8 to 10 year old boy add 50 ft bell wire, steel bar, 1 1/2 volt battery
and some tacks. You have a electro magnet.
next 6 volt battery = lift more tacks
more bell wire added to coil = lift more tacks
learned more volts + bigger coil (more wire) = stronger electro magnet
searches garage for another battery and more bell wire but in stead
finds about 150 ft of 14 gauge insulated wire and a 110V male plug.
WOW a super magnet. can not wait to build this.
put it together plug it in sparks fly and fuse blows (thank God the fuse
did not have a penny behind it).
It took out the electricity in the kitchen and 2 other rooms, this was
20 years ago in an old house with old wiring.
Within a month of asking questions to people who were knowledgeable in
electricity I knew what I had done wrong and basics of Ohms Law.
I learned that I would always try to know what was going to happen when
I did something. No "lets turn this and see what happens"
> 8 to 10 year old boy add 50 ft bell wire, steel bar, 1 1/2 volt battery
> and some tacks. You have a electro magnet.
> next 6 volt battery = lift more tacks
> more bell wire added to coil = lift more tacks
> learned more volts + bigger coil (more wire) = stronger electro magnet
> searches garage for another battery and more bell wire but in stead
> finds about 150 ft of 14 gauge insulated wire and a 110V male plug.
> WOW a super magnet. can not wait to build this.
> put it together plug it in sparks fly and fuse blows (thank God the fuse
> did not have a penny behind it).
>
> It took out the electricity in the kitchen and 2 other rooms, this was
> 20 years ago in an old house with old wiring.
> Within a month of asking questions to people who were knowledgeable in
> electricity I knew what I had done wrong and basics of Ohms Law.
> I learned that I would always try to know what was going to happen when
> I did something. No "lets turn this and see what happens"
>
> John
OK, about 45 years ago... I build the Allied Radio Knight Kit AM
Broadcaster transmitter (two 50C5 tubes and a 12AX7). This was one of
those units with no power transformer. The tube filaments were in series
across the line. B+ was generated using a half wave selenium rectifier.
One side of the line (the neutral side) was tied to the metal chassis
(through the on/off switch so you got a choice as to whether the chassis
was hot when the unit was on or when it was off). I figured this thing'd
get out much better with a good antenna and ground. So, I connected a wire
to the chassis, threw it outside, carried it with bare feet (me, not the
wire) across the wet concrete to tie it to a water faucet. As I touched it
to the water faucet, sparks flew and the lights went out.
> 8 to 10 year old boy add 50 ft bell wire, steel bar, 1 1/2 volt battery
> and some tacks. You have a electro magnet.
> next 6 volt battery = lift more tacks
> more bell wire added to coil = lift more tacks
> learned more volts + bigger coil (more wire) = stronger electro magnet
> searches garage for another battery and more bell wire but in stead
> finds about 150 ft of 14 gauge insulated wire and a 110V male plug.
> WOW a super magnet. can not wait to build this.
> put it together plug it in sparks fly and fuse blows (thank God the fuse
> did not have a penny behind it).
>
> It took out the electricity in the kitchen and 2 other rooms, this was
> 20 years ago in an old house with old wiring.
> Within a month of asking questions to people who were knowledgeable in
> electricity I knew what I had done wrong and basics of Ohms Law.
> I learned that I would always try to know what was going to happen when
> I did something. No "lets turn this and see what happens"
>
> John
>
>
>> <>
>> OK, about 45 years ago... I build the Allied Radio Knight Kit AM
>> Broadcaster transmitter (two 50C5 tubes and a 12AX7). This was one of
>> those units with no power transformer. The tube filaments were in series
>> across the line. B+ was generated using a half wave selenium rectifier.
>> One side of the line (the neutral side) was tied to the metal chassis
>> (through the on/off switch so you got a choice as to whether the chassis
>> was hot when the unit was on or when it was off). I figured this thing'd
>> get out much better with a good antenna and ground. So, I connected a
>> wire
>> to the chassis, threw it outside, carried it with bare feet (me, not the
>> wire) across the wet concrete to tie it to a water faucet. As I
>> touched it
>> to the water faucet, sparks flew and the lights went out.
