Science & engineering
RL current rise calculator
Explore an ideal series RL step response and stored magnetic energy.
A clear answer. Here’s how.
For a series RL circuit initially carrying zero current, τ=L/R and I(t)=(V/R)(1−e^(−t/τ)). Uses expm1 for small elapsed times. Reports final current, instantaneous current, inductor voltage and stored energy ½LI². R includes all idealised series resistance. No saturation, parasitics or component ratings are predicted.
See a worked example
Worked example
A fixed demonstration, separate from the values you enter above.
- Total series resistance (Ω)
- 10
- Inductance (mH)
- 100
- Applied DC step (V)
- 12
- Elapsed time (ms)
- 10
Example result
- Time constant
- 0.01 s
- Final steady current
- 1.2 A
- Current at elapsed time
- 0.758544670594 A
- Inductor voltage at elapsed time
- 4.41455329406 V
- Stored magnetic energy
- 0.0287695008643 J
- Fraction of steady current
- 63.2120558829%