Dumb / Fun electrical stuff you did as a kid.

[akcoder]

I also discovered 2 years ago the wrong way that Honda was kind enough to put a crowbar circuit in. I was putting the charger on the battery, and in my frustration and haste swapped and leads. I heard a bang and then crapped my pants :-) I tried the ignition and nothing came on. I thought for sure I had smoked the ECU. A few minutes later I discovered it was just a $7 100 amp fuse, thankfully!

-dan

[akcoder]

daddy longlegs and huntsman are not the same, at least in australia anyway. Huntsman are really nice spiders. They wander around your house and eat the other bugs.

I meant to say a harvestman spider, which us yanks call daddy long legs. I have no issues with spiders now (or even then), I'm trying to teach my kids (5 and 3) not to squish them, and teach them that spiders eat the "yucky" bugs.

-dan

[gxti]

When I was roughly 12, for some inexplicable reason I tapped the exposed contacts of a 240V well pump relay with a hammer. Dimmed the lights and took a 1mm chunk out of the hammer's face.

[cwalex]

daddy longlegs and huntsman are not the same, at least in australia anyway. Huntsman are really nice spiders. They wander around your house and eat the other bugs.

I meant to say a harvestman spider, which us yanks call daddy long legs. I have no issues with spiders now (or even then), I'm trying to teach my kids (5 and 3) not to squish them, and teach them that spiders eat the "yucky" bugs.

-dan

Sorry for the off topic

The huntsman spiders are the ones that can get really big. I don't know if they are common in other countries. When I lived in a house in the middle of 4 acres of bushland we used to get them in the house all the time. They are just lost, they come in the house but they are supposed to live in the bush. They look scary due to the size but they are harmless. I used to have fun chasing them around the house to catch them, the other house occupants would just kill them if they saw them so I made it a priority to get them out of the house

My most disappointing relocation was when I put one out the back yard and immediately a magpie swooped down and grabbed it in one swift motion. Oh well that is life and at least the magpie was eating it's usual diet instead of being fed bread scraps and such. My stepdad keeps a birdbath full of dry dogfood to feed the magpies. They bring their babies with them too. They get really tame and will take food from your hand. We had some kookaburras that would come in for a feed and would let you touch and stroke their feathers. Birds are another animal that I love to watch and sometimes interact with when they  let me

[Mechatrommer]

1) i tried to fix a fan's broken live wire by connecting them with bare hand, pzzzsst.
2) same thing i disconnected a ceiling fan's condenser (fully charged capacitor) and bring it with hand having learnt from (1) that anything disconnected from mains should be safe, pzzzzsst.
3) i stole a friends ringing bell desk clock and transform it into stepped down geared electric car.

[akcoder]

Birds are another animal that I love to watch and sometimes interact with when they  let me

Birds, grr :-) Going way off topic, I spent all summer cleaning bird crap off my car doors, wondering why it was always in the same spot. Turns out, the magpies would swoop down, sit on the window sill and peck at their reflection in the side view mirrors. I decided to turn in my mirrors when I got home from then on out

-dan

[westfw]

carton of eggs in the microwave

Young'n's!  I assume this has very similar results to putting some eggs on the (regular) stove to hard boil, and then going out shopping for a couple of hours?

Relatively embarrassingly recently, I decided to chop the cord (for future use) off some appliance with a knife, after confirming that it was bad by plugging it in and trying it out.  It would have been better if the cord that I had carefully unplugged had been the one on the bad device, and not some other random appliance in the same outlet.   It ruined one of my favorite knives!

[vk6zgo]

I was relatively safety conscious as a kid,but I did one seriously dumb thing after I started work!

We had some old tube type "Radiogram" chassis left over from when we used to sell the made up units.
The Boss decided to sell them off cheap,& I was given the job of testing them.

I looked everywhere,trying to find the speaker connection,finally finding a "figure 8" lead coming out through a grommet in the chassis.
I connected this up to a 12" speaker & turned on the radio.

There was a sound like a rifle shot,& the mains fuse blew.
It turns out that the "fig 8" was switched 240V to the record player unit!

[TerraHertz]

carton of eggs in the microwave

Young'n's!  I assume this has very similar results to putting some eggs on the (regular) stove to hard boil, and then going out shopping for a couple of hours?