>>
>> Harold
>
How many of you remember the old electric guitar amps with the 2 wire
plugs. if you did not check polarity and were holding one guitar and
someone hands you another one on a different amp. The big 60 cycle hummm.
Mario Mendes Jr. wrote:
> Virtually the same story from me, but instead of an electromagnet, I
> used a small dc motor I had ripped out of a toy =)
I tried it with a neon bulb, although I had a pretty good idea what would
happen and stood away by the fuse box.
In college we sacrificed a telephone mouthpiece in the same way. We knew it
would go poof, but it was more spectacular than I had expected. A really
nice orange flame shot out about 3 feet.
******************************************************************
Embed Inc, Littleton Massachusetts, (978) 742-9014. #1 PIC
consultant in 2004 program year. http://www.embedinc.com/products
> ....
>
> I figured this thing'd
>get out much better with a good antenna and ground. So, I connected a wire
>to the chassis, threw it outside, carried it with bare feet (me, not the
>wire) across the wet concrete to tie it to a water faucet. As I touched it
>to the water faucet, sparks flew and the lights went out.
>
>
>
Were those the house lights or your lights? 8-/ ;-)
On Thu, 2006-01-05 at 12:36 -0500, Olin Lathrop wrote:
> Mario Mendes Jr. wrote:
> > Virtually the same story from me, but instead of an electromagnet, I
> > used a small dc motor I had ripped out of a toy =)
>
> I tried it with a neon bulb, although I had a pretty good idea what would
> happen and stood away by the fuse box.
>
> In college we sacrificed a telephone mouthpiece in the same way. We knew it
> would go poof, but it was more spectacular than I had expected. A really
> nice orange flame shot out about 3 feet.
In high school, for no particular reason, we went through a phase of
"stick wires in the outlet and bridge with a piece of metal", no real
reason, we all just felt like doing it! :) Put some really nice dents in
some screwdrivers...
My favourite "electrical" thing in high school was actually not very
dangerous. Take the 0.5mm lead out of a mechanical pencil, make it about
an inch long, and then put low voltage DC through it (around 6-12V).
Glows as brightly as a light bulb, for a second or two... VERY neat! :)
TTYL
Herbert Graf <mailinglist2 <at> farcite.net> writes:
<snip>
> My favourite "electrical" thing in high school was actually not very
> dangerous. Take the 0.5mm lead out of a mechanical pencil, make it about
> an inch long, and then put low voltage DC through it (around 6-12V).
> Glows as brightly as a light bulb, for a second or two... VERY neat! :)
> TTYL
>
I used to weld small peaces of metal with this. I would take lead out of
pencil (wooden, about 1-2 mm diameter, the softer the better - more graphite)
and use it as electrode for welding. Power supply was 12V transformer, do not
remember the rating, but the heavier transformer the better.
With the mains power (220V) we used to stick 2 nails into the socket and put a
peace of paper covered with graphite from a pencil. Convenient (although
slightly dangerous) way to make fire without matches.
Another trick I used to play on my brother (he is older than me, so I am not
that cruel). He used to read long into the night and absolutely refused to
turn of his bedside lamp. When he would go out of room, I would put a peace of
moist paper into his lamp, between the bulb and central contact. The soft
paper for artwork works best. When he returned, he will switch the lamp back
on, paper will dry out in couple of minutes and the lamp will switch off!
Apparently without my interfearence! It used to drive him crazy until he
figured it out.
> Mario Mendes Jr. wrote:
> > Virtually the same story from me, but instead of an electromagnet, I
> > used a small dc motor I had ripped out of a toy =)
>
> I tried it with a neon bulb, although I had a pretty good idea what would
> happen and stood away by the fuse box.
>
> In college we sacrificed a telephone mouthpiece in the same way. We knew
it
> would go poof, but it was more spectacular than I had expected. A really
> nice orange flame shot out about 3 feet
Let´s keep adding to the list:
I opened a printer and found some SMD leds. I "touched" them with a 2xAA
battery pack I had and it turned on.
- "Wow, it lights!"
Then, I decided to use a 24V backup battery from an old house alarm...
The led made a REALLY bright flash that left a nice white spot in my vision
for about 5 minutes. Then, instantly, it burned and a string of white smoke
went up in my room.
That was how my interest in electronics got started...
