Comments by "Alejandro Nava" (@altuber99_athlete) on "Ohms Law Explained - The basics circuit theory" video.

  1. Voltage is not the same as EMF.
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  2. What Ohm’s law says is that in some devices/materials under some circumstances, the (instantaneous) current through the device/material is directly proportional to the (instantaneous) voltage across the device/material. This can happen only if the resistance is constant. Thus, Ohm’s law also says that in some devices/materials under some circumstances, the (DC/static) resistance is constant for a given device/material for different values of voltage and current. And what if the resistance is not constant? Then voltage is not directly proportional to current, so the device/material doesn’t obey Ohm’s law, and it has a variable resistance; we can still use the equation v = R i to define resistance, but we can no longer call it Ohm’s law.
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  3. The triangle is definitely ridiculous. As you said, people who use can’t remember just one equation and use algebra to solve for the other two quantities. Also, if they can’t even remember V = R I, I wonder if they can remember the active power formula, or the inductor or capacitor equations, or the quadratic formula.
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  4.  @ChinhLe-jm1mf  If voltage and/or current are time-varying, and the user meant active power, and in your formula you used instantaneous voltage and instantaneous current, or if you used and in your formula you used RMS voltage and RMS current, then your formula is wrong. (P =/ V_rms I_rms, P =/ v(t) i(t).) If voltage and/or current are time-varying, and the user meant instantaneous power, and in your formula you used instantaneous voltage and instantaneous current, then your formula is correct. (p(t) = v(t) i(t).)
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