Um, no. You've heard of flash-boil steam explosions?
Well an uncooked egg is mostly water. In a water-tight container that is pretty strong due to its shape. So in the microwave oven the eggs just sit there, getting hotter and hotter. They get to over the boiling point of water, with the pressure going up and up and still they don't explode. Then one of them does. This detonates all the others.
Of course the contents are not pure water. The oven gets exploded, and the 'omlette' spray is pretty uniform on the surrounding area.


My favorite microwave oven trick is the free-floating plasma 'flame'. It's a very interesting sight, a great tutorial in high power RF behavior, and mostly harmless to the oven. Mostly...
There are several ways to achieve it, though all can be finicky. The easiest:
Take a standard wooden matchstick. Light it. Let it carbonize about half the matchstick then blow it out. Now you have a bit of wood with an attached piece of delicate charcoal, full of micro-cracks.
With a bit of wax, bluetack or whatever, carefully stick the wood base of the matchstick to a stable base, that can be placed in the microwave. Best if it's on the rotating plate, so it travels through different zones of the field standing wave. The match should be upright, charcoal end up.
Close the oven, set to full power, turn on.

If it works, you'll see a plasma flame appear at the match, then separate and drift around in the oven, following a complex and pretty random path influenced by multiple factors. Including the movement of the maximum RF standing wave field nodes and convection of the air heated by the plasma. If it's an old transformer and half-wave rectified HV type of oven the 'flame' buzzes loudly at 50Hz, because the RF field is pulse modulated at mains frequency. Effectively you're looking at a crude flame audio transducer.

The 'flame' wants to convect upwards with the heated air, but its energy source is the microwave standing node, which is moving unrelated to the air. Also the flame itself is conductive and absorbing field energy, therefore altering the geometry of the standing wave. It's quite a chaotic system, so can be very variable. If the plasma flame gets detached from its RF node, it just goes out instantly. And can't restart.

It's interesting to consider what happens at the initiation of the flame by the matchstick. It happens too fast to follow, and afterwards the matchstick is gone. I'm guessing the charcoal has small cracks in the moderately conductive carbon. The carbon length acts as an antenna, focusing RF energy across the cracks. So an air breakdown arc starts there. But the arc itself is a conductor, and can absorb energy from the field. It does - vaporizing the carbon and getting bigger. It rapidly destroys the matchstick, and grows to the maximum size supportable by the energy being input to the RF field by the magnetron. At this point it is no longer anchored to anything physical, so it is free to drift off. It then follows the most energy-rich path in the RF field.

I said it's 'mostly harmless' to the oven, because the arc is just a load, no different to a glass of water. BUT... the floating arc can end up parked against the oven wall at some point. Where it will burn the paint, or maybe even burn through the metal. That's not desirable since then you'd have a major RF power leakage, which is dangerous to you.

I've seen some people claim this process is 'ball lightning'. But it most definitely isn't related at all.
However it's still fascinating.

The matchstick method only works once per match. Another method I found would work repeatedly, involved a small ring of graphite (it was a shaft seal in a liquids pump) with a slot cut in it. Much like the loop antenna and airgap used in the very first demonstration of radio wave transmission, but much smaller. I set the ring in a ceramic holder, gap facing upwards, put in oven. A plasma flame would reliably form at the ring's gap then break away and float around freely. As soon as it extinguished another would start at the ring gap. I presume this behavior was due to the floating arc absorbing enough of the RF energy to bring the field strength low enough so no new arc could form at the ring's gap. Extinguish the floating arc, field strength goes up, new arc forms, cycle repeats.
Unfortunately the little graphite ring eroded away and stopped working, and I only had one such bearing, salvaged from a pump I'd found.

[Psi]

When i was young i mounted two terminal bolts into the side of a 2L coke bottle with a washer on each side and silicon (to make it airtight).
Then i connected the terminals up to the output of a car ignition transformer.

Then a cup of water and a teaspoon of calcium carbide went into the bottle and i capped it tight.
After the coke bottle had swelled up and the sides were bulging quite a bit i hit the button on the ignition transformer circuit.

Well..

You know what a dry ice bomb sounds like, this was worse, much much worse. (or much better, depending on your point of view).

It exploded with a blinding flash and a bang that could only be described as "the end of the world".
Neighbors from all sides were running around trying to figure out what had happened. hehe.

[steve30]

Can't think of anything particularly bad.

I did recently connect an overhead projector transformer's secondary winding to the mains. Not remotely spectacular. But a few years earlier, the OHP itself did fall out of the loft hatch , and the glass stage hit the corner of the step ladder causing shattered glass to go all over the place. Fortunately I caught it before it fell down the stairs .

