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Sine to square wave converter
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John Woodgate
electronics forum Guru


Joined: 24 Mar 2005
Posts: 1546

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: Sine to square wave converter Reply with quote

I read in sci.electronics.design that Jack// ani
<nospam4u_jack@yahoo.com> wrote (in
<1111689339.387719.13490@o13g2000cwo.googlegroups.com>) about 'Sine to
square wave converter', on Thu, 24 Mar 2005:
Quote:
Thanks for reply Lord. Unfortunately link is dead!

IE6 barfs badly, but Firefox retrieves it OK. I'm having the same

problem with PDFs from other sites, using IE 6 and Acrobat 6.
--
Regards, John Woodgate, OOO - Own Opinions Only.
There are two sides to every question, except
'What is a Moebius strip?'
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
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Clarence_A
electronics forum addict


Joined: 02 May 2005
Posts: 66

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: Help - I can't solder tiny resistors! Reply with quote

"Bob" <nimby1_notspamm_@earthlink.net> wrote in message
news:MLNLd.3776$cl1.1951@newsread3.news.pas.earthlink.net...
Quote:
"it's" = "it is", or "it has"
"its" is for everything else.

I knew you really wanted to know.

:-)

Bob


Top poster PLONKED!
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Clarence_A
electronics forum addict


Joined: 02 May 2005
Posts: 66

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: software for circuits Reply with quote

"teranews" <lmcadmin@latexmaskcentral.com> wrote in message
news:1107312080.d6af5926f723580a459fb8840ab9ad93@teranews...
Quote:
Are there any free/shareware or inexpensive (under $100) sofware
packages
that let you design circuits and analyze various values (V,I,R
for instance)
at points in the circuit? I'm trying to learn and something
like this would
be invaluable to understanding.

thanks


"LTSpice" from Linear.com is free!
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petrus bitbyter
electronics forum Guru


Joined: 24 Mar 2005
Posts: 363

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: help pls!! memory address decoder design Reply with quote

"Kelvin@!!!" <kelvin604@shaw.ca.ca> schreef in bericht
news:Zx%Ld.250043$8l.167533@pd7tw1no...
Quote:
the question is
Design a decoder for the following using a "138 decoder, NAND gates, and
iinverters":
a 1K memory is connected to a 16 bit address but. the first location of
the memory is to be at 4000H. DO NOT use partial decoding. draw a decoder
circuit that gives an active low for these memory locations.

this is a review quiz i got today in my first microcontroller lecture.
my prof just gave us a super simple solution that totally confused me...

1K = 1024
A0 ~ A9 change
A10 ~ A15 decoded

i understand that 1024 = 2^10
so A0 ~ A9 is used for address.
but what does he meant by "A10 ~ A15 decoded"???

thnx for any help...
--
{ Kelvin@!!! }


Well, a 1k memory requires 10 address lines to access each address. So the
adress lines A0~A9 need to be connected to the memory chip. The first
address you need to decode is

0100 0000 0000 0000

and the last one

0100 0011 1111 1111

or generaly

0100 00xx xxxx xxxx

So you need to provide a chip select for the memory:

CS = /A15 + A14 + /A13 + /A12 + /A11 + /A10

This function does not fit in a 138 so you have to add some other logic.

Google for the LS138 or HCT138 to find out the possibilities of this chip.

Be warned that, although it is not mentioned in the exercise, in practice CS
lines are often activ low.

petrus bitbyter
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Blackbeard
electronics forum beginner


Joined: 24 Mar 2005
Posts: 9

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: TESLA COIL (0/1) Reply with quote

Thanks for giving me a heads up. I have posted out pics at
alt.binaries.schematics.electronics as you suggested.




On Mon, 31 Jan 2005 10:21:17 -0700, Mark Fergerson <nunya@biz.ness>
wrote:

Quote:
Blackbeard wrote:

Alright. You guys are talking over my head. Electronics is definitely
NOT something I am familiar with. So I figured I could attach the
pictures of what my son has completed so far.

Whoops! No binary attachments (pictures) allowed in this group.
Repost to alt.binaries.schematics.electronic and we'll take a look.

From what I gather, the only thing he has left to do is connect a
transformer and a spark gap.

OK, but we'd still like to take a gander to help make sure the thing
works, and he survives.

When we tested his spark gap by connecting one wire to one of the
copper pieces and the other wire from the transformer to the other
side, the sparks to jumped across. However, he used hot glue to hold
the copper pipe in place and the heat melted the hot glue. So we've
gotta re-think that plan.

