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AEC9001 Schottky diode in Z-13/8
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MikeDunlop



Joined: 02 Jan 2012
Posts: 15

PostPosted: Sat May 19, 2012 12:58 pm    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

I'm half way through a new installation of Z-13/8 and have just installed the AEC9001 Schottky diode as per diagram. On testing the installation at this point with NO electrical devices connected I'm getting the following voltage reading from the bus terminals:

DC PWR - Off
E-Bus - Off
Main Bat Bus - 12v
Main Pwr Bus - 0v
E-bus - 0v

DC PWR - On
E-Bus - Off
Main Bat Bus - 12v
Main Pwr Bus - 12v
E-bus - 12v

DC PWR - On
E-Bus - On
Main Bat Bus - 12v
Main Pwr Bus - 12v
E-bus - 12v

DC PWR - Off
E-Bus - On
Main Bat Bus - 12v
Main Pwr Bus - 8v
E-bus - 12v
Question: Why am I getting 8v on Main Pwr Bus on the last test, I would have thought it would have been 0V?

The AEC90001 Schottky Diode is new from AeroElectric and has been installed exactly as per instructions.

MikeD (U.K.)


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PostPosted: Sat May 19, 2012 1:43 pm    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Hi Mike,
It's likely that the Meter you are using has a high Impedance and therefore
you can see a Voltage across the diode
When it's reverse Biased. If the Diode is working correctly it will not let
any current more than few Micro amps flow in the reverse
Direction. Try Using a Using a Diode Checker without applying a voltage to
the Diode. Alternatively Turn the E-Buss on and then
Apply a load to the Main Buss (light Bulb) and see what Voltage you read
then on the Main Buss.

Cheers

John MacCallum
VH-DUU
Rv 10 41016

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PostPosted: Sat May 19, 2012 1:57 pm    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Mike,
The 8V is due to leakage current through the reverse biased Schottky diode.
Let's assume that your voltmeter has an internal resistance of 10 MOhms, which is a fairly high load resistance intended to not affect normal measurements. However, in this case, it is forming a two resistor voltage divider network with the high resistance of the reverse biased diode. Assuming your voltmeter is indeed 10 MOhms, you can determine what the reverse bias resistnace is by doing the math:
1. You know that the voltage across the 10 MOhms of your voltmeter is 8V; therefore, the current through it is E/R = 8/10M = 0.8 uA
2. This current is a series current through both the Schottky diode and the voltmeter
3. Since the diode is dropping 4V, its reverse biased resistance is E/I = 4V/0.8 uA = 5 MOhms
It's as simple as that.  The total resistance is 15 MOhms, and the diode's resistance is 5 MOhms; therefore, it drops 1/3 of the voltage. If you really want to prove what I said, get yourself another meter that has a much higher internal resistance (x10) and see what voltage you measure. It will go toward 12V.
Another way to prove this is to do just the opposite. Put a real world load on the E-bus.  Its relatively low internal resistance will cause most or all of the voltage to appear across the diode; therefore, the E-bus will very close to 0V.
Henador Titzoff

From: MikeDunlop <mdunlop001(at)aol.com>
To: aeroelectric-list(at)matronics.com
Sent: Saturday, May 19, 2012 4:58 PM
Subject: AEC9001 Schottky diode in Z-13/8


--> AeroElectric-List message posted by: "MikeDunlop" <mdunlop001(at)aol.com (mdunlop001(at)aol.com)>

I'm half way through a new installation of Z-13/8 and have just installed the AEC9001 Schottky diode as per diagram. On testing the installation at this point with NO electrical devices connected I'm getting the following voltage reading from the bus terminals:

DC PWR - Off
E-Bus - Off
Main Bat Bus - 12v
Main Pwr Bus - 0v
E-bus - 0v

DC PWR - On
E-Bus - Off
Main Bat Bus - 12v
Main Pwr Bus - 12v
E-bus - 12v

DC PWR  - On
E-Bus - On
Main Bat Bus - 12v
Main Pwr Bus - 12v
E-bus - 12v

DC PWR - Off
E-Bus - On
Main Bat Bus - 12v
Main Pwr Bus - 8v
E-bus - 12v
Question: Why am I getting 8v on Main Pwr Bus on the last test?

The AEC90001 Schottky Diode is new from AeroElectric and has been installed exactly as per instructions.


