ok here it goes....i thought about sharing this story about what i done during a boring physics lesson at school, it sounds quite dangerous, but luckily i am still alive to tell your guyz out there.
I was bored during class when the teacher was explaining facts about an electric socket. The teacher told us many facts about an electrical socket that gives an output of 240 volts and 0.5 amps. And then he said that 0.1 amp can kill someone. Without realizing or caring about what he said, i was dared by my friends to shove a pair of scissors into the socket and turn it on. Once i did it, the whole classroom lights suddenly blew out, and all electrical appliances that run on mains switched off. Sparks then came out of the socket holes and I was laughing.
Luckilly the teacher didnt see me or anyone else appart from my friends. After the physics lesson, everyone said that the whole of the 4th floor had a blackout. And dats the point where i laughed hard
I still dont know why i did that in the first place, although i know it was a stupid thing to do and i could have got myself killed. But all i really know is that i blew up many fuse,
it's described at walking on the edge of committing a darvin
Well, I'm not sure if your teacher is mistaken or you've just remembered it wrongly, but a 0.5A on a 240V is not sufficient to power many things. E.g., the total power of a 240V 0.5A is 120W, that's slightly higher than an old fashion 100W lightbulb. The max plug in UK (which I believe is so in HK) is 13A, that is more than 3000W, which then can be used to power stuff like an iron/heater, which goes around 2000W.
Pluging in the scissors to the socket short circuit it and hence creating a flux high current, blowing/triggering any safety fuse along the way. Since you said the entire floor was blackout, it seems that it only blown/triggered 1 major fuse. Unlikely it will cause multiple blown/triggered fuses.
On the 0.1A killing a person issue, if you consider a person's resistance is 2MOhm (which I think is higher than that), it would take a relatively large 20MV (that is 2x10^7) voltage across, which you can't easily get (if not impossible, consider a high tension cable is probably around 1MV). If you were to get that kind of voltage, the power across would be 0.1x0.1x2MOhm = 20,000W, which would definitely kill someone. Consider the amount shown, I bet it takes less than 0.1A to kill someone. To put into perspective, a Taser gun has a peak (not constant) voltage of 50,000V, which is (consider the 2MOhm assumption) 0.025A.
FYI, in most cases of electric shock cases, the fatal part is usually the duration of the electric shock (i.e. small continuous current flowing, cooking you for 30 minutes) or hurting yourself after a shock (i.e. knock yourself onto the solid ground after a shock).
Anyone fall asleep yet? anyway, whatever you do, don't mess with electricity. Respect it.
p/s: Sorry for the lengthy lecture above.. "occupation sickness".
Alan Chan said:
I still dont know why i did that in the first place, although i know it was a stupid thing to do and i could have got myself killed. But all i really know is that i blew up many fuse,
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You might want to lay off the pipe. As you can see, there is no good that can come from it.
16 Volts AC straight through the heart can be fatal.
AC requires about 60 mA to cause fibrillation, DC needs 500 mA for the same result. Fibrillation is not always fatal....
get new friends
mikechannon said:
Jees it'll be a merciful release.
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I have a heart condition and I can assure you from personal experience that fibrillations are far from mercyful
wow, i never knew you guys would be so passionate about what i did. I thought u guyz would growl at me for my stupidity.
Hanmin, you can be my next physics teacher for giving me a very comprehensive lecture , your lecture was easilly understood compared to my crappy science teacher
and yes ultraprimeomega, i think i may need new friends for the sake of my safety and education
Anyone here watching "Myth busters"?
They did a whole episode on throwing electric appliances in to bathtub and measuring the current across the "heart" of a dummy to see if dropping a hairdryer or toaster in the bath can really kill you.
I didn't see that Mythbuster. I guess it should be confirmed? Although there are lost of circumstances influencing the outcome:
-use pure H2O, it hardly conducts
-use non-ionic bath oil (good for the skin too)
-a decent Residual-current device would cut off power before you can even notice it
-a decent low amp fast fuse could be a life saver
-high ionic bath salt makes the water much more conductive than your body
-place the tub on rubber, use PVC water supply and drain pipes
they had to mess with the fuses to get enough current to kill the gel doll before they went off
Rudegar said:
they had to mess with the fuses to get enough current to kill the gel doll before they went off
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oh, right, a gel doll again... very nice material for ballistics, although I believe they should put bones in it for realistic results.