Juan Cubillo
Whoever invented the toy train transformer should have a plaque dedicated to
them wherever kids get together and talk of discovery and destruction.
My big thing was to build a capacitor, charge it with the train transformer
and then watch it discharge with a spark. Years later the government taught
me how to achieve my goal.
Bill
ps. after reading this, Pookie tip toes around capacitors .
>> Virtually the same story from me,
>>but instead of an electromagnet,
>
>In college we sacrificed a telephone mouthpiece in
>the same way. We knew it would go poof, but it was
>more spectacular than I had expected. A really
>nice orange flame shot out about 3 feet.
Hadn't heard of using those, but have heard of doing it with the miniscule
3" speakers that came in the pocket transistor radios that were around in
the '60s. Never actually saw one, but the cone was reputed to fly a fair way
across the room.
> Whoever invented the toy train transformer should have a plaque dedicated to
> them wherever kids get together and talk of discovery and destruction.
>
> My big thing was to build a capacitor, charge it with the train transformer
> and then watch it discharge with a spark.
Did you ever connect it backwards, at the end of a long wire, under a
buddy's chair ?
> Years later the government taught me how to achieve my goal.
There's nothing like the smell of burning LEDs in the morning...
At my University, my friends and I were selling parts kits for the
Microelectronics 1 course. One particularly brilliant group came by,
bought their kit, and proceeded to plug their only red LED directly
into mains. They were slightly more surprised at the explosion than
they were at the revelation that we wouldn't replace the LED for free.
Unfortunately, this gave my friends and I an idea, and all the dead
equipment we can find was raided for various types of LEDs. Though we
stayed away from mains, an interesting combination of the power supply
for my PIC programmer and a pair of 9V batteries were combined to form
what we called "13.5 Volt Theatre".
We went on to find that white and blue LEDs exploded the best (clear
epoxy everywhere, and the smell doesn't dissipate for days), but that
rectangular LEDs tend to fail the most dramatically - shooting flame
and sparks out the sides for a few seconds. Most LEDs tended to get
quite bright, then quite dim, then quite smelly & broken.
What can I say - it was more fun that studying Economics :)
> Of Randy Glenn
>
> There's nothing like the smell of burning LEDs in the morning...
>
> At my University, my friends and I were selling parts kits for the
> Microelectronics 1 course. One particularly brilliant group came by,
> bought their kit, and proceeded to plug their only red LED directly
> into mains. They were slightly more surprised at the explosion than
> they were at the revelation that we wouldn't replace the LED for free.
Where I work several of the other engineers and myself were kicking around
the idea of using the inductive reactance of a capacitor to limit the
current to a bi-polar LED so we could run it directly from 120Vac. We were
all worried what would happen if the capacitor shorted and applied 120Vac
directly across the LED... So we tried 120Vac right across the LED... the
result was the emission of plastic LED fragments... We had witnessed the
birth (or re-birth) of the the PED - Projectile Emitting Diode. A distant
cousin of the DED - Dark Emitting Diode.
We just kept trying again and again - and the same darn thing happened every
time. It was a slow Friday afternoon and a lot of LEDs died a spectacular
death that day.
On 1/6/06, Mark Scoville <.....mscovilleKILLspam.....unicontrolinc.com> wrote:
> > Of Randy Glenn
> >
> > There's nothing like the smell of burning LEDs in the morning...
> >
> > At my University, my friends and I were selling parts kits for the
> > Microelectronics 1 course. One particularly brilliant group came by,
> > bought their kit, and proceeded to plug their only red LED directly
> > into mains. They were slightly more surprised at the explosion than
> > they were at the revelation that we wouldn't replace the LED for free.
>
> Where I work several of the other engineers and myself were kicking around
> the idea of using the inductive reactance of a capacitor to limit the
> current to a bi-polar LED so we could run it directly from 120Vac. We were
> all worried what would happen if the capacitor shorted and applied 120Vac
> directly across the LED... So we tried 120Vac right across the LED... the
> result was the emission of plastic LED fragments... We had witnessed the
> birth (or re-birth) of the the PED - Projectile Emitting Diode. A distant
> cousin of the DED - Dark Emitting Diode.
I'm sure you also had some NEDs there (Noise Emitting Diodes).
