MessageView 421F schematic

[TokaMundo]

On Fri, 01 Jul 2005 22:44:07 GMT, "Blarg" <blarg@threadender.net> Gave
us:

I've worked in a Faraday cage, so I know what you're saying is true.
But what I can't figure out is why the elevator at work, which has four
stainless steel walls, fails to stop my cell phone from working. Works
great, other than the elevator ride is too short. ;-)

If you "know" what was going on in the first sentence, then why do
you contradict it in the second.

Four metallic walls does NOT a faraday cage make. It can't even
shield low frequency RF, much less GHz RF.

 

[Marvin]

WAYNEL wrote:

I've conducted a simple experiment on a glass sample that has two clean
copper electrodes biased with 20v DC. Between the two electrodes I
have placed a drop of de-ionised water with Universal Indicator added.

Over a period of time the electrodes changes colour, as expected, with
the cathode going purple (OH-) and the anode going red (H+).

After a longer period of time the colours start to spread out toward
the opposing electrodes, pH gradient. However, the amount the purple
(OH-)spreads is apx three times greater that that of the red (H+).

I have repeated this 10 times in random positions and I get the same
results.

I would have thought that the H+ ions would have more mobility than the
OH- ions and thus I would have expected the opposite to happen.

Can anyone help and through some light on this phenomena, or have I
missed something?


Cheers

WayneL

You shouldn't interpret the data in terms of H+ OH- concentrations without taking into

account how the color of the indicator changes with changes in each of those ions. And
that is a nearly impossible task without quantitative measurements.

Regarding mobilities, keep in mind that electrical neutrality must be present even
loaccly. If H+ is moving, something else must also move to maintain local electrical
neutrality.

 

[Aubrey McIntosh, Ph.D.]

WAYNEL wrote:

I would have thought that the H+ ions would have more mobility than the
OH- ions and thus I would have expected the opposite to happen.

Can anyone help and through some light on this phenomena, or have I
missed something?

The indicator surely has a neutral and an ionized form. The neutral
form diffuses at one rate. The ionized form diffuses faster under the
influence of the electric field.

To test this, take some acid function ( -COOH ) and some amine function
(-NH2 ) indicators and see if they behave in opposite ways.

I'm away from my references or I'd give some examples.

 

[Mike Monett]

Wayne wrote:

I've conducted a simple experiment on a glass sample that has two
clean copper electrodes biased with 20v DC. Between the two
electrodes I have placed a drop of de-ionised water with Universal
Indicator added.

Over a period of time the electrodes changes colour, as expected,
with the cathode going purple (OH-) and the anode going red (H+).

After a longer period of time the colours start to spread out
toward the opposing electrodes, pH gradient. However, the amount
the purple (OH-) spreads is apx three times greater that that of
the red (H+).

I have repeated this 10 times in random positions and I get the
same results.

I would have thought that the H+ ions would have more mobility
than the OH- ions and thus I would have expected the opposite to
happen.

Can anyone help and through some light on this phenomena, or have
I missed something?

Cheers

WayneL

Hi Wayne,

Raw hydrogen ions cannot exist naked in solution. They combine with
a nearby hydroxyl molecule to form H3O. You are actually generating
copper ions at the anode, not hydrogen ions. The process is

1. At the anode, a copper atom gives up two electrons to become an
ion:

Cu(s) - 2e --> Cu(++)

2. At the cathode, water dissociates and hydrogen ions accept
electrons to form hydrogen gas which escapes:

2H2O --> 2H(+) + 2OH(-)

2H(+) + 2e --> H2(g)

So for every copper ion, two hydroxyl ions are produced.

This is why telephone circuits use negative polarity. If the voltage
was positive, small leakage currents would cause the wire to
disappear through electrolysis.

