Formula and example
How it is calculated
τ = L/R; I(t) = (U/R) × (1 − e^(−t/τ)); E = ½ × L × I²
Worked example
100 mH and 10 Ω give τ = 10 ms. With a 5 V supply, the current after 10 ms is approximately 0.3161 A.
Things to check
- The initial current is zero. The current approaches U/R.
- The ideal model excludes saturation, winding capacitance and additional temperature-dependent resistance changes.