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Edit: great approach to understand the matter: https://youtu.be/BGD-oSwJv3E?is=Fe1FimqTCvN-aY1u
I was looking at some transformers:
But also
If it outputs 12VA (12V * 1A) of apparent power, then it receives/works with (?) 12VA apparent power. That means that the current in my 230V wall outlet is 12 / 230 ≈ 0.05A. Even a button cell can supply 0.15A per hour... This leads my uninitiated head to believe, that it is mainly high voltages that are not compatible with life.
Please advise? 🙃
It's like mass and speed.
A fly travelling at 50kmh won't kill you A truck hitting you at 2kmh won't kill you
A truck smacking you at 50kmh is another story
12V at 1A = 12W / 12VA
230V at 1A = 230W / 230VA
That growth might lead one to surmise that voltage is the ‘killer’, but that’s not actually the case - Amperage is the key force multiplier that will dictate whether or not the shock is deadly.
Example - when you poke your friend and zap them, that’s an electrostatic discharge of 1,000+ Volts but it’s only around 0.0001 Amps and only lasts a few microseconds.
In addition to duration, Amperage is going to be the key force multiplier that determines how ‘deadly’ a shock might be.
So translating this into ARPG nomenclature: Ampere is base damage, and voltage is armor penetration, and your body resistance is armor. Low ampere above a certain threshold can still kill you if the voltage gets high enough, but high amperage can brute force its way with a help from a little bit of voltage. Did I get that right?
The transformer will output 12w of power and use just over 50ma, but your wall outlet can supply significantly more. Using the transformer to try to say voltage kills or that your outlet supplies the same as a battery isn't acurate.
Rubbing a glass rod with a silk cloth will generate thousands of volts but very low current. Power would be in the low millijoules. It will give you a nice shock, which would hurt, but isn't lethal.
A 12v car battery can output 700+ amps through low resistance. In the right conditions it can be lethal, though it would most likely result in burns.
Voltge pushs amperage through resistance. Ohms law (Voltage = Amps x Resistance) shows that as one value increases, the others adjust.
The simplified expression is voltage hurts, amperage kills. Mostly due to the high resistance of a body.
No. They ARE NOT decoupled. At all. Period. Unless you're an idiot in today's world.
While 12v can struggle to kill someone, it still can.
While 120v isn't the end of the world, it's still FULLY capable of murdering you depending on how the current flows.
The real answer is, and ONLY is, "it depends, and you do not like the answer".
MANY shitty power supplies are FULLY capable of killing a human. The real question is: does your local government properly regulate things? (the answer is NO for 80%+ of the population, including americans)
Its the volts that jolt, but the mills that kills is the saying I know.
What is left out is resistance, everything has resistance. Air, skin, clothes, whatever you are standing on. Sufficient resistance will protect you.
Basically, amps tell you how fast electricity is moving. If you have a certain amount of amps running through your body, it will kill you (I think technically no matter the voltage?).
Why doesn't every battery kill you? Electricity at low voltages doesn't have enough "strength" to push through your body, as your (electrical) ressistance is very high. The higher the voltage, the higher ressistance it can overcome.
So if you touch say 12 V, only very very few microamps will flow through your body, which doesn't matter.
When you touch 230 V, now the electricity is strong enough to push somewhere between 10 - 100 mA through your body, which will kill you.
(No guarantees that the amperage numbers here are correct, but the scale should roughly work out I hope).
It all boils down to $U = R \cdot I$ (Voltage = Ressistance * Current).
If you want to learn more about the subject, ElectroBoom has some great videos.
Way to completely and utterly ignore pathways through the body. MANY people survive serious shocks simply because the current doesn't pass through vital organs. See: literally ANY lightning strike survivor, or any idiot that survived touching high voltage lines.
The true, and ONLY reason people survive, is because the electricity that DID conduct through their body, did not conduct through critical body structures, like the brain-to-heart connection. Very little else matters. Someone can "survive" a lightning strike or electrical industrial accident, yet be a vegetable for the rest of their lives.
It is EXACTLY why the only correct course of action during an unprotected thunderstorm when you feel the static charge building, is to crouch down and put as much meat between your head and the ground as possible (by cupping your head and making sure your thighs, lower legs, and arms are in contact as much as possible). Then, if you get struck, it's the meat that takes the hit instead of your brain and core nervous system, "ideal" circumstances.