You can calculate the amount of copper ions in solution by knowing
the current and the time interval. The calculations are highly prone
to error due to the numerous unit conversions needed, but a dos
program written by Roger Schafley called Mercury will do the
conversions for you. Here is an example calculation I use for a much
larger electrolysis cell:

--------------------------------------------------------------------

; Colloidal Copper Generator
; Calculations Bob Lee's method
; Note change
; k = 0.5* 63.5 / 96485 ; Coulombs required per gram of copper

; Roger Schafly's Mercury is available at
; http://www.mindspring.com/~schlafly/eureka.htm
; http://archives.math.utk.edu/software/msdos/calculus/mrcry209/.html
; http://archives.math.utk.edu/software/msdos/calculus/mrcry209/mrcry209.zip

Cou = I * sec ; total number of Coulombs
esec = I / 1.60217733e-19; electrons per second
gm = k * I * sec ; Faraday's equation
isin = esec / sqin ; ions per sq. in. per sec
isnm = isin / 6.45e14 ; ions per square nanometer per sec
k = 0.5* 63.5 / 96485 ; Coulombs required per gram of copper
lt = 3.785 * gal ; convert gallons to litres
lt = ml / 1000 ; convert millilitres to litres
mg = gm * 1000 ; convert grams to milligrams
ml = 29.57 * oz ; convert ounce to milliliters
phr = ppm / hrs ; ppm per hour
ppm = mg / lt ; 1 ppm is 1 milligram per litre
sec = hrs * 3600 + mnt * 60 ; convert hours to seconds
uAin = 1e6 * I / sqin ; current density in uA per sq in

hrs = 1
I = 3.111e-3 ; current 02 3.3k 3.111 mA
ml = 1450 ; volume of dw
mnt = 0 ; minutes
sqin = 9.5 ; wetted area

--------------------------------------------------------------------

Here is the solution:

--------------------------------------------------------------------

Cou = 11.1996
gal = 0.38309
gm = 0.00368
hrs = 1.00000
I = 0.00311
k = 0.00032
lt = 1.45000
mg = 3.68541
ml = 1450.00
mnt = 0.00000
oz = 49.0361
phr = 2.54166
ppm = 2.54166
sec = 3600.00
sqin = 9.50000
uAin = 327.473

--------------------------------------------------------------------

In this example, 0.00368 grams of copper were released giving a
concentration of 2.54166 ppm (parts per million). It turns out the
maximum you can achieve is about 3ppm before the copper starts
plating out on the cathode.

As far as the change in color, I posted the results of two
experiments using silver ions that show how to make these ions
visible:

CS> Making Ions Visible
http://escribe.com/health/thesilverlist/m61491.html

Re: CS> Making Ions Visible
http://escribe.com/health/thesilverlist/m61527.html

In my example, the silver ions seemed to have the same mobility as
the hydroxyl ions, since the color bands appeared to meet in the
middle in the first experiment.

Since the mobility is a function of the size of the ion and the
applied voltage, I would expect the copper to move much slower than
the hydroxyl. This appears to be the reverse of what you observe.

Perhaps someone at sci.chem can offer an explanation.

Mike Monett

 

[Mike Monett]

Mike Monett wrote:

Hi Wayne,

Raw hydrogen ions cannot exist naked in solution. They combine with
a nearby hydroxyl molecule to form H3O.

Of course, I should say a nearby water molecule. From Chemtutor:

"In a way, there is no such thing as a hydrogen ion or proton
without anything else. They just don't exist naked like that in
water solution. Remember that water is a very polar material.
There is a strong partial negative charge on the side of the
oxygen atom and a strong partial negative charge on the hydrogen
side. Any loose hydrogen ion, having a positive charge, would
quickly find itself near one of the oxygens of a water molecule.
At close range from the charge attraction, the hydrogen ion would
find a pair (its choice of two pairs) of unshared electrons around
the oxygen that would be capable of filling the its outer shell.
Each hydrogen ion unites with a water molecule to produce a
hydronium ion, H3O+, the real species that acts as acid. The
hydroxide ion in solution does not combine with a water molecule
in any similar fashion. As we write reactions of acids and bases,
it is usually most convenient to ignore the hydronium ion in favor
of writing just a hydrogen ion."

http://www.chemtutor.com/acid.htm

Mike Monett

 

[Borek]

On Mon, 11 Jul 2005 12:48:38 +0200, <rekuci@gmail.com> wrote:

The reason is probably because H+ *does* move faster than OH-. H+ has
a limiting ionic conductivity of about 350 S.cm^2/eq and OH- has a

Adding to all other replies: universal indicator response is not
necessarilly linear, so I doubt you are really able to tell what
pH and pOH are at which solution place.

