Hence the signs saying “DANGER HIGH VOLTAGE”
I always thought that was a dumb saying because voltage is specifically what allows there to be a lethal current.
SaharaMaleikuhm@feddit.org 1 day ago
druidjaidan@lemmy.world 1 day ago
It’s a very dumb saying. If you don’t have the volts you won’t get the amps to kill you that’s ohms law.
However, there are plenty of harmless high voltage scenarios as well. Situations with high voltage, but no power.
So really you need both.
booly@sh.itjust.works 21 hours ago
In static electric fields, sure. But the real world has rapidly changing electric fields, and mapping concepts like voltage or resistance to a time dimension starts to require imaginary numbers (and the complex analogue to resistance goes by a different name of impedance). And once you’re modeling electricity through those concepts, you can have high current in a particular moment in time where the voltage might not be high. Or where the implied voltage is very high but was actually more of an effect than a cause.
In other words, if you’re simply talking about “resistance,” you’re already in the wrong domain to be analyzing electrical safety properly.
mexicancartel@lemmy.dbzer0.com 1 day ago
Its the “power” that kills you. Power depends on you as well as voltage.(Your resistance determine the current and time period of current flow also matters)
candybrie@lemmy.world 1 day ago
I think people just don’t understand ohm’s law. They seem to think voltage and current are unrelated to each other.
TheFogan@programming.dev 1 day ago
I suppose it’s half right. Obviously OHMs law is the triangle.
So you get a high voltage, running through a high resistance, it won’t kill you. The problem is people interpret it in a way that seems to think raising the voltage without raising the resistance is just fine.
candybrie@lemmy.world 1 day ago
It’s kinda hard to raise your body’s resistance a ton outside of not making good contact (e.g. wearing rubber boots/gloves). Things like your skin being moist lower resistance, but I’m not sure it’s really that much of a safety factor when dealing with high voltage.
TheFogan@programming.dev 1 day ago
I think the general gist is… not as much your body’s resistance as the circuit as a whole. IE a high voltage power source traveling through a high resistance circuit, vs touching the high voltage source directly.
booly@sh.itjust.works 1 day ago
Voltage and current are related, of course, but Ohm’s law is just a simplification of circuit theory for static circuits, and the version most are taught early on assume zero inductance and zero capacitance in the circuit. Drop in an alternating current, some capacitors and inductors, and you’ve got yourself a more complex situation, literally, with the scalar real number representing resistance replaced with the complex number representing impedance.
And when you have time variance that isn’t a simple sinusoidal wave of electric potential coming from a source, even the definition of the word “voltage” starts requiring vector calculus to even be a coherent definition.
So when I take a simple battery of DC cells to create a low voltage power source, I can still induce current using some transformers and inductors (which store energy in magnetic field) and abruptly breaking open the circuit so that the current still arcs across high resistance air. That’s the basic principle of how a spark plug works. In those cases, you’re creating immense voltages for a tiny amount of time, but there’s never any real risk of significant current being pushed through any part of a person’s body. And as soon as you draw off some of the current, the voltage immediately drops as you deplete the stored energy wherever it is in the system.
And anything designed to deliver an electric shock to a person (or animal) tends to be high voltage, low current. Tasers, electric fences, etc.
So it’s current that matters for safety. A high voltage doesn’t always induce a high current. And current can cause problems even at relatively low voltages.