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MikeDunlop



Joined: 02 Jan 2012
Posts: 15

PostPosted: Sat May 19, 2012 2:19 pm    Post subject: Re: AEC9001 Schottky diode in Z-13/8 Reply with quote

Many thanks for the quick replies. I will check as per your suggestions and also make sure my test equipment and knowledge of electrics are suitable for the job at hand. I'm sure that throughout this installation, both are going to be needed.

MikeD (U.K.)


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JohnInReno



Joined: 08 Sep 2007
Posts: 150

PostPosted: Sat May 19, 2012 2:36 pm    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Your battery should be putting out more than 12 volts. On my
installation, I see about .2 to .3 volt difference between the main
power switch and the alternate feed switch due to the draw of the
contactor. In other words, if you see 12v on the battery bus and 12v on
the power bus then I would suspect your voltmeter is not accurate.

john

On 5/19/2012 1:58 PM, MikeDunlop wrote:
Quote:


I'm half way through a new installation of Z-13/8 and have just installed the AEC9001 Schottky diode as per diagram. On testing the installation at this point with NO electrical devices connected I'm getting the following voltage reading from the bus terminals:

DC PWR - Off
E-Bus - Off
Main Bat Bus - 12v
Main Pwr Bus - 0v
E-bus - 0v

DC PWR - On
E-Bus - Off
Main Bat Bus - 12v
Main Pwr Bus - 12v
E-bus - 12v

DC PWR - On
E-Bus - On
Main Bat Bus - 12v
Main Pwr Bus - 12v
E-bus - 12v

DC PWR - Off
E-Bus - On
Main Bat Bus - 12v
Main Pwr Bus - 8v
E-bus - 12v
Question: Why am I getting 8v on Main Pwr Bus on the last test?

The AEC90001 Schottky Diode is new from AeroElectric and has been installed exactly as per instructions.


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Eric M. Jones



Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

PostPosted: Sun May 20, 2012 5:22 am    Post subject: Re: AEC9001 Schottky diode in Z-13/8 Reply with quote

As others have mentioned, the problem is in how you use your tools...like the voltmeter.

Imagine that you have a voltmeter that is infinitely sensitive (infinite impedance). Now it will measure the battery voltage even thru an open switch. In fact, it will measure 500 volts between your belt buckle and your shoe laces. And the top of your hat will be 1000 volts higher than the soles of your New Balance sneakers. You can actually extract some tiny amount of power this way.

So meter impedance is not a lack of quality in a meter, it is a necessary and useful characteristic of the measuring device. And in a solid state circuit (like a diode), there will almost always be a voltage on the output that is similar to the input voltage even when the circuit is off. And in fact the "leakage voltage" will not be able to light even the tiniest LED...so ignore it.

I once designed a Cmos circuit where somebody (okay, me...) forgot to add the power trace to the IC. Years later, an inquisitive technician, tracing an unrelated fault discovered it, but all the shipped product had worked just fine.

So just don't make voltage measurements like this.

See attached for a better way.


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PostPosted: Sun May 20, 2012 5:51 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Eric,
This sounds like the possible explanation for a problem that I solved but
never understood. Still don't... even if this is the explanation! :>)

20 years ago, I had a sprinkler zone that would not come on. I checked
voltage at the solenoid and found 12V, so I assumed that the solenoid was
bad. I replaced it...still didn't work! I then checked the original
solenoid at the control box. It worked! Hmmmm!

I ran new wires out to the valve from the controller box hooked up the
original solenoid and it worked! Problem solved.

I have never understood how I could have 12V at the solenoid and it would
not work. Is this an explanation and if so how??

Bill B

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Bob McC



Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

PostPosted: Sun May 20, 2012 6:25 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Broken wire, bit of moisture, easily enough to "power" the meter. (Read the
voltage)
No direct connection to actually pass current to power the relatively large
solenoid power requirements.

Bob McC

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Ed Anderson



Joined: 10 Jan 2006
Posts: 475

PostPosted: Sun May 20, 2012 7:16 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Bill,

12Volts at the relay could/did exist - but if you did NOT have an adequate
return path (ground) for CURRENT to flow then no current would flow through
the relay, no power to close the relay would develop and nothing would
happen. You must have a path for current flow. So once you took the relay
back and hooked it up to a good ground - it worked.

Voltage is similar to water pressure - you can have 12PSI of water pressure
on one side of a water valve leading to a water turbine - but if you do not
open the valve (provide a path for water flow) then the 12PSI does nothing
for you, no work is produced and the turbine never spins(relay never
closes).