At college a few years ago, we stayed behind one day with the technician, and put some capacitors in coke bottles and blew them up by connecting them the wrong way round to a bench PSU. That was cool.

[cwalex]

carton of eggs in the microwave

Young'n's!  I assume this has very similar results to putting some eggs on the (regular) stove to hard boil, and then going out shopping for a couple of hours?

Um, no. You've heard of flash-boil steam explosions?
Well an uncooked egg is mostly water. In a water-tight container that is pretty strong due to its shape. So in the microwave oven the eggs just sit there, getting hotter and hotter. They get to over the boiling point of water, with the pressure going up and up and still they don't explode. Then one of them does. This detonates all the others.
Of course the contents are not pure water. The oven gets exploded, and the 'omlette' spray is pretty uniform on the surrounding area.


My favorite microwave oven trick is the free-floating plasma 'flame'. It's a very interesting sight, a great tutorial in high power RF behavior, and mostly harmless to the oven. Mostly...
There are several ways to achieve it, though all can be finicky. The easiest:
Take a standard wooden matchstick. Light it. Let it carbonize about half the matchstick then blow it out. Now you have a bit of wood with an attached piece of delicate charcoal, full of micro-cracks.
With a bit of wax, bluetack or whatever, carefully stick the wood base of the matchstick to a stable base, that can be placed in the microwave. Best if it's on the rotating plate, so it travels through different zones of the field standing wave. The match should be upright, charcoal end up.
Close the oven, set to full power, turn on.

If it works, you'll see a plasma flame appear at the match, then separate and drift around in the oven, following a complex and pretty random path influenced by multiple factors. Including the movement of the maximum RF standing wave field nodes and convection of the air heated by the plasma. If it's an old transformer and half-wave rectified HV type of oven the 'flame' buzzes loudly at 50Hz, because the RF field is pulse modulated at mains frequency. Effectively you're looking at a crude flame audio transducer.

The 'flame' wants to convect upwards with the heated air, but its energy source is the microwave standing node, which is moving unrelated to the air. Also the flame itself is conductive and absorbing field energy, therefore altering the geometry of the standing wave. It's quite a chaotic system, so can be very variable. If the plasma flame gets detached from its RF node, it just goes out instantly. And can't restart.

It's interesting to consider what happens at the initiation of the flame by the matchstick. It happens too fast to follow, and afterwards the matchstick is gone. I'm guessing the charcoal has small cracks in the moderately conductive carbon. The carbon length acts as an antenna, focusing RF energy across the cracks. So an air breakdown arc starts there. But the arc itself is a conductor, and can absorb energy from the field. It does - vaporizing the carbon and getting bigger. It rapidly destroys the matchstick, and grows to the maximum size supportable by the energy being input to the RF field by the magnetron. At this point it is no longer anchored to anything physical, so it is free to drift off. It then follows the most energy-rich path in the RF field.

I said it's 'mostly harmless' to the oven, because the arc is just a load, no different to a glass of water. BUT... the floating arc can end up parked against the oven wall at some point. Where it will burn the paint, or maybe even burn through the metal. That's not desirable since then you'd have a major RF power leakage, which is dangerous to you.

I've seen some people claim this process is 'ball lightning'. But it most definitely isn't related at all.
However it's still fascinating.

The matchstick method only works once per match. Another method I found would work repeatedly, involved a small ring of graphite (it was a shaft seal in a liquids pump) with a slot cut in it. Much like the loop antenna and airgap used in the very first demonstration of radio wave transmission, but much smaller. I set the ring in a ceramic holder, gap facing upwards, put in oven. A plasma flame would reliably form at the ring's gap then break away and float around freely. As soon as it extinguished another would start at the ring gap. I presume this behavior was due to the floating arc absorbing enough of the RF energy to bring the field strength low enough so no new arc could form at the ring's gap. Extinguish the floating arc, field strength goes up, new arc forms, cycle repeats.
Unfortunately the little graphite ring eroded away and stopped working, and I only had one such bearing, salvaged from a pump I'd found.

like this?

[johnwa]

Heard somewhere that if you connect a fluorescent lap starter to an incandescent lightbulb, you get blinking light. Tried that, but for whavever reason I connected the starter in parallel with the bulb... boom. Connected the second one in series and it worked.