Best,
Borek
--
http://www.chembuddy.com - chemical calculators for labs and education
BATE - program for pH calculations
CASC - Concentration and Solution Calculator
pH lectures - guide to hand pH calculation with examples

 

[Mike Monett]

WAYNEL wrote:

Hi Mike

Thanks for your detail response. I have re-run the test using graphite
electrode and 18.3MG pure water with Universal Indicator. I get the
same results. From what you are saying I guess the H+ ion and the OH-
ions are attaching themselves to something in the Universal Indicator?

Cheers

Wayne

Hi Wayne,

Yes, graphite definitely eliminates the copper electrolysis problem

As you point out, and another poster mentions, the effect may be due to
the indicator. It might be nice to try the experiment in a shot glass to
get a larger volume and work in 3D instead of a thin film.

Another thing you might consider is using plain red cabbage juice. If you
get it right, you can end up with wisps of indicator scattered through
the solution, with pure dw in between. The wisps of indicator will light
up as the various ion species cross them. The hydroxyl ion causes the
solution to turn purple, but I don't know what H3O(+) would do. This
should allow you to estimate the diffusion rate in pure water with less
interference from possible reactions with the indicator.

You can use the Faraday calculations mentioned in my earlier post to
calculate the number of ions in solution. If so, you need to use a
constant current source (perhaps 100uA to 10mA) with sufficient voltage
compliance to prevent saturating, and change the Faraday constant from
copper to whatever ion you are interested in tracking.

Interesting experiment! Let us know your results.

Mike Monett

 

In sci.electronics.repair Kathleen Carmody <councilmembercarmody@ci.brooklyn-center.mn.us> wrote:

: (-PLEASE- No lectures or legal suppositions needed or desired)

: Anyone know where to purchase a cellular phone jammer, preferably
: stateside. There are vendors off shore, but none here in CONUS
: that I know of. Please post here any US vendors that sell cellular
: jammers. (Extra points for relating your experience with using one.)


They're illegal to sell in the US but if you google "cellphone jammer" you'll
find some.

b.

 

[Mike Monett]

WAYNEL wrote:

Hi Mike

What group are you answering from?

sci.chem?

Hi Wayne,

s.e.d.

I check sci.chem from time to time. They have a few good people, but if
they are not active there's little else worth reading. Pretty much the
same as here on s.e.d.

What prompts you to investigate the mobility of hydroxyl and H3O+ ions?
This can turn into very interesting research. Water seems so simple, but
it has to be one of the most complex substances on the planet. For
example, you probably have seen "The anomalous properties of water", at

http://www.lsbu.ac.uk/water/anmlies.html

There are a few movies on the web showing electrolysis of water. Here's
one using phenolphthalein as an indicator. It's pretty crude, but it
might give you something to compare with your results. The url is

http://chemmovies.unl.edu/chemistry/videos/SS017PhetoKI.mov (560k)

It is from Step 3 at:

http://chemmovies.unl.edu/chemistry/smallscale/SS017c.html

Mike Monett

 

[Watson A.Name - \"Watt Su]

"Fred McKenzie" <fmmck@aol.com> wrote in message
news:fmmck-0407052245300001@ac93c3e9.ipt.aol.com...

In article <42BFD985.53E27BE9@yahoo.com>, Ron Thompson
rthompso6161@yahoo.com> wrote:

Does anyone know of a method of either locating or finding
information
about transistors that were manufactured in 1972? I am specifically
interested in locating or finding info on two transistors; their
codes
are: 2N5809 and 2N9614.

Ron-

Take another look. Could the second one be a 2N961A? I don't think
the
JEDEC numbers were that high in the early 70s.

Fred

My old '69 Motorola Manual stops at the 2N5500 point. The 2N5809 might
be a valid number for that time period. But it's not in the Moto
manual. :-(

 

[Aubrey McIntosh, Ph.D.]

Mike Monett wrote:

WAYNEL wrote:

Hi Mike

What group are you answering from?

sci.chem?


Hi Wayne,

s.e.d.

I check sci.chem from time to time. They have a few good people, but if
they are not active there's little else worth reading. Pretty much the
same as here on s.e.d.

