I didn't know they ran power through the tracks like that, also why does it pulse?
[QUOTE=Hendo;43484534]I didn't know they ran power through the tracks like that, also why does it pulse?[/QUOTE]
Its a clever signalling system devised in the 20s, since we had no computers, internet, phone network so there was no easy way to give drivers information about track status or anything, especially in bad weather.
Different countries have different systems, but the concept is the same, pulses are sent down the track from each signalling box. The pulses are picked up by a sensor on the bottom of the train and then the frequency is displayed as pulses/min. Different frequencies mean different things, for example whether or not the next signal is on stop / go and if it has a speed restriction.
Though if the track has a third rail running alongside it you definitely don't want to go near that, they usually operate at amperages that will instantly kill or seriously hurt someone.
Judging from the accent, these are Ukrainians.
[QUOTE=Cushie;43484673]Its a clever signalling system devised in the 20s, since we had no computers, internet, phone network so there was no easy way to give drivers information about track status or anything, especially in bad weather.
Different countries have different systems, but the concept is the same, pulses are sent down the track from each signalling box. The pulses are picked up by a sensor on the bottom of the train and then the frequency is displayed as pulses/min. Different frequencies mean different things, for example whether or not the next signal is on stop / go and if it has a speed restriction.
Though if the track has a third rail running alongside it you definitely don't want to go near that, they usually operate at amperages that will instantly kill or seriously hurt someone.[/QUOTE]
That's actually incredibly clever.
this must be how they made the newer battlefield theme songs
[QUOTE=Araknid;43485107]this must be how they made the newer battlefield theme songs[/QUOTE]
It almost sounds like it, just missing some beats. Maybe someone could try remixing it?
[media]http://www.youtube.com/watch?v=iRN62IebC04[/media]
[QUOTE=Cushie;43484673]Its a clever signalling system devised in the 20s, since we had no computers, internet, phone network so there was no easy way to give drivers information about track status or anything, especially in bad weather.
Different countries have different systems, but the concept is the same, pulses are sent down the track from each signalling box. The pulses are picked up by a sensor on the bottom of the train and then the frequency is displayed as pulses/min. Different frequencies mean different things, for example whether or not the next signal is on stop / go and if it has a speed restriction.
Though if the track has a third rail running alongside it you definitely don't want to go near that, they usually operate at [b]amperages[/b] that will instantly kill or seriously hurt someone.[/QUOTE]
You mean voltage.
A regular AA battery can deliver more than the required current to kill a person but because of the linear relationship between resistance and current, you need a high enough voltage to deliver enough current to a persons heart through human skin and tissue.
This is why a car battery, which can deliver 50+ amps to a starter motor won't kill you when you touch the terminals, because it's only 12 volts and skin has a resistance of several thousand ohms.
The reason a third rail is dangerous isn't because it's high current but because it's high voltage.
Rate disagree if you don't know how electricity works.
[QUOTE=chipset;43485659]You mean voltage.
A regular AA battery can deliver more than the required current to kill a person but because of the linear relationship between resistance and current, you need a high enough voltage to deliver enough current to a persons heart through human skin and tissue.
This is why a car battery, which can deliver 50+ amps to a starter motor won't kill you when you touch the terminals, because it's only 12 volts and skin has a resistance of several thousand ohms.
The reason a third rail is dangerous isn't because it's high current but because it's high voltage.
Rate disagree if you don't know how electricity works.[/QUOTE]
p.sure its a mixture of both. Also the minimum amount of amperage to cause violent muscle spasms that pose a risk to a persons life is not within the capacity of AA batteries unless you somehow run it across the heart all you're gonna do at most is cause them to twitch some, as far as I know.
It's not the voltage that kills you, it's the amperage.
If you have 0 amps, it doesn't matter how big the volts are, you won't die.
My brother once walked over a broken 20 amp power cord in our garage. It zapped all the lights out in our house and his shoe turned all black. Almost died that day.
