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Sunantoro,

By connecting three batteries of larger amperage say 60, we can make our own
light duty welding tool.

I'm not sure I would want to use batteries for welding. First off I don't think a 60 Amp capacity is
enough. Secondly lead acid batteries produce hydrogen. Can you say 'Hindenberg' boys and girls? To be
honest, I have never had a need to do any arc welding so I have never investigated that option.

Jim

I'm not so sure this is the case. I'm now leaning towards no electrons
stored on the plates, but the "charge" is stored in the field, which is then
able to induce a current in the plates when it collapses (when it is
"discharged".

Electrons are stored in plates.
If the charge between the two plates is different, then an
electrostatic field is created. It's electrostatic because there is no
movement of charges (the charges are static).

You can think of the field like gravity. The charges are like mass.
If there are two bodies with mass, then a gravitational field is
created between them.

Paul

angtengchat,

I repair very high power-voltage equipment and so far I've not used gloves/
What i did was to use a ground stick and make sure I discharge the capacitance
voltages that were "trapped" before I actually use my hands to service the
equipment.

I wonder whether you dead short those capacitors or does your ground stick have
some resistance?

However at times, we still need to "check" the equiments while the equipment
is running, thats where the danger lies. Obviously an insulated mat won't
help much.

Actually the insulated mat thing only applies when working with power sources
that have a ground reference. Not that you shouldn't use one anytime you work
with high voltage but I don't think the mat makes much difference if the voltage
in question is floating.

After reading your thread, I guess one just have to be extra careful when
dealing with these high power-voltages equipments. Once is enough!

I think that it is good to understand the risks if they are inevitable, as when
you must take high voltage measurements. Knowing not only the maximum danger,
but the limits to danger can help make the task easier. We don't need
unnecessary stress, that leads to accidents. So does careless haste. The brain
should always be in gear before the hands (and other body parts) are in motion.
The one hand rule is good, but sometimes it's difficult to connect a voltmeter
across devices with only one hand. Well insulated meter leads help. Sometimes
you can connect the clip leaded negative terminal before turning on the power so
that you CAN observe the one hand rule. Actually the only time I ever got
'bitten' in nearly twenty years as a broadcaster was from RF in an antenna
'doghouse'. We had to take the base current readings daily, later only weekly.
The meters have a shorting switch so that they are not in the circuit when not
being read. This is to protect against lightening damage. Anyway I was pushing
the shorting a stubborn shorting switch and my hand got close to a 'hot' metal
plate, RF hot. RF is a whole different animal and the one hand rule often
doesn't work. It will jump to your body whether you are grounded or not. At the
same time you can sometimes take thousands of volts of RF without injury. You
have probably seen the demonstrations of the Tesla coil and the person stands
with a metal rod and giant arcs jump to the rod. The rod is important because RF
can burn the skin, the rod takes the initial hit and distributes the current
across a larger area on the hands.

Jim

The humorous discussion of electricity sounds very much like it was written by our US writer Dave Barry. If you post something like this, it's always a good idea to tell us who the author is, if possible.

..................

Waves don't ordinarily mix because electric and magnetic fields are linear. Wave A + Wave B = Wave (A+B) = Wave A + Wave B. This means that Wave A and Wave B can pass through each other and emerge without having been altered. Flashlight beams do just this sort of thing, and you can do it with colored light. Pass a blue light beam through a yellow light beam, and you'll see a blue spot and a yellow spot exactly where they'd be if the other beam wasn't present. You _might_ see a green region where the beams are combined--I haven't tried this--but they'll emerge from the region without having been altered.

Now, there are a few instances where fields are not linear because of some strangeness in the medium. In such a case, one radio wave will indeed modulate another. However, this is generally rare and we must use a special mixing device to combine radio signals such that they modulate each other: just combining them at the junction of two wires won't do it.

In such a mixer, we run the signals through a device that is NON-linear, like a diode or a transistor that's biased into a non-linear region. Signals that are combined this way will modulate each other in a useful manner: you get 4 new signals from the process: one has a frequency equal to the sum of the original two signals, another is the difference signal, and we get the two original signals as well. We mix signals just this way in most radio equipment.

..................

Note that electric fields can exist without capacitor plates and magnetic fields can exist without current-conducting wires. We see such fields in radio waves.

.......................

Please try to delete the quoted material in your posts.

..........................

M Kinsler
512 E Mulberry St. Lancaster, Ohio USA 740 687 6368



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hey ,

won't the fpga controller slow...because it can't give the real-time
performance as the controller which you plan to make on it...(Just a
guess..never did a real FPGA programming...just simulated netlists.....)

Regards :-),

--himanshu sharma

Hey ,

Anything explodes...==(Bomb)

To make a bomb...Take a Capacitor..(Electrolytic....5 mu F , 12 Volts..)
and then charge it with a 30 volt battery from a safer distance...with in
few seconds it will explode..

You can actually make a fundu light show using such electrical
components...by off-course exploding them...

Boooooooommmmmm !!!:-)

Regards :-),

--himanshu sharma

angtengchat wrote:

1)????????? Whats the defination of a Bomb?
2)????????? How to make a bomb?

For educational sake only!

Thanks

This discusion is off topic and in light of recent events in America and
abroad I would apreciate it if the topic is droped. There are plenty of sites
dedicated to this sort of thing, or if you really want some good realiable
information go to your local library. Please do not pursue it here, this
forum is for Electronics discusion only.

)O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(??? )O(

???????????? The Sinister Dragon
???