Epoxy works too.

You could get mechanical about it. Take a look at the top couple of
pictures at this link:

http://users.tm.net/lapointe/SparkGap.htm

for ideas how to mount your pipe sections. Notice particularly that
sharp edges on the little brackets, bolt heads, and like that are kept
far apart (and the pipe is deburred) so that the sparks will "want" to
jump only between the pipes themselves. Oh, yeah; the gaps between the
sections ought to be a millimeter or so.

You won't have to get quite so ornate; I picked this page pretty much
at random from a Google search for "copper pipe" +"spark gap" to show
some typical general construction methods.

Here's another that uses a fan to blow out the arcs to prevent what's
called "power arcing" and provide some cooling:

http://users2.ev1.net/~nmyreality/tesla/sparkgap/rqgap.html

Power arcing is when the gaps are still firing after the cap has
discharged into the primary coil and the transformer is basically
shorted across the gap, wasting its power instead of feeding more into
the secondary. Getting the gaps to stop firing when the cap has
discharged is called "quenching" them. The idea is to feed energy into
the secondary in lumps (every time the line voltage peaks, 120 times a
second), not to try to do so continuously regardless of the fact that it
LOOKS like it's continuous. Power arcing just overheats the transformer,
but if your son's coil isn't drawing lots of power, and/or he doesn't
run it for more than a few minutes at a time, this may not be worth
worrying about.

If you can take a look at the pictures, maybe it will give you a
better idea of where he is and what he's trying to accomplish.

Sorry for my ignorance on all this stuff. If you have a plumbing
question, I'm your guy. Electronics...nada from me.

Ignorance is not knowing how far what you already know can be applied.

You know about water hammer, right? That's the exact same kind of
resonance principle that your son's coil will use, except with
electricity. When water hammer gets extreme pipes break. When his Tesla
coil works right, the toroid similarly breaks out in sparks.

One the pictures, the primary is made using 50-feet of 1/4OD
refrigerant tubing. The secondary is made by winding 24-gauge wire
approx. 1500 turns onto a piece of 4-inch pvc. The toroid is made from
a piece of semi-rigid duct attached to a 5-gallon bucket top. The
5-gallon bucket top/toroid uses an upside-down toilet flange to easily
attach to the extra pipe that runs through the center of his
secondary.

That primary seems to have way too many turns. <mumble> gotta see
that diagram...

I say that because like most electrical gear, a TC ought to be
designed and built from the business end backwards. You have your toroid
and secondary, which pretty much determines the frequency they'll run
at. You have a primary coil and its dimensions fix its inductance range,
so what's left is to figure out the capacitance the beer bottle cap will
need (how many bottles, how big a bucket) so the primary circuit can
resonate with the secondary circuit.

Then there's tuning the primary; this is analogous to adjusting the
lengths of the parts of a plumbing system to get the loudest water
hammer, but since the "customer" end is fixed you have to adjust the
"supply" end.

When everything's built and powered up, don't be surprised if he
doesn't get lightning right off the bat. It's really difficult to adjust
a beer bottle cap in small steps, so it's simpler to move the primary
connection ("tap") along the copper tubing to find the "sweet spot"
where the primary coil is in resonance with the secondary. This involves
connecting the wire to the copper tubing with something he can loosen,
slide along the tubing say an eighth of a turn at a time, then retighten
(the part of the tubing "hanging loose" doesn't affect the primary's
inductance). Some folks prefer modified fuse holders, other use a short
piece of copper pipe strap. Whichever, only move it when the system is
UNPLUGGED and he's shorted the primary capacitor to remove its charge.
The charge stored on it can KILL!

Your son will have to learn a little math and get familiar with some
equations to guess how much of his primary will resonate (where to put
the tap to get started) with the cap you end up using.

We are using a 15,000-volt neon transformer for power.

Is it an older one, or a newer one? The difference is that the newer
versions have "protection" devices built into them that make them almost
useless for TC use without surgery. If so, there's always microwave oven
transformers. Gutting a microwave isn't all that difficult, and they're
always available at yard sales.

For more details on that I really suggest the Tesla coil mailing list
archives, and/or a tour of the webring.

snip

How would one go about building a beer bottle cap?

