Comment on Just vibing
ChaoticNeutralCzech@feddit.org 2 weeks ago
The electrons don’t move very quickly either. And it’s current times voltage that delivers power. Simplifying to a single harmonic (pure sine voltage source and a linear RLC load), you need to know the product of the voltage’s and current’s amplitude (in VA, voltamps) but also their power factor or cos φ, the cosine of phase beetween them. If the cosine is zero, it’s a purely reactive (L/C) load with a phase of ±90° and no power is consumed overall. If the cosine is negative, power is actually being generated by the device you’re measuring (for instance, old elevators and escalators with synchronous motors are actually delivering power into mains when enough people are travelling down).
Morphit@feddit.uk 2 weeks ago
Amps are not joules / second;- that would be Watts. Amps = Coulombs / second, and Volts = Joules / Coulomb. That’s why multiplying them gives you power in Watts.
That’s true instantaneously but as you say, if the current or voltage are alternating then you can’t just use the AC current and voltage to get real power like you can with DC.
ChaoticNeutralCzech@feddit.org 2 weeks ago
You are correct, that was a mistake.
However, although symbols of quantities named after scientists (V, A, W, C, J, Ω, H, F, T, Hz, S, K, N, Pa, Bq, R, Ci) are uppercase, they are lowercase when written out (volt, amp(ère), watt, coulomb, joule, ohm, henry, farad, tesla, hertz, siemens, kelvin, newton, pascal, becquerel, roentgen, curie) to differentiate them from the surnames. And yes, that’s why the Claude Litre hoax was created.