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holy holy fuck i was so god damn wrong lmfao.
technically it's true that it's the current that kills, but you need high enough voltage.
the current is directly determined by the voltage and the resistance of an object the current is going through.
Say you have 1500 volts going through human skin which has the resistance of 1500 ohms on average.
I (current) = V (Voltage) divided by R (Resistance).
1500V divided by 1500 equals 1. That's 1 ampere and it's enough to kill you.
[QUOTE=Saturn V;43489247]It's not the voltage that kills you, it's the amperage.
If you have 0 amps, it doesn't matter how big the volts are, you won't die.
My brother once walked over a broken 20 amp power cord in our garage. It zapped all the lights out in our house and his shoe turned all black. Almost died that day.[/QUOTE]
here we go..
[QUOTE=Siemz;43484958]That's actually incredibly clever.[/QUOTE]
A lot of things involving trains are amazing inventions. Especially when you take into account how old the ideas are and how they are still crucial to the safe running of a railway. In the UK (and I assume other countries) they use track circuits which are pretty amazing, they run power through one rail and if it comes back down the other (because the train has connected the two rails) they know a section of track is occupied.
Simple, but incredibly important to safety.
Russians have devised a way to crack even a Nokia phone. I'd actually be surprised if it were anywhere else.
[QUOTE=chipset;43485659]You mean voltage.
A regular AA battery can deliver more than the required current to kill a person but because of the linear relationship between resistance and current, you need a high enough voltage to deliver enough current to a persons heart through human skin and tissue.
This is why a car battery, which can deliver 50+ amps to a starter motor won't kill you when you touch the terminals, because it's only 12 volts and skin has a resistance of several thousand ohms.
[B]The reason a third rail is dangerous isn't because it's high current but because it's high voltage.[/B]
Rate disagree if you don't know how electricity works.[/QUOTE]
You're completely right except for this. The reason the third rail is dangerous is because of both the high current and voltage it delivers. You need [I]both [/I]to kill a person - high enough voltage to overcome the resistance of skin and flesh and high enough current to actually stop the heart (not that much really).
Let's not forget that a stungun can usually deliver about 500 kV but it doesn't kill you. You already gave an example concerning high current + low voltage.
Also, fyi saying "disagree if you're wrong" makes you sound like an absolute pillock, even when you're right.
[editline]11th January 2014[/editline]
[QUOTE=Saturn V;43489247]It's not the voltage that kills you, it's the amperage.
If you have 0 amps, it doesn't matter how big the volts are, you won't die.
My brother once walked over a broken 20 amp power cord in our garage. It zapped all the lights out in our house and his shoe turned all black. Almost died that day.[/QUOTE]
You can't have 0 amps in a system - it means current isn't flowing, i.e. nothing's happening.
[QUOTE=Stopper;43490519]You're completely right except for this. The reason the third rail is dangerous is because of both the high current and voltage it delivers. [B]You need [I]both [/I]to kill a person[/B] - high enough voltage to overcome the resistance of skin and flesh and high enough current to actually stop the heart (not that much really).[/QUOTE]
Yes, which was exactly what he stated earlier in his post.
[QUOTE=Chipset]A regular AA battery can deliver more than the required current to kill a person, but because of the linear relationship between resistance and current, you need a high enough voltage to deliver enough current to a persons heart through human skin and tissue.[/QUOTE]
I'm fairly certain his point with
"[B]The reason a third rail is dangerous isn't because it's high current but because it's high voltage."
[/B]
was that it doesn't matter whether we're talking about (for instance) 50A or 100A, at a high enough voltage both will kill you instantly.
-snip-
The Nokia has a crack in it. Must be fake.
[QUOTE=Saturn V;43489247]It's not the voltage that kills you, it's the amperage.
If you have 0 amps, it doesn't matter how big the volts are, you won't die.