Don Bruder gave good advice. I'd add that the hardware that actually
touches the salt water ought to be galvanized because salt water is
corrosive. One other thing; this is for a school project and they might
or might not get a little cranky if the bottles are identified by their
previous contents. ;>)

Mark L. Fergerson
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Blackbeard
electronics forum beginner


Joined: 24 Mar 2005
Posts: 9

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: TESLA COIL (0/1) Reply with quote

Sounds like you either need to install a hammer arrester or a pressure
reducing valve. You can buy a hammer arrester that will screw right
onto the threads of your stop vavle. Then you connect your water
supply tube to the auxilliary threads on the the new hammer arrester.
That's probably your cheapest solution. The threaded hammer arrester
will cost you approx. $20. I would try the hammer arrester. If that
works, don't worry about that PRV



On 1 Feb 2005 18:22:24 -0800, "Bill Bowden" <wrongaddress@att.net>
wrote:

Quote:
If you have a plumbing question, I'm your guy.
Electronics...nada from me.

I have a plumbing question. I get this loud humming
noise from my water pipes when I shut off the water
after taking a shower. I can't find any leaks and if
I flush the toilet, the noise goes away and doesn't return
until next time I run the hot water for some time.
Any idea what is going on with the water pipes?

-Bill
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Blackbeard
electronics forum beginner


Joined: 24 Mar 2005
Posts: 9

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: TESLA COIL (0/1) Reply with quote

So where would I purchase two of those "bullet proof" caps. Sounds
like that might be the best way to go. May not have time to find them
and use them before his science fair is due (Feb 17th). But if he gets
wimpy streamers, I'm sure he'll want to mess with this thing to get
more bang for his buck.

He's also been very impressed with pictures of people somehow routing
the lightening through their bodies and shooting bolts of lightening
from their fingerstips. He's found pics on the internet where people
have done that. I told him we had no way to test the current and no
equipment to check if it would be safe (basically, keep your grubby
hands off). It is my understanding that at the high voltage, it would
kill him so fast he'd never know he'd been zapped. He's already been
bitten by that transformer. It made an impression. He's been a lot
more careful since that transformer bit him



On Tue, 01 Feb 2005 09:18:15 -0700, Mark Fergerson <nunya@biz.ness>
wrote:

Quote:
Vidor Wolfe wrote:
"Mark Fergerson" <nunya@biz.ness> wrote in message
news:bOtLd.4534$6u.1006@fed1read02...

Blackbeard wrote:

Snipped...

We are using a 15,000-volt neon transformer for power.

Is it an older one, or a newer one? The difference is that the newer
versions have "protection" devices built into them that make them almost
useless for TC use without surgery. If so, there's always microwave oven
transformers. Gutting a microwave isn't all that difficult, and they're
always available at yard sales.

Another excellent transformer is the OBIT (Oil Burner Ignition Transformer.)
Generally 10KV at 20+mA and to my mind, "bullet proof!"
I've used two 10KV at 23mA in parallel on a 4" coil and gotten 30"
streamers.

Yeah, I forgot about those. Bullet-proof indeed; I managed to short
one with a really poorly-built Jacob's ladder, but it worked fine after
I unscrewed the mechanical setup.

How would one go about building a beer bottle cap?

Don Bruder gave good advice. I'd add that the hardware that actually
touches the salt water ought to be galvanized because salt water is
corrosive. One other thing; this is for a school project and they might
or might not get a little cranky if the bottles are identified by their
previous contents. ;>)

And watch out for Hydrogen generation in the caps...

Right. Bubbles are Bad Signs.

Further to my previous postings, MMC (Multi Mini Capacitor) are really the
cheapest, most reliable way to go with an almost home made cap.

Yeah, but bottle dielectric punctures are easier to fix. ;>)

Not that I'm trying to stop an experiment, but I've never had brilliant
results with beer bottle or glass plate caps.

It's a school project. Explaining its failure modes is better than
having it work perfectly and not being able to explain why.

Mark L. Fergerson
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Lord Garth
electronics forum Guru


Joined: 24 Mar 2005
Posts: 363

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: help pls!! memory address decoder design Reply with quote

"petrus bitbyter" <p.kralt@reducespamforchello.nl> wrote in message
news:a%4Md.76118$PH1.46797@amsnews05.chello.com...

Quote:

Well, a 1k memory requires 10 address lines to access each address. So the
adress lines A0~A9 need to be connected to the memory chip. The first
address you need to decode is

0100 0000 0000 0000

and the last one

0100 0011 1111 1111

or generaly

0100 00xx xxxx xxxx

So you need to provide a chip select for the memory:

CS = /A15 + A14 + /A13 + /A12 + /A11 + /A10

This function does not fit in a 138 so you have to add some other logic.

