if you lick your fingers first, get a real tingle. Same
voltage, but the moisture allows current to flow.

Too bad the old "B" batteries aren't common any more. As a 15 year
old (back in the prehistory of mankind) newcomer hobbyist to radio
and electronics, I couldn't feel anything across the snap-on terminals
of a 67 V "B" battery. Curious, I touched my tongue to them.

Z A P ! ! ! !

Stunned, I waited about a half hour to get my tongue unrolled.

Never EVER tried such a totally dumb idea again...

In medicine, the defibrillator paddles are covered with a conductive
gel, and use a precise pulse of voltage and current. In open heart
procedures, lower voltage and current is used, with paddles applied
directly to the heart.

True enough. What is overlooked is that medical instruments,
meters, appliances are all precisely calibrated-adjusted-designed-
to-be-stable-in-their-settings...based on KNOWN INFORMATION to
medical and biological people.

Of course, disrupting the heart rhythm may happen with lower voltage,
especially AC or RF.

Why is being careful such a problem for some?

Bravado and a general feeling of immortality. Especially true for males
and once useful as a survival thing way back in time.

Some actually believe their boast "It can't happen to ME!" :-(

No problem for the morticians...keeps their business going.

The solid-state era was born with a dangerous side-effect: Low supply
voltages. High voltages of 100 to 300 VDC weren't needed with
transistors. Most folks are not able to feel supply voltages under 15
V, DC or AC. As a result they get way too CASUAL about handling
supply rails with the power on. "Familiarity breeds contempt," etc.

When they take that casual attitude towards handling mains supplies
with 115 to 230 VAC input, there's trouble just waiting to happen. It's
like sticking one's hand into a snake basket...the snake may bite or it
may not, depends on the snake...if it bites the bite can be deadly.

Len Anderson
retired and still living in the current reality after 56 years in electric
things

On Sun, 10 Aug 2003 13:06:23 +0100, Paul Burridge
wrote:

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by

It also matters what the surface resistance of your skin is, and how
good a "connection" to the nervous system and heart.

For example, You could put dry fingers on a 9V battery and not feel a
thing, but if you lick your fingers first, get a real tingle. Same
voltage, but the moisture allows current to flow.

In medicine, the defibrillator paddles are covered with a conductive
gel, and use a precise pulse of voltage and current. In open heart
procedures, lower voltage and current is used, with paddles applied
directly to the heart.

Of course, disrupting the heart rhythm may happen with lower voltage,
especially AC or RF.

Why is being careful such a problem for some?

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

On 10 Aug 2003 03:22:06 GMT, (Avery Fineman)
wrote:

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

As a general safety rule I'm sure you're right. However it does
overlook the fact that different individuals have different tolerance
levels, hence the fatality at 12V (the only recorded one, I believe)
and that Polish electrician who checks for the presence of 230VAC by
sticking his fingers in light sockets where he perceives a "slight
tingle." I personally can't feel 60V dc *at all* and would be
interested to know of others experiences of the lowest voltage they
can feel - without suggesting anyone do so, of course. Based on past
experience, I suppose.

--

"I believe history will be kind to me, since I intend
to write it." - Winston Churchill

In article , Paul Burridge
writes:

On 09 Aug 2003 19:46:02 GMT, (Avery Fineman)
wrote:

If the source has over 30 Volts and can supply over 30 milliamperes
through the cardiac region, you will go into cardiac fibrilation.

Sorry, Len, but I can't see it. I routinely check for HV on the anodes
of certain smallish valves with bare fingers and can't even begin to
feel anything under about 80 volts (at very much more current
capability than 30mA) at the low end. However, I read somewhere that
some guy died from just a 12V 'shock' - must have been a world
record.. :-(

I'm not concerned with what YOU do personally, nor will I set any
"standards" for all humans based on what one human can or can't
do or feel.

I got the "30-30" phrase while working at Birtcher Instruments, a
semiconductor test instrument maker and a division of Birtcher
Medical that made several different medical electronic instruments
(EKG, RF knife/cautery, defibrilators,etc.). Someone at Birtcher
Medical told me about it. I was Chief Engineer at Birtcher Instruments
in Monterey Park, California, a suburb of Los Angeles (not the upstate
Monterey, CA, where some FedEx deliveries went, hi). I don't think
that my employer at the time would give me false information.