Hey, Just because I'm EVIL,
???????????? Doesn't make me a bad person......????????? >:-)
???

Or because the charge passed "through" the outside of their body or because
they were standing on some sort of insulated surface (i.e. rubber soled
shoes) or for a number of other reasons. If the WHOLE amount of energy was
dissapated through the single person, then it would probably cause them to
litterally vaporise ... if I had a few minutes I would do the maths (i.e.
5,000,000V @ 5,000,000 Amperes = 25,000,000 W = enough energy to boil a LOT
of water = say 80 litres worth in a split second ....

The great majority of ex-people who have been struck by lightning are dead
(or so I'm led to believe).


Jon

--- In Electronics_101@y..., ron madelo <johnmadelz@y...> wrote:

hi, electronics and computer enginer i am still a
student taking electronics and communition 3rth year.
i am enteresting to joined that organization.
kindly send a responce so that i know what other
information.

thank you

__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.

Aditya,
How complex do you need the interface to be? There are a lot of ways
around your particular issue.

For simple bit bashing (to control an LCD panel etc) - the Parallel port can
be hard wired to your board - a few simple lines of code to 0x378 (LPT1:
address), you can do pretty much anything.

For more complex applications you will probably need some extra support
chips - not neccessarily a controller, but enough to give you some
addressing. The simplest way (without too many external components) would be
to use TWO parallel ports, one for addressing and one for data - that way
you get 11 data lines x 2k worth of address space ... how much more could
you ask for?

If you only need the demo board to be interfaced to a PC, personally I would
probably slap a PIC or a HC811 processor on a board, use two pins for a
serial interface and let the processor do the translations for you.

Depends on the application you have in mind really.

Regards,


Jonathan

Hi,
About the question "why waves don't mix up?"

Why this is putting it rather crudely but ... WAVES DO MIX UP!! What
happens is that after modulation of sound or picture, we generate what
is called as frequency band. The band is centered at the modulation
carrier frequency chosen, that is the tuning frequency of your radio
set.

Now suppose this band of frequencies is located from say 1.5MHz to
2.5MHz then there is no reason why the NOISE frequencies lying in this
band won't mix up.

Secondly, if somebody in some other station also moduates the band
with the same carrier frequency your station will get blocked if his
station is quite strong. THIS IS THE EXAMPLE OF WAVES GETTING MIXED
UP.

Practically it doesn't happen becoz every station has a dedicated band
of its own and cannot go beyond it.

regds,
Aditya

Hi,

So it takes power, and probably energy, i.e. power times time to do

work and

certainly to kill someone.

Think about lightning. Lightning has millions (10^6) of amperes of
current, several millions of volts of voltage, (sometimes measuring
650 Coulumbs of charge) ... still there are quite a lot of people who
turn up alive even after being hit by lightning. I think that is
becoz of the fraction of a second the charge passes through the body
of the person.

regds,
Aditya

Hi,
I am building a demo board which will be interfaced with the PC by
means of Parallel Port in EPP mode. My guess is that I will require a
IEEE 1284 compatible controller on the board to communicate with the
PC.

Now the board has a FPGA on it. My question is whether

1) it will be easier to program the FPGA to act like a controller? or
2) Buy an off-the-shelf IEEE 1284 compatible controller and program
the FPGA to operate in conjuction with this controller??


I have made an independent search of parallel port controllers and
found that CD1283 is the only controller which has a lot of material
available about. However CD1283 has a bit complicated architecture.
Is there any other/simpler/probably cheaper controller available??


thanx
aditya

hi, electronics and computer enginer i am still a
student taking electronics and communition 4rth year.
i am enteresting to joined that organization.
kindly send a responce so that i know what other
information.

thank you

__________________________________________________
Do You Yahoo!?
Make a great connection at Yahoo! Personals.

The definition of a bomb, or explosive device is basically a very fast
burning fuel/oxidiser mixture - a bomb doesn't "explode" as such, but burns
very quickly, thereby releasing enormous amounts of energy in a very short
time.

If you want to build one ... the theory of it is above - which, "for
education sake" is all you need - this is the wrong group for it anyway ...

1) Whats the defination of a Bomb?
2) How to make a bomb?

For educational sake only!

Thanks


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Sunan,
You want to Arc weld using batteries? Yes, it can be done, although it
should be reserved for emergencies only - lead acid batteries do not respond
well to being short circuited. To "make your own" mains welder ... that's a
different story entirely. Basically to weld with batteries, just hook up the
stick (electrode) to positive and the earth clamp to negative. It's
preferable to have a higher voltage as possible - say 3 x 12v batteries in
series (i.e. positive to negative).

There should also be some information on the home power site that I referred
you to earlier. If you have a look around a few 4x4 oriented sites, they
sometimes have some good information on the subject as well.

Regards,



Jonathan

I always thought that it was 'Milly' Amp! ;-)
Keith Messent, Skipton, UK

I used to have access, many, many years ago, to a so-called 'Sun-Ray'
mains-powered (230-250V) carbon-arc lamp in which when the carbon
electrodes were closed to strike the arc, the current surge was absorbed
by some heavy-gauge air-cored resistors, also mounted in the reflector
bowl, as 'ballast'. Perhaps the principle could be applied to a
battery pack to save it from the ill-effects of the direct short when
striking the welding arc!
Keith Messent, Skipton, UK

By connecting three batteries of larger amperage say 60, we can make our own
light duty welding tool.
Please somebody tell me of any website which teaches how to construct our
own electric welding tool.
Thankyou,
SUNAN