Google for the LS138 or HCT138 to find out the possibilities of this chip.

Be warned that, although it is not mentioned in the exercise, in practice
CS
lines are often activ low.

petrus bitbyter

CS is to be active low. The 6 upper address lines are not OR'd together.
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Andrew Holme
electronics forum Guru Wannabe


Joined: 29 Apr 2005
Posts: 272

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: help pls!! memory address decoder design Reply with quote

Kelvin@!!! wrote:
Quote:
the question is
Design a decoder for the following using a "138 decoder, NAND gates,
and
iinverters":
a 1K memory is connected to a 16 bit address but. the first location
of the
memory is to be at 4000H. DO NOT use partial decoding. draw a decoder

circuit that gives an active low for these memory locations.

this is a review quiz i got today in my first microcontroller
lecture.
my prof just gave us a super simple solution that totally confused
me...

1K = 1024
A0 ~ A9 change
A10 ~ A15 decoded

i understand that 1024 = 2^10
so A0 ~ A9 is used for address.
but what does he meant by "A10 ~ A15 decoded"???

thnx for any help...
--
{ Kelvin@!!! }

You want 0100 00xx xxxx xxxx

The 138 has 3 enables: G1, G2A, G2B.

G1 is active high.
G2A/B are active low.

You could feed the top 3 address lines to the enables and the next 3
address lines to the ABC inputs:

G2A = A15
G1 = A14
G2B = A13
C = A12
B = A11
A = A10

This way, output Y0 would be your RAM chip select:

Y0 = 0100 00xx xxxx xxxx
Y1 = 0100 01xx xxxx xxxx
Y2 = 0100 10xx xxxx xxxx
Y3 = 0100 11xx xxxx xxxx
Y4 = 0101 00xx xxxx xxxx
Y5 = 0101 01xx xxxx xxxx
Y6 = 0101 10xx xxxx xxxx
Y7 = 0101 11xx xxxx xxxx

You don't need any extra gates.
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Mark Fergerson
electronics forum Guru Wannabe


Joined: 06 May 2005
Posts: 196

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: TESLA COIL (0/1) Reply with quote

Blackbeard wrote:
Quote:
So where would I purchase two of those "bullet proof" caps. Sounds
like that might be the best way to go. May not have time to find them
and use them before his science fair is due (Feb 17th). But if he gets
wimpy streamers, I'm sure he'll want to mess with this thing to get
more bang for his buck.

Sorry, should have been clearer. We were talking about a transformer
that's found in home heating systems that burn fuel oil (hence the name,
Oil Burning Ignition Transformer, or OBIT). It provides high voltage
from line voltage like neon or microwave oven transformers (MOTs), but
with more current capability, and they're more tolerant of situations
that draw lots of current without catastrophic failure, hence
"bulletproof". That greater current that most neon or MOTs means they
should be handled with extra care.

Quote:
He's also been very impressed with pictures of people somehow routing
the lightening through their bodies and shooting bolts of lightening
from their fingerstips. He's found pics on the internet where people
have done that. I told him we had no way to test the current and no
equipment to check if it would be safe (basically, keep your grubby
hands off). It is my understanding that at the high voltage, it would
kill him so fast he'd never know he'd been zapped.

NO!!! DO NOT LET HIM DO THIS!!! Better he takes up ballet or something.

There was a guy who knew exactly what he was doing, giving
performances including this same "trick". He took every possible
precaution and still got killed in front of an audience. All it takes is
one tiny mistake.

Quote:
He's already been
bitten by that transformer. It made an impression. He's been a lot
more careful since that transformer bit him

Good! Pain tells us not to do that again! The guy that died was
operating a fairly large coil running hundreds of watts. As long as
you're using a neon or MOT, getting zapped by the TC's output should be
shocking, but not fatal. Just don't tempt fate. Remind your son that
OBIT also stands for obituary.

BTW, I can't find your schematic on a.b.s.e. What title did you use?

Mark L. Fergerson
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Dominic-Luc Webb
electronics forum beginner


Joined: 24 Mar 2005
Posts: 15

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: PCB etchants Reply with quote

On Sun, 23 Jan 2005, it was written:

Quote:
I keep reading on various websites that 'Persulphate' is a better etchant
than Ferric Chloride from Radio Shack, but I don't know how strong to mix
it and cannot seem to find any actual formulae.

I have, as it happens, plenty of both Ammonium and Potassium Persulphate,
and have tried mixing what I thought was a strongish solution of each,
but it seems very slow compared to Ferric Chloride. I did heat it, and
agitated the dish constantly, and the Potassium salt did go a bit blue,
but slow...slow...slow!