Arteries, veins and nerves are full of ions giving excellent conductive paths through our body, I doubt if they simulated those in the gel.
I got kicked out of woodwork when i was 13 for tying a pupils tie round a lathe and threatening to turn it on, because he had made a better baseball bat than me, unfortunatly, for him, my friend hit the power button and nearly killed him, we promptly got suspended and moved into sewing as a punishment, with a teacher from hell. My friend who i wont name decided to wire up some gold thread to the mains socket and complained to her(teacher) that the machine was faulty, needless to say when she touched the machine she was electrocuted along with my friend, who was promptly expelled, and i was giving a severe caning, in those days we had no trip switches so the only thing that saved them both was the thin gold thread that blew as well.
Moral of the story is dont mess with electrics, or hang around with nutcases
Maggy said:
oh, right, a gel doll again... very nice material for ballistics, although I believe they should put bones in it for realistic results.
Arteries, veins and nerves are full of ions giving excellent conductive paths through our body, I doubt if they simulated those in the gel.
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With an heavy insulation on the outer body part (i.e. skin = not very good conductor), not even a gold wire inside the body matters. Further, I suspect that the water and the bathtub plays an important part as well.
First, consider that you throwing an electrical appliance into the water, chances are, the 'Neutral' line will be in the water (together with the dangerous 'Live'). Any current from the live line will eventually find the shortest path to the neutral line, leaving the rest (i.e. probably you) untouched.
Then, consider that the current is increased, hence requiring not only the shortest path to the neutral, but a lot of paths to the neutral as well. As with the Faraday cage theory, electric current will tend to go around an object (i.e. electrons repelling each other), especially a better conducting one (i.e. a car protecting the driver from a lighting strike). As such, in terms of choice, if the current require additional path to go to the neutral, chances are, it will rather go via the water (better conductor, I think) or the steel bath tub (i.e. like the body of a car), than your body.
Hanmin, your whole story sounds fair enough... for laymen.
First of all you're mixing up AC, DC and static behaviour.
Faraday created spectacular shows using extremely high static charges, indeed comparable to a car hit by lightning. If you want to conduct an experiment with a metal bath tub filled with nice warm water and any bath soap, salt or oil struck from the side by lightning, I volunteer to step in.
So, our PC's have metal housing, you'd say, so they're a Faraday cage? Right? Wrong. I've had a computer company near the Dutch coast where thunder and lightning are regular events. I could tell when repairs would come in the next day. Phone, Lan and power wires go straight into the metal cage without making contact with the cage itself. Lightning doesn't even have to strike these wires directly, induction can be fatal for your equipment.
Edison called AC "the killer current" and refused to sell AC. AC can not "flow away" to neutral, it wants to go to earth/ground. As long as the fuse doesn't blow, it delivers as much energy as it can. In a bath tub it will not behave like lightning trying to find the shortest way, but like a cloud, spearding as fast as it can. Remember electrons all have the same negative load so they push each other away. And they are LIGHTning fast.
That's why it's also not a good idea to use a standard vacuum cleaner to clean your PC on the inside: the motor will create a cloud of electrons trying to find a way to ground. The free electrons can move much faster through the cloud of static charged dust particles toward your PCB than the slow air stream moves to the vacuum.
The surface of the dry skin is indeed a bad conductor. But even good enough for ECG using leads with suction cups or stickers. And ECG measures very faint electrical pulses in the heart, even with leads on the hands or feet.
Most people believe that water is a good conductor. But in fact pure water is an almost perfect isolator. And even tap water in most Western societies is so pure that you can hardly split it into hydrogen and oxigen using a fairly safe 12 V DC set up, not without first adding a hand full of salt. Current needs ions to move through a liquid, our bodies are full of ions, tap water has much less.
Niiccceee.. good that my explaination has someone to read it in details. I'm so worried that my stuff will get everyone to sleep. Anyway...