When I was just getting interested in electronics (around 10 years old), I
would go to the local dump and haul out old discarded radios and cut out the
components. I would take a resistor and measure the resistance with an ohm
meter and sure enough the resistance measure was close(more or less) to the
color code on the resistor - so ah, I thought another good one.

Then I would put voltage (12 volts) to one end of the resistor and then
measure the voltage at the other end and much to my puzzlement and dismay -
no voltage was dropped, it still read 12 volts. So the resistor must have
somehow gone bad - but, measured the resistance again and it was on the
money.

Later the light bulb came on - the impedance of the voltmeter was too high
to draw any significant current through the resistor, therefore there was
only a very small (unnoticable to me) voltage drop across the resistor. Of
course once I grounded one end of the resistor then max current would flow
through it and all 12 volts would be dropped across the resistor. Without
current flow through a resistor (V=I*R) there is no voltage dropped across
it and the voltage will measure the same on both ends of the resistor. In
other words if I (current) = 0 then Voltage Drop V = 0 * R = 0 or no voltage
drop.

Ed
--------------------------------------------------
From: "Bill Bradburry" <bbradburry(at)bellsouth.net>
Sent: Sunday, May 20, 2012 9:50 AM
To: <aeroelectric-list(at)matronics.com>
Subject: RE: Re: AEC9001 Schottky diode in Z-13/8

[quote]
<bbradburry(at)bellsouth.net>

Eric,
This sounds like the possible explanation for a problem that I solved but
never understood. Still don't... even if this is the explanation! :>)

20 years ago, I had a sprinkler zone that would not come on. I checked
voltage at the solenoid and found 12V, so I assumed that the solenoid was
bad. I replaced it...still didn't work! I then checked the original
solenoid at the control box. It worked! Hmmmm!

I ran new wires out to the valve from the controller box hooked up the
original solenoid and it worked! Problem solved.

I have never understood how I could have 12V at the solenoid and it would
not work. Is this an explanation and if so how??

Bill B

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Eric M. Jones



Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

PostPosted: Sun May 20, 2012 7:38 am    Post subject: Re: AEC9001 Schottky diode in Z-13/8 Reply with quote

Bill B.:

Hard to know. But the lesson is that a voltmeter should never, and I mean NEVER be used as a makeshift continuity tester. A 12V indicator lamp is a much better tool.

I used to know an 85-year old electrician nicknamed Sparky (really) who told me that in the early days they never used meters, he would just put his two fingers across the line (even 440V!). But there was a technique to it--one finger on the hot and one on the ground or neutral AT THE SAME INSTANT--And don't touch anything else. Same when removing them. It is easy to do this with 12V, but you have to lick your fingers and press hard. Every kid knows you can test a 9V battery on your tongue and a 1.5V cell can be tested UNDER the tongue.


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PostPosted: Sun May 20, 2012 8:02 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

So you guys now know why, as an electrician, I am a middling carpenter!

Bill B

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PostPosted: Tue May 22, 2012 9:12 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

I really have to ask. Are you making the claim that in all the years
"Sparky" used his fingers, He NEVER had his fingertips touch at
different times? Assuming 60Hz, a difference in contact times of the
the fingertips of 1/30 of a second would allow more than enough time for
any affect that was going to take place between 1st and 2nd finger contact.

Never more than 1/30 of a second, ever.

I'm skeptical.

Raymond Julian
Kettle River, MN

"And you know that I could have me a million more friends,
and all I'd have to lose is my point of view." - John Prine

On 05/20/2012 10:38 AM, Eric M. Jones wrote:
Quote:

Jones"<emjones(at)charter.net>

Bill B.:

Hard to know. But the lesson is that a voltmeter should never, and I
mean NEVER be used as a makeshift continuity tester. A 12V indicator
lamp is a much better tool.

I used to know an 85-year old electrician nicknamed Sparky (really)
who told me that in the early days they never used meters, he would
just put his two fingers across the line (even 440V!). But there was
a technique to it--one finger on the hot and one on the ground or
neutral AT THE SAME INSTANT--And don't touch anything else. Same when
removing them. It is easy to do this with 12V, but you have to lick
your fingers and press hard. Every kid knows you can test a 9V
battery on your tongue and a 1.5V cell can be tested UNDER the
tongue.