Now there is a clever idea! I just tried that, it works! (in series). I wonder if the starter will survive continuous operation?

The microwave oven is an unresistible device.

I agree, a while ago I picked one up at the tip for the express purpose of 'cooking' non-food things. An interesting (although not particularly spectacular) thing to try is some black iron oxide, as used for colouring tile grout. It will go up to yellow heat, and appears to be reduced to metallic iron.

[digsys]

Back when fireworks were legal here, and I started making my own, I was fascinated by double bangers.
My new design was more a mortar - I made 6 launchers, bolted to my front wheel forks - had 6 switches on the handle-bars,
and powered by the light generator. I'd roam the streets launching smoke / stink / flash / etc "grenades" at anyone who
dared be in front of me :-)  I was soooo cool.
One day there was a church fair next to a friends house. It was a very large property and the shared fence was quite high.
I made up the biggest mortar I'd ever attempted. He had grapes, so I gathered hundreds of caterpillars and loaded them into
the det chamber - remote trigger naturally.
It was an awesome success !! They exploded way above all the food and trading stalls - shredded caterpillars rained all over.
What I didn't count on was the sheer panic / screaming / stampede that followed - there was no exit plan at this age.
I bolted out of there and laid low for a week, didn't even dare to watch TV or listen to the news. Man, I was sh***ing myself !!

[AlfBaz]

When I was really young (about 7yo) my parents had one of those old bed heads that had like a book shelf in it with a light bulb either end. One of the lights bulbs was missing and I could see the 2 spring loaded prongs and decided to push them with my finger... I was doing this under the lighting provided by the light bulb on the other side... OUCH.

Later that day I told my Mum about it and that apart from the body buzzing my finger felt hot and that I was going to try it again but wet my finger so that it wouldn't burn. Thank god for Parents!!

A little older now, 11 or 12, heading home with a couple of friends from the bush up the road. One of my mates had found a length of 3/4" water pipe which we had been playing with. Just up the road from our houses a bright idea entered my head. I borrowed the pipe from my friend and suggested we may see some sparks if we through it up at the power lines.

"What a great idea!!" they all said.

I swung the the pipe upward holding it from one end. It turned end over end, and  in what seemed like slow motion it followed a beautiful parabolic arc, up and over the power lines landing perfectly perpendicular to two of the conductors.

The massive arcs/sparks it produced looked exactly like the pattern iron filings make when sprinkled on paper over a bar magnet, and the sound....
It stopped when one of the lines melted through. As this was close to one of the power poles the long length of power line fell to the road, landing in the gutter just in front of me.

We all stood there frozen, completely in shock, staring at each other, a shade of white I will never forget.

"Psst, Psst", I heard. I turned around and a man from the house in front of where it happened said "Quick quick, piss off home". No arguments or words exchanged, we ran home.

Shortly after the electrical truck arrived and spliced the cable, the join is still there today! I remember when they remade the air brake switches nearly across from my parents, there was a pretty big arc when they made contact. The guy said "Jesus, must be a lot of stoves on". Well it was around tea time.

The police went knocking door to door. When they got to my parents place, they were out, the officer said does xxx live hear. I fessed up immediately, telling him exactly what happened. He said that I may be asked to visit the local police station for a stern talking to by his boss, but I never heard from them again.

He must of seen the complete look of fear in me and just left it at that.

Who would of thought I would follow up in an electrical career

[AndyC_772]

I feel like I lived a safe, deprived childhood, learning mainly from reading then trying, rather than trying then cleaning.

Experience is learning from one's mistakes. Wisdom is learning from other peoples'.

[TerraHertz]

like this? <youtube vid>

Ha ha ha... no, without the histrionics,  wussy 'contain it in a glass', and dumb surprise that a kilowatt plasma flame might crack a glass. Not like that at all!
It's much more fun to pick up an old street toss microwave oven, fix whatever simple thing is wrong with it, then use it without a care for damaging it. Dust to dust, broken to broken... 

Also, he didn't have to burn the match in the oven. It barely started, because he didn't get enough length of charcoal match stick to work well as an antenna.

[JuiceKing]

Shorting car batteries connected in series was incredibly foolhardy.

Playing with spark gaps generated by a photocopier transformer connected to mains was pretty dumb.

Confining mixtures of powderized potassium permanganate and glycerine to small glass bottles is another.

I could go on.

We lived a charmed existence.