Yes, if you are still in here to read this, the ammonium persulphate can
be a bit slow, but it is much more gentle on the circuit pattern,
including lines drawn by "permanent" markers. Outgassing is also less
problematic. Reaction is concentration dependent. For a small double
sided board around 4x3 cm, I use around a heaping teaspoon and heat to
about 70 C. I just wait it out, as I am not usually in a big hurry and
am more concerned about a quality etch, and also environmental/health
issues in using some of the alternatives.

Dominic
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petrus bitbyter
electronics forum Guru


Joined: 24 Mar 2005
Posts: 363

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: help pls!! memory address decoder design Reply with quote

"Lord Garth" <LGarth@Tantalus.net> schreef in bericht
news:ev6Md.22634$wi2.2257@newssvr11.news.prodigy.com...
Quote:

"petrus bitbyter" <p.kralt@reducespamforchello.nl> wrote in message
news:a%4Md.76118$PH1.46797@amsnews05.chello.com...


Well, a 1k memory requires 10 address lines to access each address. So
the
adress lines A0~A9 need to be connected to the memory chip. The first
address you need to decode is

0100 0000 0000 0000

and the last one

0100 0011 1111 1111

or generaly

0100 00xx xxxx xxxx

So you need to provide a chip select for the memory:

CS = /A15 + A14 + /A13 + /A12 + /A11 + /A10

This function does not fit in a 138 so you have to add some other logic.

Google for the LS138 or HCT138 to find out the possibilities of this
chip.

Be warned that, although it is not mentioned in the exercise, in practice
CS
lines are often activ low.

petrus bitbyter

CS is to be active low. The 6 upper address lines are not OR'd together.




You are right if you consider the plus sign an OR which is usually done. I
also use to write the * for AND and the + for an OR but the other day I had
to work with a text that used the + for an AND and a | for the OR. Very
uncommon but that's why I was mistaken. So you have to read :

CS = /A15 * A14 * /A13 * /A12 * /A11 * /A10

petrus bitbyter
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Don Bruder
electronics forum Guru Wannabe


Joined: 03 May 2005
Posts: 190

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: TESLA COIL (0/1) Reply with quote

In article <l9r1011h64k52sk4lei7mnmch02qdii4et@4ax.com>,
Blackbeard <Blackbeard_The_Great@Lycos.com> wrote:

Quote:
So where would I purchase two of those "bullet proof" caps. Sounds
like that might be the best way to go. May not have time to find them
and use them before his science fair is due (Feb 17th). But if he gets
wimpy streamers, I'm sure he'll want to mess with this thing to get
more bang for his buck.

He's also been very impressed with pictures of people somehow routing
the lightening through their bodies and shooting bolts of lightening
from their fingerstips.

Special protective gear and specific knowledge allows that. Even with
the right stuff and the proper know-how, one tiny mistake and you're
suddenly either very dead, or reduced to the mental capacity of an
eggplant, the mobility of a rock, and breathing only with the help of a
respirator.

He's found pics on the internet where people
Quote:
have done that. I told him we had no way to test the current and no
equipment to check if it would be safe (basically, keep your grubby
hands off).

Good concept until he knows a *WHOLE LOT* more than he currently (no pun
intended, but since it's there...) does.

Quote:
It is my understanding that at the high voltage, it would
kill him so fast he'd never know he'd been zapped. He's already been
bitten by that transformer. It made an impression. He's been a lot
more careful since that transformer bit him

The frequency makes it safer - Note *SAFER*, not *SAFE* - to be messing
with it, but the voltages and current levels involved are more than
capable of killing if there's even a small mistake.

--
Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004.
Short form: I'm trashing EVERY E-mail that doesn't contain a password in the
subject unless it comes from a "whitelisted" (pre-approved by me) address.
See <http://www.sonic.net/~dakidd/main/contact.html> for full details.
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Markan
electronics forum beginner


Joined: 24 Mar 2005
Posts: 1

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: Simple Lie Detector with Digital Panel Meter Reply with quote

Robert Monsen <rcsurname@comcast.net> wrote in
news:XNqdnVWZ2Yr2K23cRVn-vg@comcast.com:

Quote:
Markan wrote:
Hi

I am looking for a simple lie detector cicruit for my son's science
project. We have a Digital Panel Meter with a 0-200Mv range. The
resistance we would like to measure would be about 0.2 - 2Mohms.