You are right that the induction from a lighting can toast your phone, lan and power line. However, as these lines are not long and straight enough anywhere near the PC, the fatal induction is actually caused by somewhere along the way to your company (e.g. from the phone exchange, along the telephone pole/underground, to your company). Your PC will be safe from lightling if it is disconnection from possible external induction source (e.g. the phone line to the outside world). I'm happy to put myself inside the PC case (if it is big enough) for a lighting strike
Some history lesson for all. Edison called the AC the killer current mainly because of the business competition between the DC and AC business. As Edison has spent a lot of money and effort just to change the public point of view on the safety of electricity, and just as the business is getting some money... this Tesla (I think) guy made AC electricity and business is good (costrofit ratio), due to the fact that AC has a certain edge on long distance transfer (I'll omit the details on this). Hence, Edison is trying very very hard to make AC look dangerous, by killing innocent animals (in some cases, virtually just cook it), and eventually, co-invented the electric chair.
In the view of the danger of DC current, it is a false impression of most people thinking that DC current is safe, mainly because the DC current we normally exposed to are low voltage DC current (e.g. batteries and phone charger). However, in strict AC/DC defination, a lighting strike is a DC current. And, I think a Taser gun uses DC too (you would certainly need to use some form of capasitor to store enough voltage for a shock, using regular batteries), unless the battery use is exceptionally designed for it.
Anyone has a Taser to confirm this? Does it gives out a buzzing sound from low to high frequency when armed some AA batteries operated cameras with powerful flash will have the same buzzing noise, indicating that the capacitor is charging, ready for the flash).
As for your statement of "AC can not 'flow away' to neutral, it wants to go to
earth/ground.", I'm not sure if you really meant "can not", or "not only". Anyway, all AC electric stuff, electrons goes between live/neutral, and does not require the earth/ground to be functional (not safely, at least).
If you remember some electric circuit theory, if caes where you have two parallel line (AC or DC), with one line much lower resistance (i.e. shorter distance between live and neutral) compared to the other (longer distance to 'ground' where 'ground' is not designed to pair with live), majority of the current will go through the lower resistance route and hence current that goes through the high resistance route maybe very well harmless. HOWEVER, there are cases where the current in through the high resistance route is harmful, that are in the cases where the current going through the low resistance route is excessive high. Example, the low:high resistance current ratio may be 100:1. If it takes (say) 1A to be fatal, the other route will need to have 100A (which will have all fuses nuked - e.g. my house has a main fuse of about 80A for both the heater and the cooker). That's what mentioned on my post above around the "consider that the current is increased..." section. And, as for the case with extreme high current, apply the Faraday thing mentioned on your first paragraph.
Take the Taser gun for example. If you were read the user manual, there is a minimal distance requirement between you and the target, due the the fact that the probes triangular trajectory path. Being too close to the target, will cause the probes to be too closely attached, not giving enough muscle area to 'disable' the target. The electron will not spread around (like clouds) through all the muscle, just the shortest route to the other probe (there may be current through other muscles, but too small to be noticeable).
Where in the Western societies are you in now? US? Nice... in the UK, you are/not so lucky, as you dont get very much pure water over the tap. UK is on hardwater, which seemingly adding mineral to the diet, probably in such situation, protect us from electrocution? If you were to be 1+ hours around London, take a bit of tap water, leave it on any surface and leave it for it to evaporate. At the end of the day, you'll get a pile of white powder. Yes, it is this bad.
As for the ECG issue, it goes the same with the low-vs-high resistance route. I'm sure it wont work underwater (dirty water?). However, still, it is a better conductor than many things.
Taser guns use electronics related to those modern tiny switched power adapters. The result in both cases is indeed DC. The physics of the lightning path are very complex, lightning can fork out to lots of places being hit by one strike but in general you're right that DC/static tries to find a short route.
In one of my first messages in this thread I mentioned what DC it takes to kill, so yes, I'm well aware that there is no such thing as "safe electricity".
If you short a capacitor or battery, current flows in one direction, from high potential to low potential till both potentials are equal.