The City of Los Angeles building and safety codes don't require
inspection of 24 VAC wiring in residences and that sort of wiring is
common here for furnace and HVAC controls, doorbells, etc. That
AC voltage is never considered "high voltage." That is probably true
of the USA National Electrical Code although I haven't read one
recently (I've only read the coding in the Numeric Electromagnetic
Code recently, quite different from the other "NEC").

I really don't know the medical-biological low threashold for direct
cardiac stimulation through an opening in the chest cavity. I don't
care to know. I care to know NOT to futz around with my or anyone
else's body with anything above the "30-30" limits.

If YOU want to experiment with your own body, feel free. Then you
transport yourself to that other "reality." When you get there, ask
someone there to shock themselves into this reality and tell us all what
it is like "over there." I live in THIS reality where survival depends on
not treating electricity cavalierly like it was words in a newsgroup.

Happy zapping.

Len Anderson
retired (from regular hours) electronic engineer person

In article , "Mike Gilmour"
writes:

Maybe apocryphal but I heard that if you're stupid enough to look into an
open waveguide of an active 10cm marine radar it would cause that eye to
become the equivalent of a hard boiled egg. No need for a 3 minute timer
then?

Back when I was doing electronic instrumentation with an optics group
at Rockwell, my first day in that group brought forth a caution from one
of the optical physicists about lasers: "Do NOT look INTO a laser beam
unless you want that to be the LAST thing you see."

That was with a little 10 milliWatt laser used on their optical table
for initial system calibration.

Good advice I thought...and remembered it.

I'm sure there are some in here who want to gabble about "open wave-
guide" and it "not radiating much because it is open, represents a
discontinuity, and the VSWR is so high there won't be any power
radiated." Which MIGHT happen at any microwave frequency from
L-band bottom (1 GHz) on up past Ku band (24 GHz+). That will
depend on the wavelength of the physical waveguide opening to the
microwave source. The magnetron MAY also refuse to oscillate due
to a high VSWR, flash over and trip its breaker or something to not
operate. Then again it MAY - with equal likelyhood - work just fine
with an opening and radiate FULL power out that open waveguide.
Or something in between full power and no power...a big unknown.

No matter how much anyone likes hardboiled eggs, those belong in
the mouth and not the eye sockets.

Len Anderson
still looking at the world of electric things with cautious eyes

On 10 Aug 2003 19:51:26 GMT, (Avery Fineman)
wrote:

Back when I was doing electronic instrumentation with an optics group
at Rockwell, my first day in that group brought forth a caution from one
of the optical physicists about lasers: "Do NOT look INTO a laser beam
unless you want that to be the LAST thing you see."

One I've seen:

"Do not look into Laser beam with remaining eye."

Happy trails,
Gary (net.yogi.bear)
------------------------------------------------
at the 51st percentile of ursine intelligence

Gary D. Schwartz, Needham, MA, USA
Please reply to: garyDOTschwartzATpoboxDOTcom

Avery Fineman wrote:

In article , "Mike Gilmour"
writes:

Maybe apocryphal but I heard that if you're stupid enough to look into an
open waveguide of an active 10cm marine radar it would cause that eye to
become the equivalent of a hard boiled egg. No need for a 3 minute timer
then?

Back when I was doing electronic instrumentation with an optics group
at Rockwell, my first day in that group brought forth a caution from one
of the optical physicists about lasers: "Do NOT look INTO a laser beam
unless you want that to be the LAST thing you see."

That was with a little 10 milliWatt laser used on their optical table
for initial system calibration.

Good advice I thought...and remembered it.

I'm sure there are some in here who want to gabble about "open wave-
guide" and it "not radiating much because it is open, represents a
discontinuity, and the VSWR is so high there won't be any power
radiated." Which MIGHT happen at any microwave frequency from
L-band bottom (1 GHz) on up past Ku band (24 GHz+). That will
depend on the wavelength of the physical waveguide opening to the
microwave source. The magnetron MAY also refuse to oscillate due
to a high VSWR, flash over and trip its breaker or something to not
operate. Then again it MAY - with equal likelyhood - work just fine
with an opening and radiate FULL power out that open waveguide.
Or something in between full power and no power...a big unknown.

No matter how much anyone likes hardboiled eggs, those belong in
the mouth and not the eye sockets.

I like this sign:

"Do not look into the laser with your remaining eye ..."

Rob