What prompts you to investigate the mobility of hydroxyl and H3O+ ions?
This can turn into very interesting research. Water seems so simple, but
it has to be one of the most complex substances on the planet. For
example, you probably have seen "The anomalous properties of water", at

http://www.lsbu.ac.uk/water/anmlies.html

There are a few movies on the web showing electrolysis of water. Here's
one using phenolphthalein as an indicator. It's pretty crude, but it
might give you something to compare with your results. The url is

http://chemmovies.unl.edu/chemistry/videos/SS017PhetoKI.mov (560k)

It is from Step 3 at:

http://chemmovies.unl.edu/chemistry/smallscale/SS017c.html

Mike Monett

Another indicator that might be interesting is disodium fluorescein.
This is the stuff that makes antifreeze the dayglow green color. It is
safe enough to inject into blood or pour into rivers for tracing.

It changes from an extreemly efficient fluorescent dye to colorless and
non-fluorescent when it gets protonated.

 

[Mike Monett]

Aubrey McIntosh, Ph.D. wrote:

[...]

Another indicator that might be interesting is disodium fluorescein.
This is the stuff that makes antifreeze the dayglow green color. It is
safe enough to inject into blood or pour into rivers for tracing.

It changes from an extreemly efficient fluorescent dye to colorless and
non-fluorescent when it gets protonated.

Interesting. You mean I can go out to my car, drain some antifreeze, and
get a ph indicator? That would be nice.

I'm not sure what you mean by the word protenate in this context. Does it
mean the indicator responds only to hydronium ions, or would any
postive ion such as metal work?

Any other suggestions for cheap sensitive indicators, preferably ones you
can find in a grocery store or pharmacy on a weekend?

Mike Monett

 

[Aubrey McIntosh, Ph.D.]

Mike Monett wrote:

Aubrey McIntosh, Ph.D. wrote:

[...]



Interesting. You mean I can go out to my car, drain some antifreeze, and
get a ph indicator? That would be nice.

I'm not sure what you mean by the word protenate in this context. Does it
mean the indicator responds only to hydronium ions, or would any
postive ion such as metal work?

Any other suggestions for cheap sensitive indicators, preferably ones you
can find in a grocery store or pharmacy on a weekend?

Mike Monett

Not all antifreeze use this same dye, but in principle, yes. As an
aside, when ethylene glycol (of antifreeze) oxidizes it can make oxalic
acid. Oxalic acid and iron can proceed to make "greensalt" which is
almost the same color as antifreeze with the disodium fluorescein.

Most pH indictors are discussed in the context of either H+ or Na+ (OH-
in water, with Na+ as a spectator ion) If metals that are not in the
first two columns are used, you results have a lot more nuance than the
standard language provides. For example, when I cook cabbage in an
aluminum container, the color is off, and the container shows signs that
some aluminum oxide is removed. I assume that the Al+3 is being
complexed by the dye in the cabbage, but this is anecdotal -- I haven't
collected data.

One easy dye to obtain is the broth from cooking red cabbage. It is red
when acidic, blue when basic, and lavender in betwixt.

Bromthymol blue is another easy to obtain pH indicator. It is sold in
aquarium shops as a treatment for "ick."

Litmus paper itself uses the juice from lichens. It sticks in my mind
that the Scientific American "Connections" column attributes Litmus
paper to a McIntosh in Scotland.

Beet juice is mentioned at http://www.purchon.com/chemistry/ph.htm but I
have not tried it. I do know that when beets are cut into 1/4" cubes
and cooked while protected from air in a pressure cooker, the juice is a
dayglow red. I speculate that this is pH sensitive, I just haven't had
the desire to add lye or battery acid to my beets.

Other foods: cranberry, elderberry, tumeric, grape, and blueberry are
mentioned at http://www.vanderbilt.edu/vsvs/
lesson_plans/NaturalIndicators.doc

 

[sofie]

the 2n5809 is not a transistor but rather a hefty stud mount Triac, if my
memory serves me... around 30 or 40 Amps.
the 2n961 is an RF/IF PNP Germanium transistor, metal can TO18... I used
them in some ham radio projects in the late 60's.
..... there is no 2n9614.... check the number again.
--
Best Regards,
Daniel Sofie
Electronics Supply & Repair
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -


"Watson A.Name - "Watt Sun, the Dark Remover"" <NOSPAM@dslextreme.com> wrote
in message news:11d7f1dffdhl672@corp.supernews.com...

