Free · Thermodynamics and heat calculators 🌡️

Resistive Current, Time & Heat Energy

Calculate energy dissipated in a fixed resistance by a constant current over a positive duration.

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

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Formula and method

A current of 2 A through 3 Ω for 10 seconds dissipates 120 J. Reversing the current sign gives the same dissipated energy.

Dissipated energy = current² × resistance × elapsed time

Worked example

Enter these known values and leave the other values blank.

Constant current or appropriate RMS current
2 A
Fixed resistance
3 Ω
Elapsed duration
10 sec
Electrical energy dissipated as heat
120 J

Assumptions and limitations

  • Resistance, duration and energy are strictly positive; current is nonzero in this retained model. Either current sign gives the same energy.
  • Assume constant resistance and current. For AC, RMS current can be used when it represents the relevant averaging interval and resistance is fixed.
  • The inverse returns the positive current magnitude. The calculation is electrical energy dissipation, not temperature rise or heat retained in an object. The fixed time conventions use 365.25 days per year and one twelfth of that per month.

Common questions

Why does negative current still produce positive heat?

Current is squared. Reversing its direction through the same positive resistance leaves resistive dissipation unchanged.

Can I calculate the final temperature directly?

No. Temperature change also depends on heat capacity, heat transfer, phase changes and how resistance varies with temperature.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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