This does not need to be accurate. Help would be appreciated on how
to find a suitable circuit diagram.

Thanks

Markan

If you put a 10M resistor in series, and use a 1.2V source (actually,
a 1.5V battery would work fine), you'll get 200mV when the resistance
is 2M, and about 23mV when it's at 200k ohms. That sounds about right.

However, your digital panel meter may have a low resistance itself,
thus messing with the reading. Hopefully, it will have a 10M or higher
resistance, so it won't interfere too much. If it interferes too much,
come back and somebody will help you build a buffer to measure the
voltage with.

HOwever, I think this circuit will be fine. Use courier font, or other
monospaced font to view.

10MEG
___ +
.--|___|---o------o Probe1
| |
| |
| |
| / \ Meter
1.5V --- (_/_)
- \_/
| | -
'----------o------o Probe2

(created by AACircuit v1.28 beta 10/06/04 www.tech-chat.de)

If you need to power the meter, use separate batteries.


Robert

Thank you this works great!

Mark
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Blackbeard
electronics forum beginner


Joined: 24 Mar 2005
Posts: 9

PostPosted: Thu Mar 24, 2005 6:01 pm    Post subject: Re: TESLA COIL (0/1) Reply with quote

I posted those pics in
alt.binaries.schematics.electronic
titled Tesla Coil Science Fair Project

I wish I knew more about how to help the kid succeed. He's had a
fairly tough tumble through school. He gets his attention by showing
his ass. He's never received any recognition for doing good work.
That's why I'm bugging you guys. If this thing works for him, this
will be the first time in his life that he'll get to experience real
pride up close and personal. I'm keeping my hands off this one and
just sorta guiding him along the best I can. When he flips that switch
and at the science fair, I think he's going to get their attention. It
could be the start of this kid realizing that real praise feels pretty
damn good vs. the snickering approval he gets from his classmates for
making an ass out of himself.

At this point, I think we have the thing just about finished. He's
wrapped 6 beer bottles with aluminum foil and filled them with salt
water topped with oil. He re-did the spark gap with 2-mm of space
between each piece of copper. I think all he has to do now is run a
little wiring and turn it on.

Anything special I need to know? Can he turn this thing on inside the
house or do we need to carry it out into the yard and use a drop cord?
After he turns it on, what should we expect? Will it take a few
minutes to fire up or will it start shooting sparks pretty quick? I'm
pretty excited for the kid. I sure as hell hope he pulls it off.

thanks for all the assistance you guys have offered. It's helped fill
in the blank spots.

On Wed, 02 Feb 2005 09:39:48 -0700, Mark Fergerson <nunya@biz.ness>
wrote:

Quote:
Blackbeard wrote:
So where would I purchase two of those "bullet proof" caps. Sounds
like that might be the best way to go. May not have time to find them
and use them before his science fair is due (Feb 17th). But if he gets
wimpy streamers, I'm sure he'll want to mess with this thing to get
more bang for his buck.

Sorry, should have been clearer. We were talking about a transformer
that's found in home heating systems that burn fuel oil (hence the name,
Oil Burning Ignition Transformer, or OBIT). It provides high voltage
from line voltage like neon or microwave oven transformers (MOTs), but
with more current capability, and they're more tolerant of situations
that draw lots of current without catastrophic failure, hence
"bulletproof". That greater current that most neon or MOTs means they
should be handled with extra care.

He's also been very impressed with pictures of people somehow routing
the lightening through their bodies and shooting bolts of lightening
from their fingerstips. He's found pics on the internet where people
have done that. I told him we had no way to test the current and no
equipment to check if it would be safe (basically, keep your grubby
hands off). It is my understanding that at the high voltage, it would
kill him so fast he'd never know he'd been zapped.

NO!!! DO NOT LET HIM DO THIS!!! Better he takes up ballet or something.

There was a guy who knew exactly what he was doing, giving
performances including this same "trick". He took every possible
precaution and still got killed in front of an audience. All it takes is
one tiny mistake.

He's already been
bitten by that transformer. It made an impression. He's been a lot
more careful since that transformer bit him

Good! Pain tells us not to do that again! The guy that died was
operating a fairly large coil running hundreds of watts. As long as
you're using a neon or MOT, getting zapped by the TC's output should be
shocking, but not fatal. Just don't tempt fate. Remind your son that
OBIT also stands for obituary.

BTW, I can't find your schematic on a.b.s.e. What title did you use?

Mark L. Fergerson
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