Very good explanation! Even i understood this, thank you!
Although this part caught my eye:
amps tell you how fast electricity is moving
Wouldn't you say it can rather be likened with data bandwidth? Like, how much current per time?
What do you think?
Yeah you're right, electricity flows at a constant speed. Throughput is the more fitting word I guess? Bandwidth to me sounds more like a theoretical max throughput.
So there is two main ways electricity can kill you. One is frequency and two just plain old cooking you from high power. AC current at around 60 hz causes muscles to spaz out and stop functioning, like your heart. This require very little current but high voltage to meet the breakdown voltage of your skin. Also has to go through your heart. The second way is just being so high power you basically explode or cook the from touching it.
this also happens with dc once voltage is high enough
You so utterly inadequately explain the problem as to be misinformation yourself... congrats!
For a real explanation for how electricity kills, see electroboom or styropyro's youtube videos on it.
It's 100% current, but the current that matters is the current through you. The resistance between your hands is roughly 3 kΩ at low voltages and about 1 kΩ at 220V. You need about 5 mA DC or 1 mA AC to feel anything, which means you need about 15V DC if you're the only resistance in the circuit.
The current at your outlet will be ~0.05A if the only path between hot and neutral is the transformer. If you add an alternate path, you allow for up to 25A or so before the breaker cuts the circuit. 25A would mean that the resistance between hot and neutral is about 8Ω. If you are the alternate path, there will be about 220V/1k=220mA going through you, which is about 8x the amount needed to cause you to go into cardiac arrest.
The only time that the current in the outlet while the transformer is connected would matter is if you were in series with the transformer. If you stuck a wire into each side of the outlet and connected one to one side of the transformer, then grabbed the other wire with one hand and the other side of the transformer with the other hand, you'd experience a shock of about 55 mA (0.05 A, like you calculated), which would still probably kill you.
The button cell doesn't do anything because it's 1.2V. That means its max current through your body is about 0.4 mA, or 0.0004A. It's also DC, which means that it affects your body about 5x less than the AC in your wall outlet.
Nope. Circuit breakers do not break on absolute current values. Ever. Period. At all. Even a basic spec sheet will inform you as much...
It's why many euro firms make fun of American standards: They're literally not expressive of reality.
Even GFCI's can shock the fuck out of you in certain circumstances.
Nope. Circuit breakers do not break on absolute current values.
Huh, TIL.
Ever. Period. At all.
That doesn't seem to be supported by my research. Standard breakers are designed to trip based on a function of over-current and time, but that doesn't preclude any breakers from using current alone.
Even a basic spec sheet will inform you as much...
It won't. I checked. A more detailed spec sheet will, but not a basic one.
It's why many euro firms make fun of American standards: They're literally not expressive of reality.
They sure look like they are. The rating is the current that the breaker can sustain indefinitely at the reference temperature. And it sure looks like the EU rates them the same way.
Even GFCI's can shock the fuck out of you in certain circumstances.
Of course they can. You aren't a ground fault. A load of 100mA on a GFCI is perfectly normal, and the same load will kill a human very quickly.
If you cannot understand the BASIC fact that a circuit breaker can ABSOLUTELY conduct more energy than its rating before it pops... then you are simply too stupid to understand what I said. Period. Absolutely. Good job being so dim.
They look like they are ... to an ignorant incapable of reading comprehension. Which is one reason why the standards are made fun of.
Care to explain your reasoning, then? Or did you just want to feel smug?
Your whole comment was great but this part in particular cleared up things really well for me:
The only time that the current in the outlet while the transformer is connected would matter is if you were in series with the transformer. While it's obvious now that you mention it, I totally overlooked the fact that when people get shocked, they don't come in contact with the circuit in a serial manner/configuration. This is probably why I calculated the values so overly simplistically, I think. Anyway, thanks! 😊
I was a little worried that that part would distract from the overall message, so I'm glad I ended up leaving it in and I appreciate you telling me that it helped.
It's not so simple as amps or voltage.
Bonkers 🤣
Thanks anyway! 😊
Maybe try this one . It also got electrobooms comment of approval!
Cool! This made things really clear! It's a multifaceted matter, not just "volts VS. amps". Thanks! 😊