Bill
--
Psst... Hey, you... Buddy... Want a kitten? straycatblues.petfinder.org
> > Of Randy Glenn
> >
> > There's nothing like the smell of burning LEDs in the morning...
> >
> > At my University, my friends and I were selling parts kits for the
> > Microelectronics 1 course. One particularly brilliant group came by,
> > bought their kit, and proceeded to plug their only red LED directly
> > into mains. They were slightly more surprised at the explosion than
> > they were at the revelation that we wouldn't replace the LED for free.
>
> Where I work several of the other engineers and myself were kicking around
> the idea of using the inductive reactance of a capacitor to limit the
> current to a bi-polar LED so we could run it directly from 120Vac. We were
> all worried what would happen if the capacitor shorted and applied 120Vac
> directly across the LED... So we tried 120Vac right across the LED... the
> result was the emission of plastic LED fragments... We had witnessed the
> birth (or re-birth) of the the PED - Projectile Emitting Diode. A distant
> cousin of the DED - Dark Emitting Diode.
>
> We just kept trying again and again - and the same darn thing happened every
> time. It was a slow Friday afternoon and a lot of LEDs died a spectacular
> death that day.
>
> -- Mark
>
>
>
>> I did the "drive a nail through an Li-poly battery" "experiment"
>> the other night. Very impressive!
>
> All the lithium batteries I have, that are not in actual use,
> are kept in the fridge.
Um. that's supposed to help how? I guess the interior of a
fridge is relatively fireproof...
>
> For charging experiments, I have a chamber made of 1/4" Plexiglas.
>
The usual failure mode involves fumes and (rather violent) fire,
rather than explosion and shrapnel. I would worry that your
plexiglas would make a fine fuel for expanding the fire...
Maybe this is what I can use my old dishwasher for. Although I'm
not so sure that storing large quantities together is such a great
idea; thermal runaway is prone to jumping from one to another, I'm
led to believe...
(Li-ions are exciting. First, the electrical energy density is
pretty high. Next, the electrolyte is flammable. And finally,
some of the components (Li and Cobalt oxides?) are prone to doing
a thermite-like reaction when the temperature gets high enough.)
(these are videos from companies that market "safer" alternatives,
so they're a bit suspect. Nevertheless, they are pretty close
to the results from my own experiment (but, um, "quicker."))
>
>
> Um. that's supposed to help how? I guess the interior of a
> fridge is relatively fireproof...
That, and at lower temperatures, I'd think they are less likely to have
"accidents".
> The usual failure mode involves fumes and (rather violent) fire,
> rather than explosion and shrapnel. I would worry that your
> plexiglas would make a fine fuel for expanding the fire...
Point being to let me see what's going on, and to contain things for a few
10's of seconds till I can put the extinguisher into use.
Maybe this is what I can use my old dishwasher for. Although I'm
> not so sure that storing large quantities together is such a great
> idea; thermal runaway is prone to jumping from one to another, I'm
> led to believe...
It do in NIMH, and I'm sure Li-whatever is more delicate.
(Li-ions are exciting. First, the electrical energy density is
> pretty high. Next, the electrolyte is flammable. And finally,
> some of the components (Li and Cobalt oxides?) are prone to doing
> a thermite-like reaction when the temperature gets high enough.)
Everybody wants TONS of energy in a little bitty can. Things are likely to
get even more interesting..
I've seen a lot of fuel cells under development for laptops, but since
you'll never get one on a plane, I think the primary market is locked out.
> That, and at lower temperatures, I'd think they are less likely to
> have "accidents".
Years ago, a women's magazine "Helpful Hint" suggested that you
keep batteries in the fridge. And to keep the moisture out, wrap
them in tin-foil. No accident-waiting-to-happen there eh ? I'll bet
to this day some women think that cold air stuffs D-cells
Googled for any record of it, but came up with this instead
Jinx wrote:
>>That, and at lower temperatures, I'd think they are less likely to
>>have "accidents".
>
>
> Years ago, a women's magazine "Helpful Hint" suggested that you
> keep batteries in the fridge. And to keep the moisture out, wrap
> them in tin-foil. No accident-waiting-to-happen there eh ? I'll bet
> to this day some women think that cold air stuffs D-cells
>
> Googled for any record of it, but came up with this instead
>
> afrotechmods.com/cheap/negativeiongenerator/pikashoe7.htm
>
> > afrotechmods.com/cheap/negativeiongenerator/pikashoe7.htm
> >
>
> I like the bit where the toe was lost...
