What circuit model does this worksheet use?

One finite positive linear resistance at one operating state, using either steady DC magnitudes or RMS magnitudes for a purely resistive sinusoidal AC load.

Does P = V I apply to every AC load?

No. For a general AC load, real power depends on waveform and phase or power factor. This worksheet's AC route is restricted to a purely resistive sinusoidal load using compatible RMS values.

Why are some zero inputs rejected?

Some zero pairs imply zero or infinite resistance, or an indeterminate 0 divided by 0. The worksheet promises a finite positive resistance and rejects those limiting cases instead of emitting NaN or Infinity.

Is calculated power a resistor power rating?

No. It is operating-point dissipation only. Component rating requires temperature, derating, tolerances, transients, cooling, environment and manufacturer limits.

Electrical operating-point worksheet

Finite Linear Resistor

Use two compatible magnitudes from one finite positive linear resistance at one operating state. General AC impedance, phase, nonlinear loads and component rating are outside this worksheet.

V = I RP = V IFinite R > 0

Operating-point result

Dissipated real power

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Voltage magnitude

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Current magnitude

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Weerstand

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Conductance G = 1/R

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Calculated power is operating-point dissipation, not a resistor power rating, safety limit or energy value.

General engineering relations used

V = I R | P = V I = I²R = V²/R | G = 1/R

V is volts, I amperes, R ohms, P watts and G siemens. All inputs and outputs are magnitudes for a passive dissipative resistance.

Zero handling

Zero voltage is valid with known positive resistance; zero current is valid with known positive resistance; zero power is valid with known positive resistance. Other zero pairs can imply R = 0, R → ∞ or 0/0, so they are rejected rather than displayed as a finite answer.

AC limitation: replacing R by a complex impedance is not enough to retain every formula shown here. For a general AC load, phase/waveform and real, reactive and apparent power must be distinguished. This page only supports a purely resistive sinusoidal load with RMS V and I.

Excluded

Sources, signed power flow, negative/differential resistance and nonlinear or temperature-varying elements.
Complex impedance, inductance, capacitance, harmonics, power factor and three-phase systems.
Open/short-circuit limiting resistance, uncertainty propagation and meter loading.
Energy consumption, component rating, derating, transients, thermal rise and electrical safety decisions.

Bronnen

NIST explicitly states the measurement relation I = V/R. The same-two-points and passive-resistor derivations are documented in the open Lessons in Electric Circuits. These are general relations, not an ISO compliance calculation.