"Fred McKenzie" <fmmck@aol.com> wrote in message
news:fmmck-0407052245300001@ac93c3e9.ipt.aol.com...
In article <42BFD985.53E27BE9@yahoo.com>, Ron Thompson
rthompso6161@yahoo.com> wrote:

Does anyone know of a method of either locating or finding
information
about transistors that were manufactured in 1972? I am specifically
interested in locating or finding info on two transistors; their
codes
are: 2N5809 and 2N9614.

Ron-

Take another look. Could the second one be a 2N961A? I don't think
the
JEDEC numbers were that high in the early 70s.

Fred

My old '69 Motorola Manual stops at the 2N5500 point. The 2N5809 might
be a valid number for that time period. But it's not in the Moto
manual. :-(

 

[John Beardmore]

In message <1121012726.743338.221040@g47g2000cwa.googlegroups.com>,
WAYNEL <mail@wlawson.com> writes

I've conducted a simple experiment on a glass sample that has two clean
copper electrodes biased with 20v DC. Between the two electrodes I
have placed a drop of de-ionised water with Universal Indicator added.

Over a period of time the electrodes changes colour, as expected, with
the cathode going purple (OH-) and the anode going red (H+).

After a longer period of time the colours start to spread out toward
the opposing electrodes, pH gradient. However, the amount the purple
(OH-)spreads is apx three times greater that that of the red (H+).

I have repeated this 10 times in random positions and I get the same
results.

I would have thought that the H+ ions would have more mobility than the
OH- ions and thus I would have expected the opposite to happen.

Can anyone help and through some light on this phenomena, or have I
missed something?

What is the effect of the charge gradient on the constituents of the
indicator itself ?


Cheers, J/.
--
John Beardmore

 

[Mike Monett]

Aubrey McIntosh, Ph.D. wrote:

[...]

Not all antifreeze use this same dye, but in principle, yes. As an
aside, when ethylene glycol (of antifreeze) oxidizes it can make oxalic
acid. Oxalic acid and iron can proceed to make "greensalt" which is
almost the same color as antifreeze with the disodium fluorescein.

Most pH indictors are discussed in the context of either H+ or Na+ (OH-
in water, with Na+ as a spectator ion) If metals that are not in the
first two columns are used, you results have a lot more nuance than the
standard language provides. For example, when I cook cabbage in an
aluminum container, the color is off, and the container shows signs that
some aluminum oxide is removed. I assume that the Al+3 is being
complexed by the dye in the cabbage, but this is anecdotal -- I haven't
collected data.

One easy dye to obtain is the broth from cooking red cabbage. It is red
when acidic, blue when basic, and lavender in betwixt.

Bromthymol blue is another easy to obtain pH indicator. It is sold in
aquarium shops as a treatment for "ick."

Litmus paper itself uses the juice from lichens. It sticks in my mind
that the Scientific American "Connections" column attributes Litmus
paper to a McIntosh in Scotland.

Beet juice is mentioned at http://www.purchon.com/chemistry/ph.htm but I
have not tried it. I do know that when beets are cut into 1/4" cubes
and cooked while protected from air in a pressure cooker, the juice is a
dayglow red. I speculate that this is pH sensitive, I just haven't had
the desire to add lye or battery acid to my beets.

Other foods: cranberry, elderberry, tumeric, grape, and blueberry are
mentioned at http://www.vanderbilt.edu/vsvs/
lesson_plans/NaturalIndicators.doc

Thanks for the good info. Incidentally, red cabbage turns very deep
purple when exposed to OH(-) ions, and very faint white with AG(+) ions.

Mike Monett

 

[Rich Grise]

On Sun, 10 Jul 2005 09:25:26 -0700, WAYNEL wrote:

I've conducted a simple experiment on a glass sample that has two clean
copper electrodes biased with 20v DC. Between the two electrodes I
have placed a drop of de-ionised water with Universal Indicator added.

Over a period of time the electrodes changes colour, as expected, with
the cathode going purple (OH-) and the anode going red (H+).

After a longer period of time the colours start to spread out toward
the opposing electrodes, pH gradient. However, the amount the purple
(OH-)spreads is apx three times greater that that of the red (H+).

I have repeated this 10 times in random positions and I get the same
results.

I would have thought that the H+ ions would have more mobility than the
OH- ions and thus I would have expected the opposite to happen.