I like the bit where you choose which sensitive part of the body to
touch people on. People I think you'd have to know fairly well in
some cases. But hey, you only go around once.......
Alright I need to say something.. stupid things still get me all the time:
if(strcmp(x.str, x.str) == 0) is always true meant to be (x.str, y.str)
switch(x)
case x
....
case 10: da da da
....
case 20: do do do break
default: error msg
missing break on case 10.. hidden between all the others..
lots of other ones too, those just happened to happen today..
>
>
> Years ago, a women's magazine "Helpful Hint" suggested that you
> keep batteries in the fridge.
So far, so good, batteries and film last longer in the cool.
And to keep the moisture out, wrap them in tin-foil. No
> accident-waiting-to-happen there eh ? I'll bet to this day some women think
> that cold air stuffs D-cells
That's funny! Not just the fact that the tinfoil wouldn't do a thing for
moisture.
>
> I like the bit where you choose which sensitive part of the body to
> touch people on. People I think you'd have to know fairly well in
> some cases. But hey, you only go around once.......
>-----Original Message-----
>From: piclist-bouncesspam_OUTmit.edu [@spam@piclist-bouncesKILLspammit.edu]
>Sent: 07 January 2006 01:45
>To: Microcontroller discussion list - Public.
>Subject: Re: [EE] stupid (learning) mistakes
>
>
>> That, and at lower temperatures, I'd think they are less likely to
>> have "accidents".
>
>Years ago, a women's magazine "Helpful Hint" suggested that
>you keep batteries in the fridge. And to keep the moisture
>out, wrap them in tin-foil. No accident-waiting-to-happen
>there eh ? I'll bet to this day some women think that cold air
>stuffs D-cells
>
>Googled for any record of it, but came up with this instead
>
>http://afrotechmods.com/cheap/negativeiongenerator/pikashoe7.htm
I built a negative ion generator in my youth and had a lot of fun charging up various items. Plants with spiky leaves give off a nice blue aura in the dark, and the laves reach out and touch anyone who gets too close ;) I can remember charging up my brother who I had stand on a big pile of old polythene shopping bags to insulate him. Managed to get his hair standing on end in a classic Van De Graaf stylee when there was a huge crack and my brother lept around holding his foot. Seems old shopping bags don't have that high a breakdown voltage...
Regards
Mike
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=======================================================================
> I built a negative ion generator in my youth and had a lot of fun
> charging up various items. Plants with spiky leaves give off a
> nice blue aura in the dark
based on a car alternator (cheap from the wreckers)
Apparently sticking a few kV up a pine cone proves something
Apparently. Proves I guess that anything will give off an aura
with enough encouragement. Sheesh
I kept thinking of the Monty Python Parrot sketch all the time I
was working on it. "Mate, this bird wouldn't voom if you put four
million volts through it"
I am so tempted to get into the "unconventional beliefs" market.
There are so many unswayable people whose money I would
gladly take if it makes them happy. And there's rich pickings to
be had
>-----Original Message-----
>From: KILLspampiclist-bouncesKILLspammit.edu [RemoveMEpiclist-bouncesTakeThisOuTmit.edu]
>Sent: 09 January 2006 11:08
>To: Microcontroller discussion list - Public.
>Subject: Re: [EE] stupid (learning) mistakes
>
>
>> I built a negative ion generator in my youth and had a lot of fun
>> charging up various items. Plants with spiky leaves give off a nice
>> blue aura in the dark
>
>Ever come across Kirlian photography ?
>
>http://www.kirlian.net/
>
Yes, I looked at this some time ago. It makes some interesting photo's, but that's about it as far as I'm concerned. I just had a quick look and they are advocating eating raw vegetables due to the larger "energy field" displayed, comapred to cooked ones. Righto...you go munch on your uncooked potatoes, I'll have mine roasted, along side a few slices of mad cow and Yorkshire puddings thanks.