AC doesn't come in batteries or capacitors, it comes from a generator constantly pulling the potential from above neutral to below neutral, 50 or 60 times a second. If you would short circuit the generator itself it would continue to produce electricity as long as it hasn't killed itself. There is no flowing away till both potentials are equal.
I'm a retired computer engineer, but I still do remember Ohm's law, thank you.
In case of the bath tub it means:
we have a fixed voltage (U) of 110 or 220V, depends where you live
we can measure resistance (I) from the device that drops into the water to the feet of the tub, to the tap, to the drain
U=I.R in this case U=I1.R1+I2.R2...InRn
With an 80A fuse, the radio falling on the feet, the tap behind the back and the drain and two tub feet straight under it it seems likely that about 2/3 of 80A, well lets say 50A will strike you, 50 x 110 = 5500W
That should boil the egg if not electrocute it
I WOULD SAY YOU WOULD GET A GREAT SHOCK FROM A TOASTER IN A BATH. If you took a mains plug and put two springs on the live and neutral and inserted this into a bath of water it would generate heat, i know i have boiled a cup of water for tea by this method. so if the electricity didnt kill you you will be boiled like an egg
yeah in some situations i see myth busters as more intertainment then real science
like when they had a rather small boat as an example of titanic pulling people down when it went down
a such a small raft cant compare to titanic in ways of down pull
but they are ok fun
but if they bust a myth dont mean a 100% bust in my book
Maggy said:
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we have a fixed voltage (U) of 110 or 220V, depends where you live we can measure resistance (I) from the device that drops into the water to the feet of the tub, to the tap, to the drain
U=I.R in this case U=I1.R1+I2.R2...InRn
With an 80A fuse, the radio falling on the feet, the tap behind the back and the drain and two tub feet straight under it it seems likely that about 2/3 of 80A, well lets say 50A will strike you, 50 x 110 = 5500W That should boil the egg if not electrocute it
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Equations, I like! For the case you've calculated above, you consider that the full 80A is flowing. And weirdly, you seemingly considering that 2/3 flowing through a human body. Lets look at this, at the 50A you mentioned (yes, you are right, 5500W will cook you very well). Consider the worst case of U at 240V, your body will have to have (U/I = R) a resistance of 4.8Ohm, which is weirdly small, dont you think?
As with scousemartin's boil an egg, you will have to consider the large amount of water in the bath tub as oppose to the amount of water you use in boiling the egg (e.g. it would take really long for the water to boil) And, even IF the water has similar rate in raise of temperature, I'm sure the person involved will be pretty quick to jump out of the water (when a toaster hit the tub) before it gets boiling.
Oh... will the bullet actually pass though your body and hit the person you are protecting? I mean if its a typical 9mm and shoot at the chest from a minimum distance of 2m.
I am worried that my response will lead to seeing you on the darwin awards, but..
Almost certainly no, assuming center mass. But there are variables, the most important of which is the type of round; full metal jacket, hollow point variants, etc.
Try not to get dead.
do i dare suggest conducting practical experiments to verify this...preferably not on me...i could suggest a few names for our test subjects though...
i could suggest a few names for our test subjects though...
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may i suggest Steve jobs?
I know two people who shot themselves, one personally, one via t'interweb.
The first one lives in Israel and was at a shooting range with her partner, with no barriers between them.
He fired and an empty hot case went down her neck, causing her to flinch and pull her own trigger, sending the bullet across her forehead slicing it open just under the hair line.
The second wondered when he was a teenager, if a thick book could protect him from a point blank pistol shot.
Rather than shooting the book away from himself, he held it infront of his chest.
Many hours of heart surgery later he lived to tell the tale.
9mm are prefered by the police because they don't tend to pass through their targets, especially if they're using hollow points (unavailable to legitimate armies due to the Geneva convention) as these are designed to mushroom on impact.
Out of my Ruger SR9 (4.5 inch barrel) a 9mm fmj will go through 2 Colorado Springs phone books (1000+ pages) and a high performance hollow point (love Gold Dots or Hydrashocks) go through 1 1/2 phone books at around 30 feet.
I'm 5'7"ish, and had the phone held around my chest. Slipped out my hand and hit the floor, carpet. Would any problems occur from that drop/fall?