-------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive
Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net


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Eric M. Jones



Joined: 10 Jan 2006
Posts: 565
Location: Massachusetts

PostPosted: Tue May 22, 2012 9:30 am    Post subject: Re: Sparky Reply with quote

Quote:
I'm skeptical. Raymond Julian


Raymond. It is important to note that the electrical current flowed only up one finger and down the adjacent finger...never through the body, the heart or any bundle of nerves. So it couldn't kill him.

Sparky also had tough hands that had done hard work for decades....I didn't doubt him at all. There are lots of seemingly-dangerous electrical tricks...if you know what you're doing. At 440V and 25k ohm dry skin, that's only 18 milliamps RMS. It shouldn't be a problem at all.

How about we both try it and report back. YOU FIRST!


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PostPosted: Tue May 22, 2012 10:17 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

I have no doubt he did it. I have done it to 1500v neon lighting
transformers to see it they were hot.

This does not address the "explanation" of how he did it.

Quote:
I used to know an 85-year old electrician nicknamed Sparky (really)
who told me that in the early days they never used meters, he would
just put his two fingers across the line (even 440V!). But there was
a technique to it--one finger on the hot and one on the ground or
neutral AT THE SAME INSTANT--And don't touch anything else. Same when
removing them.

Your claim that there is a technique to it,

-----"AT THE SAME INSTANT"---------

is baseless, based on your explanation below. Which one is it????

Timing of the contact of the fingers has NOTHING to do with it and
retelling stories with no basis in fact serves no purpose except to
perpetuate falsehoods and whatever dangers are associated with believing
them.

Raymond Julian
Kettle River, MN

"And you know that I could have me a million more friends,
and all I'd have to lose is my point of view." - John Prine

On 05/22/2012 12:30 PM, Eric M. Jones wrote:
Quote:

Jones"<emjones(at)charter.net>
> I'm skeptical. Raymond Julian
Raymond. It is important to note that the electrical current flowed
only up one finger and down the adjacent finger...never through the
body, the heart or any bundle of nerves. So it couldn't kill him.

Sparky also had tough hands that had done hard work for decades....I
didn't doubt him at all. There are lots of seemingly-dangerous
electrical tricks...if you know what you're doing. At 440V and 25k
ohm dry skin, that's only 18 milliamps RMS. It shouldn't be a problem
at all.

How about we both try it and report back. YOU FIRST!

-------- Eric M. Jones www.PerihelionDesign.com 113 Brentwood Drive
Southbridge, MA 01550 (508) 764-2072 emjones(at)charter.net


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Eric M. Jones



Joined: 10 Jan 2006
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Location: Massachusetts

PostPosted: Tue May 22, 2012 10:30 am    Post subject: Re: AEC9001 Schottky diode in Z-13/8 Reply with quote

Quote:
Timing of the contact of the fingers has NOTHING to do with it and
retelling stories with no basis in fact serves no purpose except to
perpetuate falsehoods and whatever dangers are associated with believing them.

Raymond Julian


Man, Chill.

That's what he said and I had no reason to disbelieve him. But yes, the two finger thing might not be useful.

Chill!!


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PostPosted: Tue May 22, 2012 10:55 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

This does not address the "explanation" of how he did it.

Quote:
I used to know an 85-year old electrician nicknamed Sparky (really)
who told me that in the early days they never used meters, he would
just put his two fingers across the line (even 440V!). But there was
a technique to it--one finger on the hot and one on the ground or
neutral AT THE SAME INSTANT--And don't touch anything else. Same when
removing them.

Your claim that there is a technique to it,


The part that is not well explained is that you must not be in contact with
any ground. Now you can touch the hot wire and not be shocked, because
there is not a completed circuit through your body. So, If you are not
grounded it makes no difference if you touch both wires at the same time or
not. There is only a completed circuit when you touch both wires, and the
completed circuit is from one finger to the other. Hope this muddies the
waters even more.

Don't do this!! It's a stupid practice!!!

Roger

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PostPosted: Tue May 22, 2012 10:55 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

When I first graduated from high school, I worked construction for one summer with an electrician who used the two finger trick to see if wires were hot.  As long as no other portion of your body was grounded, you wouldn't get hurt.  I spent most of the summer using this technique to see if wires were hot and learned to tell the difference between 110V and 220V feeds.
 
