Submitted 1 hour ago by akunohana@piefed.blahaj.zone to [deleted]
Voltage kills, not current... right?
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? 🙃
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.
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.
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 is Voltage = Amps x Resistance. It 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”.
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.
Check out www.youtube.com/watch?v=XDf2nhfxVzg
Maybe try this one . It also got electrobooms comment of approval!
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.
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 at the same 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.
If you put your finger on the primary, the current will increase by an order of magnitude or so.
kkj@lemmy.dbzer0.com 22 minutes ago
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.