You tell us, does anything seem to be wrong?
Personally I've dropped this phone a hundred times on carpet and it's always fine. Hell, it's had a few run ins with pavement and it's good. More than I can say for my iPhone RIP.
Sent from my HTC Incredible S using XDA App
zingxao said:
I'm 5'7"ish, and had the phone held around my chest. Slipped out my hand and hit the floor, carpet. Would any problems occur from that drop/fall?
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Due to the gforces of the sudden deceleration, a problem may occur where the once seperate chemicals in the battery cell may have combined. There is now a very high risk of explosion.
However, there is a fairly simple workaround. While holding the phone upside down in your left hand, hop in a counterclockwise direction singing your country's national anthem backwards while hitting yourself on the head with a shoe. Hope this helps.
I've done worst with my stolen diamond...
I can remember it clearly as yesterday...
The Diamond was brand new: one of the first phone with G-sensor, so I installed the mighty app that turn is in a lightsaber!
Well, after 5 or 6 swing it slipped from my hand hitting the highest part of the door and then falling to the ground...
Not even a scratch!!!
Nonverbose said:
Due to the gforces of the sudden deceleration, a problem may occur where the once seperate chemicals in the battery cell may have combined. There is now a very high risk of explosion.
However, there is a fairly simple workaround. While holding the phone upside down in your left hand, hop in a counterclockwise direction singing your country's national anthem backwards while hitting yourself on the head with a shoe. Hope this helps.
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Thank you sir, for starting my day with a bellyful of laughter.
Otoh, if it works, do a reboot and check it out again, if its ok, then I guess its ok. I fumbled in catching my phone thrown to me from the first floor, fell and hit the gravel/mud berm/sidewalk of the driveway. Slight unpeeling of the black enamel of the aluminium bezel at the top left corner (on the front side) just near the headphone socket, but still working for almost a year now....
Sent from my HTC Incredible S
Nonverbose said:
Due to the gforces of the sudden deceleration, a problem may occur where the once seperate chemicals in the battery cell may have combined. There is now a very high risk of explosion.
However, there is a fairly simple workaround. While holding the phone upside down in your left hand, hop in a counterclockwise direction singing your country's national anthem backwards while hitting yourself on the head with a shoe. Hope this helps.
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hehehe
Speaking of dropping the phone.. I had dropped the phone from bike and it has scratches around the front side black panel part.. and I wish to replace it.. Can the cover be available?? I mean like the complete black part??
The incredible S is very durable and you shouldn't be too afraid of dropping your phone Im not saying that you're need to drop your phone all the time.
I had dropped it on concrete road , and its still fine though with few scratches
I been attack by a wild trol when cruiseing with my inc s ..damm he made me trow my inc s at him..thans to gorila glass,it really gorilla..:-D lolololol
Sent from my Htc Incredible S with beats Audio & Nik's Rom 3.5 :-D
Well, I dropped my phone a few days after I bought it, and the light sensor went caput.. The guys at the service center replaced it with a new phone for me though. Of course, I had not rooted the phone then - not sure if they are ok with replacement and stuff if the phone is rooted..
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hTC IncS on Virtuous Quattro RC3
I dropped mine a week or two ago on a ceramic floor while sitting down. My heart stopped beating as I hopelessly saw it fall to the ground but was rejoiced when I saw it didn't even have a ding!
I've dropped phone alot. The worst scenario which happened was 3 months ago.
I was waiting teacher on 4th floor and sit on bench while touching phone then i put hand on stair's waiting and hands were little sweaty and it dropped. I was like wtf?! Surely it's on first floor and burst into little pieces (I did get mini heart attack). Instantly i went downstairs and phone was laying on 3rd floor and seemed to be in one piece. Then I pressed power/sleep button. Everything worked. it did get a little scratch on it's drake, nothing major. It's still a mystery how did the phone get from 4th to 3rd , probably a 1/100 epic bounce and it fell like 3,5m to concrete stone floor. Even battery cover was attached. Seriously it's as tough as Nokia 3310. So that's my story, I'm very sleepy, and It's all true amazing, uh? Using Nik rom for now and I'm typing this on my HTC Incredible S