[Stonent]

When i was young i mounted two terminal bolts into the side of a 2L coke bottle with a washer on each side and silicon (to make it airtight).
Then i connected the terminals up to the output of a car ignition transformer.

Then a cup of water and a teaspoon of calcium carbide went into the bottle and i capped it tight.
After the coke bottle had swelled up and the sides were bulging quite a bit i hit the button on the ignition transformer circuit.

Well..

You know what a dry ice bomb sounds like, this was worse, much much worse. (or much better, depending on your point of view).

It exploded with a blinding flash and a bang that could only be described as "the end of the world".
Neighbors from all sides were running around trying to figure out what had happened. hehe.

Acetylene bomb?

I remember one particular 4th of July on the lake near my Uncle's house, people were filling trash bags with acetylene and lighting them.

I took a coke bottle before and filled it with salt water about 3/4 of the way and stuck carbon electrodes in an glued them air tight and let it run off a battery charger for about 10 minutes. I poked another hole and lit it. It sounded like a gun firing and fortunately the bottle didn't explode in my face.

[Kremmen]

When i was a teenager the world was a different place. For example potassium chlorate was freely available in the form of a popular brand of weed killer. Our secret basement chemistry lab was in full swing producing rockets and bombs using sugar and powdered aluminium as fuel and p. chlorate as the oxidizer. The only drawback to this mix was the intense persisting white smoke produced by the combustion. That provided too easy beacons for the local police to locate our launch sites. Nevertheless we never got caught. The dumb part wasn't that we did it because even then we knew what we were messing with. We always used electric ignition using pieces or resistor wire from a stove plate, long cables and motorcycle batteries. The dumb part happened when we prepared to detonate our magnum opus, a bomb with some 2.5 kilos of the mix. This was in a reinforced container to ensure pressure development, but for the same reason we didn't want to blow it under free sky due to risk of shrapnel. Luckily the suburbs of Helsinki were and are riddled with old WW 1 era fortifications with gun emplacements and bunkers. All the doors have been blown away to discourage squatters so there was free entry into the bunkers. We stuffed the bomb into a convenient ventilation shaft in the wall of one, clambered on the roof and started ignition sequence. It didn't cross anyone's mind to think exactly where said ventilations shaft would emerge. When the bomb went off it became quite evident though, as not a meter behing our asses compacted debris from the shaft shot into low orbit, accompanied with a huge boom and a cloud of white smoke the density of foam rubber. Again we ran rather fast.
Later we did a few tests with a mortar system for a rocket first stage, using a tram axle as barrel and shotgun charges as drivers. We stopped that quickly after the test firings because the solid steel test "vehicles" achieved peak altitudes of roughly a kilometer or more, comparable to a standard 81mm light mortar. You could just see the day-glo orange projectile on and off in zenith as it tumbled in bright sunlight. None of the small number of test projectiles were ever recovered even when we dug into the re-entry craters more than a meter and a half. Decided that it wasn't worth it since causing real damage to life or property was just a matter of time. But it sure was fun. Nowadays of course they would lock you up and throw away the key for something like that.

[Stonent]

I've always wanted to play with this stuff.

[Psi]

Acetylene bomb?

I remember one particular 4th of July on the lake near my Uncle's house, people were filling trash bags with acetylene and lighting them.

I took a coke bottle before and filled it with salt water about 3/4 of the way and stuck carbon electrodes in an glued them air tight and let it run off a battery charger for about 10 minutes. I poked another hole and lit it. It sounded like a gun firing and fortunately the bottle didn't explode in my face.

yeah, acetylene bomb.

I tried it again a few times a year later, well away from houses/people. I set it up on a empty beach but i could never get it to explode like that again. I think it was just a pure fluke that the gases was at perfect explosive levels and under extreme pressure when i hit the button.

[MetraCollector]

I started with electronics too late

I built this when I was 17:

[smashedProton]

I'm still a kid...   
But a year ago, I made a coilgun from a large 300 v DC bus capacitor. 
I had a really fun time shooting chunks of iron out of my window and onto the steet!
Also, I made a high voltage flyback driver from junkbox parts.  I was even able to reuse the project in my psuedo-science class
by claiming that i made the model just for the class, and that it is a model of the chemical and electrical synapses of neurons!

[peter.mitchell]

All the talk of microwaving stuff seemed so interesting, so this morning i went the cheap shop and bought a $25 microwave, the first and last thing i microwaved was a full beer bottle.