>A couple asked me to make a Kirlian camera
>
>http://www.kirlian.org/kirlian_camera.htm
>
>based on a car alternator (cheap from the wreckers)
>
>Apparently sticking a few kV up a pine cone proves something
>
>Apparently. Proves I guess that anything will give off an aura
>with enough encouragement. Sheesh
>
>I kept thinking of the Monty Python Parrot sketch all the time
>I was working on it. "Mate, this bird wouldn't voom if you put
>four million volts through it"
>
>I am so tempted to get into the "unconventional beliefs"
>market. There are so many unswayable people whose money I
>would gladly take if it makes them happy. And there's rich
>pickings to be had
I used to think that you'd have to have dubious morals to do this, but I figure that if they are happy to pay for this rubbish, it dosen't behove you to believe in any of it.
Regards
Mike
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> > I am so tempted to get into the "unconventional beliefs"
> I used to think that you'd have to have dubious morals to do this
I'm coming to the conclusion that I would actually be doing society
a service by starting goofygadgets.com Take the money off those
who cannot be responsible with it and give it to, well, me ;-) I'll put
it to good use
> but I figure that if they are happy to pay for this rubbish, it doesn't
> behove you to believe in any of it
That's quite true. Any retailer who actually wants to sell anything
can't judge their customers' needs. If they've got the money, I'll sell
it to 'em (stopping short at illegal substances of course). Enough
with the cotton wool, these people are grown-ups
A few months ago I was asked to make some thing called a Little
Zapper (I think). An oscillator device based on shonky 1930s
"medical opinion", that claims to cure everything. Except gullibility
I priced it at around $50 (basically a not-very-sophisticated 555
circuit). My potential customer queried why so cheap and pointed
me to a site selling a "professional model", akin to a low-performance
TENs unit, for $3000 (my estimate to build - $150). And $1500
courses on how to use it and make money. Apparently very
popular with the alternative life-stylers
>-----Original Message-----
>From: spamBeGonepiclist-bouncesspamBeGonemit.edu [TakeThisOuTpiclist-bouncesEraseMEspam_OUTmit.edu]
>Sent: 10 January 2006 07:37
>To: Microcontroller discussion list - Public.
>Subject: Re: [EE] stupid (learning) mistakes
>
>
>> > I am so tempted to get into the "unconventional beliefs"
>
>> I used to think that you'd have to have dubious morals to do this
>
>I'm coming to the conclusion that I would actually be doing
>society a service by starting goofygadgets.com Take the money
>off those who cannot be responsible with it and give it to,
>well, me ;-) I'll put it to good use
>
>> but I figure that if they are happy to pay for this rubbish, it
>> doesn't behove you to believe in any of it
>
>That's quite true. Any retailer who actually wants to sell
>anything can't judge their customers' needs. If they've got
>the money, I'll sell it to 'em (stopping short at illegal
>substances of course). Enough with the cotton wool, these
>people are grown-ups
>
>A few months ago I was asked to make some thing called a
>Little Zapper (I think). An oscillator device based on shonky
>1930s "medical opinion", that claims to cure everything.
>Except gullibility
>
>I priced it at around $50 (basically a not-very-sophisticated
>555 circuit). My potential customer queried why so cheap and
>pointed me to a site selling a "professional model", akin to a
>low-performance TENs unit, for $3000 (my estimate to build -
>$150). And $1500 courses on how to use it and make money.
>Apparently very popular with the alternative life-stylers
>
>Ka-ching ka-ching ka-ching
How wierd, I was asked to produce these exact same things in the last place I worked (as a home job). The wife of one of the quality managers (who was very scathing of the whole thing) sold them to various guilible punters. The thing is, I'm pretty sure she actualy belived they worked.
The only thing I worried about was if somehow a 9v square wave applied in the wrong place could trigger an fit or some other serious problem. Puiblic liability insurance is not cheap...
Regards
Mike
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> > > I am so tempted to get into the "unconventional beliefs"
>
> > I used to think that you'd have to have dubious morals to do this
>
> I'm coming to the conclusion that I would actually be doing society
> a service by starting goofygadgets.com Take the money off those
> who cannot be responsible with it and give it to, well, me ;-) I'll put
> it to good use.
Hey, if you want a Northern Hemisphere branch, I'm your man!