Can anyone help and through some light on this phenomena, or have I
missed something?

I suspect you've got some dissolved copper in there, in some
form. What happens if you use gold-plated electrodes, like wire-wrap
pins?

Thanks,
Rich

 

[Marvin]

John Beardmore wrote:

In message <1121012726.743338.221040@g47g2000cwa.googlegroups.com>,
WAYNEL <mail@wlawson.com> writes

I've conducted a simple experiment on a glass sample that has two clean
copper electrodes biased with 20v DC. Between the two electrodes I
have placed a drop of de-ionised water with Universal Indicator added.

Over a period of time the electrodes changes colour, as expected, with
the cathode going purple (OH-) and the anode going red (H+).

After a longer period of time the colours start to spread out toward
the opposing electrodes, pH gradient. However, the amount the purple
(OH-)spreads is apx three times greater that that of the red (H+).

I have repeated this 10 times in random positions and I get the same
results.

I would have thought that the H+ ions would have more mobility than the
OH- ions and thus I would have expected the opposite to happen.

Can anyone help and through some light on this phenomena, or have I
missed something?


What is the effect of the charge gradient on the constituents of the
indicator itself ?

If they are charged, they will migrate in a direction and at a rate depending on the gradient.

Cheers, J/.

 

[Rich Grise]

On Tue, 12 Jul 2005 10:58:31 -0400, Mike Monett wrote:

Aubrey McIntosh, Ph.D. wrote:

[...]

Another indicator that might be interesting is disodium fluorescein.
This is the stuff that makes antifreeze the dayglow green color. It is
safe enough to inject into blood or pour into rivers for tracing.

It changes from an extreemly efficient fluorescent dye to colorless and
non-fluorescent when it gets protonated.

Interesting. You mean I can go out to my car, drain some antifreeze, and
get a ph indicator? That would be nice.

I'm not sure what you mean by the word protenate in this context. Does it
mean the indicator responds only to hydronium ions, or would any
postive ion such as metal work?

Any other suggestions for cheap sensitive indicators, preferably ones you
can find in a grocery store or pharmacy on a weekend?

Do you mean besides red cabbage juice? That's almost free, and I saw a
demo on some TV show - either the science segment of some variety show,
or something like that Newton's Apple. Anyway, they juiced a cabbage,
and had about seven containers, where they put stuff like vinegar, and
drain cleaner, and ammonia, and various things, with different pH, and
that cabbage juice turned about seven different colors!

But then you have the same problem with all kinds of chemical compounds -
I think the indicator is called a "confounder".

Is there any such thing as a noninvasive pH meter?

Thanks,
Rich

 

[Rich Webb]

On Wed, 6 Jul 2005 08:38:06 +0100, "Dave Garnett"
<dave.garnett@metapurple.co.uk> wrote:

Hi,
I need program ATmega8. Is ISP load cable will be enough for example:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50915&item=7529042935&rd=1&ssPageName=WDVW
or I need something else ?

It might work, but I'd spend the money to get a 'real' Atmel AVRISP. I note
that the firmware for it seems to get updated with each release of the AVR
Studio, and I'd wonder about support coming from anyone except Atmel ... My
experience of third party ISP programmers has been mixed, with particular
problems at lower voltages.

And if you add a suitable header to your project you don't need anything
else to program it - but you'd better read the programming section of the
datasheet carefully to make sure that you don't get any clashes with your
logic.

Also, the OP should read the datasheet carefully with respect to the
default chip configuration, since it sounds like he's never programmed
one before. He should note that the default fuse setting on virgin
ATmega8 chips is to run from the internal RC oscillator at 1 MHz. This
frequently (no pun intended (yeah, right)) leads to two problems:

Trying to program it via ISP with a serial clock faster than 250 KHz may
(and probably will) fail. This may lead one to believe that the chip is
faulty, or the ISP programmer is faulty, or the circuit is bad, or ...

If it does program, one might wonder why the device with the 16 MHz
crystal is running so damned slow and suspect a faulty chip, or bad
layout, or ...

The chip is shipped with those fuse settings so that it can be
programmed and used in non-time critical applications without any
external clock or crystal. It's very easy to set the fuses for an
external reference; also easy to forget to do so.

--
Rich Webb Norfolk, VA