At one point during the summer, I was helping him revive an old elevator from the late 1800s .  At one point he touched two wires to see if they were hot and jerked his hand back in pain.  He dug his multimeter out from the bottom of his toolbox and measure 600V DC on the wires!

jason

  On May 22, 2012 at 1:30 PM "Eric M. Jones" <emjones(at)charter.net> wrote: > --> AeroElectric-List message posted by: "Eric M. Jones" <emjones(at)charter.net> > > > > I'm skeptical.   Raymond Julian > > > Raymond. It is important to note that the electrical current flowed only up one finger and down the adjacent finger...never through the body, the  heart or any bundle of nerves. So it couldn't kill him. > > Sparky also had tough hands that had done hard work for decades....I didn't doubt him at all. There are lots of seemingly-dangerous electrical tricks...if you know what you're doing. At 440V and 25k ohm dry skin, that's only 18 milliamps RMS. It shouldn't be a problem at all. > > How about we both try it and report back. YOU FIRST! > > -------- > Eric M. Jones > www.PerihelionDesign.com > 113 Brentwood Drive > Southbridge, MA 01550 > (508) 764-2072 > emjones(at)charter.net > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=373577#373577 > > > > > > > > > >
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Bob McC



Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

PostPosted: Tue May 22, 2012 10:56 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Eric is correct, can be done under the correct conditions. Not necessarily
good idea, but possible.

I found myself accidentally touching a live 600V 60 Hz wire once. Gets your
attention real quick, but the connection was between a finger and the back
of the same hand which was touching the junction box containing the live
wire, no other ground involved. Very lucky but smarter! (In Canada most 3
phase industrial is 600 not 440 like the US)
I'd turned off, and checked as dead, the main service to the building but
this particular junction box was unfortunately back-fed from another
building's service. I now check the individual circuits every time and not
assume because the building is "dead" that every circuit also is.

Another anecdotal example I personally witnessed was a mechanic, years ago,
who tested the ignition wires on a running V8 auto engine to find a misfire
by unplugging the wire from the spark plug, inserting a screwdriver, which
he then held in his hand while resting against the block. He pronounced
"that ones good" then proceeded to go to the next plug and so on until
finally "there's the bad one". Impressed me no end, but not something I'm
about to try myself.

Do not archive

Bob McC

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raymondj(at)frontiernet.n
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PostPosted: Tue May 22, 2012 11:28 am    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

Chill..... that's your best response.

Nuts.

I was hoping to sort out fact from fiction.

Never mind.

Raymond Julian
Kettle River, MN

"And you know that I could have me a million more friends,
and all I'd have to lose is my point of view." - John Prine

On 05/22/2012 01:30 PM, Eric M. Jones wrote:
Quote:

> Timing of the contact of the fingers has NOTHING to do with it and
> retelling stories with no basis in fact serves no purpose except to
> perpetuate falsehoods and whatever dangers are associated with believing them.
>
> Raymond Julian
Man, Chill.

That's what he said and I had no reason to disbelieve him. But yes, the two finger thing might not be useful.

Chill!!

--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net


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PostPosted: Tue May 22, 2012 1:54 pm    Post subject: AEC9001 Schottky diode in Z-13/8 Reply with quote

I have personally touched ignition wires in a high school electricity class many years ago with supervision from the instructor , after he demonstrated it first. As long as there is no other possible path other than the two fingers all you feel is a strong tingling in the fingers. Dont make a mistake though.

Niko

Nikolaos Napoli

On May 22, 2012, at 2:55 PM, ROGER & JEAN CURTIS <mrspudandcompany(at)verizon.net> wrote:

Quote:



This does not address the "explanation" of how he did it.

> I used to know an 85-year old electrician nicknamed Sparky (really)
> who told me that in the early days they never used meters, he would
> just put his two fingers across the line (even 440V!). But there was
> a technique to it--one finger on the hot and one on the ground or
> neutral AT THE SAME INSTANT--And don't touch anything else. Same when
> removing them.

Your claim that there is a technique to it,




The part that is not well explained is that you must not be in contact with
any ground. Now you can touch the hot wire and not be shocked, because
there is not a completed circuit through your body. So, If you are not
grounded it makes no difference if you touch both wires at the same time or
not. There is only a completed circuit when you touch both wires, and the
completed circuit is from one finger to the other. Hope this muddies the
waters even more.

Don't do this!! It's a stupid practice!!!

Roger

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