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Ohm's law & power
The relationship every electrician leans on. Enter any two of voltage, current, resistance or power — get the other two instantly.
Back to AstralLearnEnter any two values — we solve the other two.
Solved
V = I × RP = V × IP = I² × RP = V² / R
The wheel: V = I×R and P = V×I are the two you use most; the rest fall out algebraically (P = I²R, P = V²/R, V = √(P·R), and so on). This is DC / resistive; add power factor for reactive AC loads.
Educational reference. Sizing a real circuit? Call a licensed C-10 → (650) 562-8594.
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