My brother once walked over a broken 20 amp power cord in our garage. It zapped all the lights out in our house and his shoe turned all black. Almost died that day.[/QUOTE]
I always though that was a dumb saying. You can't have one without the other. High currents through a human are impossible to achieve without a high voltage.
Every time a thread mentions electricity this shit springs up.
You could get some capacitors and a bridge rectifier in there and probably produce a pretty steady output voltage.
Sorry, just finished soldering a MintyBoost USB charger and its mechanics are stuck in my head :v:
So I'm sitting reading this thread like "Oh yeah, I should definitely test this next time I'm around railroad tracks with a multimeter". Five minutes later I realize there's railroad tracks 50ft from my front door. So I went to check it out, works here too! (California) I was only picking up about 1.2 volts, but it oscillated at roughly the same rate as in the video.
Moral of the story: Living next to railroad tracks isn't nearly as bad as you would think.
How do people still say "it's not the volage that kills, it's the amps"?
That quote has so many times been disproven and laughed at.
[QUOTE=Saturn V;43489247]It's not the voltage that kills you, it's the amperage.[/QUOTE]
You can't have amps without voltage. That's the simplest way to put it when this comes up.
[QUOTE=paul simon;43496363]How do people still say "it's not the volage that kills, it's the amps"?
That quote has so many times been disproven and laughed at.[/QUOTE]
Technically the quote isn't wrong. People misusing it are.
Well shit! This is genius.
its not the electrocution that kills, its the resulting heart failure
The amperage is what actually kills you, though, saying it isnt is just like misusing it on the other end of the spectrum.
[QUOTE=chipset;43485659]You mean voltage.
A regular AA battery can deliver more than the required current to kill a person but because of the linear relationship between resistance and current, you need a high enough voltage to deliver enough current to a persons heart through human skin and tissue.
This is why a car battery, which can deliver 50+ amps to a starter motor won't kill you when you touch the terminals, because it's only 12 volts and skin has a resistance of several thousand ohms.
The reason a third rail is dangerous isn't because it's high current but because it's high voltage.
Rate disagree if you don't know how electricity works.[/QUOTE]
Again, combination of the two.
Yes, technically its possible for only few mA to send your heard into fibrillation with enough voltage to overcome resistance, but those lines usually operate with enough voltage (800-2000) and enough current to instantly kill you on touch.
Its safer to operate on the assumption that high current usually means there's enough voltage and vice versa.
Food for thought, a static shock where you see a spark can be anywhere between 1000-10,000V
[QUOTE=Stopper;43490519]You can't have 0 amps in a system - it means current isn't flowing, i.e. nothing's happening.[/QUOTE]
incorrect! what do you think static electricity is? it can be 10kV+ but it has 0 amps so it hurts but doesn't do any actual damage
These guys should take the same setup and charge it with a pretty beefy tuned circuit. Power from the air (Given a strong enough carrier frequency)
[QUOTE=Cushie;43497986]The amperage is what actually kills you, though, saying it isnt is just like misusing it on the other end of the spectrum.
Again, combination of the two.
Yes, technically its possible for only few mA to send your heard into fibrillation with enough voltage to overcome resistance, but those lines usually operate with enough voltage (800-2000) and enough current to instantly kill you on touch.
[b]Its safer to operate on the assumption that high current usually means there's enough voltage and vice versa.[/b]
Food for thought, a static shock where you see a spark can be anywhere between 1000-10,000V[/QUOTE]
That doesn't really make any sense though, high voltage systems that an average person is likely to encounter are usually relatively low current and high current systems that a regular person is likely to encounter is usually relatively high current. Going by that I should be terrified of the microwave oven transformer I rewound to kick out over 1000 amps. Except since power is the product of voltage and current, if I were to assume it was also high voltage I would have to assume it was very high power, when in reality I would say (though I haven't tried) it's completely safe to lick the output of that transformer, because it only outputs 2.5 volts open circuit.
The assumption should be that if a circuit is high voltage it's dangerous. This is why warning sings say "danger high voltage" and not "danger high current".
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