Howard wrote regarding 'Re: [EE] stupid (learning) mistakes' on Tue, Jan 10 at 13:43:
> Hey, if you want a Northern Hemisphere branch, I'm your man!
You're going to need a Northern Hemisphere Business Operator's License
in order to operate with Southern Hemisphere-derived products. The
endless piles of forms required can be too much for a single person to
navigate. Save yourself the hassle and confusion of navigating the
process, let a professional ensure that you're legally licensed to do
business in the Northern Hemisphere. My services are available for a
convenient flat rate of 150 US dollars per business name. I accept
all major credit cards, as well as Pay Pal. Upon payment, I will
begin the paperwork and send you your Certificate of License to Do
Business In The Northern Hemisphere upon completion of the process,
which usually takes a few weeks.
Jinx wrote:
>>> I am so tempted to get into the "unconventional beliefs"
>
>> I used to think that you'd have to have dubious morals to do this
>
> I'm coming to the conclusion that I would actually be doing society
> a service by starting goofygadgets.com Take the money off those
> who cannot be responsible with it and give it to, well, me ;-) I'll put
> it to good use
I'm sure Kara at this domain parking company in the UK would be happy to
sell it to you for some outrageous amount of money... or you can take
your chances and try to sign up for it some unknown time after
22-mar-2006.
(Different registrars hold on to domains for various timeframes in case
the customer was just late in paying...)
Technical Contact:
Scott, Kara adminEraseME.....dotcomnamesforsale.com
17 Essex Place
Montague Street
Brighton, Sussex BN2 1LB
United Kingdom
1273601714 Fax --
Domain servers in listed order:
PARK7.SECURESERVER.NET
PARK8.SECURESERVER.NET
I built a very straight 12V stabilized power supply, planned with 7812.
Afterwards, I changed my mind and put a pin-compatible LM2940-12 which is
a low-drop version of 7812. And it began to oscillate. Do you guess, why?
The data sheet of the LM2940 tells to put definitely a 22uF capacitor
paralel to the output. It is not required on the 7812. I learned again to
read the data sheet even if the info seems to be
unimportant/known/superfluous.
Yeah, it was oscillating because of an incorrect ESR in your capacitors.
The LM series LDO regulators from National are *extremely* interesting
devices. I'll leave the long version of the story out and just say that you
need to be careful when designing your circuit with those. If either of
your capacitors fails, you will see *massive* voltage spikes on the outpout
as a result. I can't remember which does what now, but the input cap is
there for voltage regulation and the output cap is there for cycle
regulation (or vice versa, don't remember exactly, but you get he gist). So
if one of them breaks down because say it's rated for 16V and it
occasionally getting 25V spikes, then you will eventually be sending 40V
spikes in to your uC circuit. Found this little nugget after reverse
engineering a previous years Senior Design project.
>
> Here is my story,
>
> I built a very straight 12V stabilized power supply, planned with 7812.
> Afterwards, I changed my mind and put a pin-compatible LM2940-12 which is
> a low-drop version of 7812. And it began to oscillate. Do you guess, why?
>
> The data sheet of the LM2940 tells to put definitely a 22uF capacitor
> paralel to the output. It is not required on the 7812. I learned again to
> read the data sheet even if the info seems to be
> unimportant/known/superfluous.
>
> Regards, and happy new year
> Imre
>
> Yeah, it was oscillating because of an incorrect ESR in your capacitors.
> The LM series LDO regulators from National are *extremely* interesting
> devices. I'll leave the long version of the story out and just say that you
> need to be careful when designing your circuit with those. If either of
> your capacitors fails, you will see *massive* voltage spikes on the outpout
> as a result. I can't remember which does what now, but the input cap is
> there for voltage regulation and the output cap is there for cycle
> regulation (or vice versa, don't remember exactly, but you get he gist). So
> if one of them breaks down because say it's rated for 16V and it
> occasionally getting 25V spikes, then you will eventually be sending 40V
> spikes in to your uC circuit. Found this little nugget after reverse
> engineering a previous years Senior Design project.
Wow, neat one, that. I infer that the only way to make it work with
'any' capacitor is to use 22uF in series with 0.22 Ohms at the output,
to ground, and a voltage clamping device (5.6V zener probably) after it,
as well as a fuse. Nice part. Hmm.
embedinc.com>
