7 ms·

For safety alone DC is not going to replace AC. The author seems to be confusing local use, and distance transmission.

thehappypm 5y ago
In what way is AC safer than DC? Ohm’s law says V=IR, that means your resistive body is gonna get shocked regardless of whether the voltage is constant or changing.
- cfraenkel 5y ago
  It isn't - both can kill you. DC results in a continuous muscle contraction, where AC makes for many contractions; DC 'let go' current is higher than AC; lethal AC current is also lower than DC. But we're talking mA here - house current will kill either way if it goes through the heart. source: https://www.brighthubengineering.com/power-plants/89792-ac-and-dc-shock-comparison/ https://www.brighthubengineering.com/power-plants/89792-ac-a...
  - unnouinceput 5y ago
    That's because the 220V AC is the integral (as in that math you learn in high-school) part of it. That 220V AC outlet actually has 630 V peak-to-peak voltage difference. That's why AC voltage is riskier than its DC counterpart, but that's because the numbers for AC are somehow misleading. Anyone who ever build an AC-to-DC converter knows that after you run your AC source through a rectifier bridge your get 315V at its exit. Then you use capacitors and maybe induction coils to "smooth" it, and that smoothing is what gets you your 220V DC source now.
- BenjiWiebe 5y ago
  Don't forget that AC can flow through capacitors.
  - thehappypm 5y ago
    What do you mean by that exactly?
    - unnouinceput 5y ago
      Get a capacitor that supports 700V minimum as highest applicable voltage, and a wire. Go to your socket outlet, put the capacitor in one hole, the wire in the other hole and see if you get shocked or not. Do the same (if you're still alive) with a DC source. Comeback here and let me know how the experiment went and also tell me why you skipped physics class in high-school when this was taught.
      - thehappypm 5y ago
        I know all about RLC circuits, I just fail to see how this makes it any safer than DC. Conversely, DC can flow through inductors, AC can’t.
        unnouinceput 5y ago
        AC can and will definitely flow through inductors, especially the 220V/60Hz one you have at outlet. I challenge you to connect an inductor, even one of several Henry's as value, to your outlet and to your hand and comeback here and tell me if it shocked you or not.
dhdc 5y ago
To transfer an equivalent amount of power to a given load, AC has a peak to peak voltage of about 170V compared to DC's constant 120V.
- unnouinceput 5y ago
  170V is peak to median. Peak to peak is double that (340V). More precisely the math formulae is: "AC voltage" x sqrt(2) - for median. And you double that for peak-to-peak

In what way is AC safer than DC? Ohm’s law says V=IR, that means your resistive body is gonna get shocked regardless of whether the voltage is constant or changing.

cfraenkel 5y ago
It isn't - both can kill you. DC results in a continuous muscle contraction, where AC makes for many contractions; DC 'let go' current is higher than AC; lethal AC current is also lower than DC. But we're talking mA here - house current will kill either way if it goes through the heart. source: https://www.brighthubengineering.com/power-plants/89792-ac-and-dc-shock-comparison/ https://www.brighthubengineering.com/power-plants/89792-ac-a...
- unnouinceput 5y ago
  That's because the 220V AC is the integral (as in that math you learn in high-school) part of it. That 220V AC outlet actually has 630 V peak-to-peak voltage difference. That's why AC voltage is riskier than its DC counterpart, but that's because the numbers for AC are somehow misleading. Anyone who ever build an AC-to-DC converter knows that after you run your AC source through a rectifier bridge your get 315V at its exit. Then you use capacitors and maybe induction coils to "smooth" it, and that smoothing is what gets you your 220V DC source now.
BenjiWiebe 5y ago
Don't forget that AC can flow through capacitors.
- thehappypm 5y ago
  What do you mean by that exactly?
  - unnouinceput 5y ago
    Get a capacitor that supports 700V minimum as highest applicable voltage, and a wire. Go to your socket outlet, put the capacitor in one hole, the wire in the other hole and see if you get shocked or not. Do the same (if you're still alive) with a DC source. Comeback here and let me know how the experiment went and also tell me why you skipped physics class in high-school when this was taught.
    - thehappypm 5y ago
      I know all about RLC circuits, I just fail to see how this makes it any safer than DC. Conversely, DC can flow through inductors, AC can’t.
      - unnouinceput 5y ago
        AC can and will definitely flow through inductors, especially the 220V/60Hz one you have at outlet. I challenge you to connect an inductor, even one of several Henry's as value, to your outlet and to your hand and comeback here and tell me if it shocked you or not.

dhdc 5y ago

To transfer an equivalent amount of power to a given load, AC has a peak to peak voltage of about 170V compared to DC's constant 120V.

unnouinceput 5y ago
170V is peak to median. Peak to peak is double that (340V). More precisely the math formulae is: "AC voltage" x sqrt(2) - for median. And you double that for peak-to-peak