basic

RL Series Circuit Current Build-Up Calculator

i(t) = I_max · (1 − e^(−t/τ)), τ = L/R.

Compute the transient current in a series RL circuit driven by a DC source after the switch closes: i(t) = (V/R) · (1 − e^(−t·R/L)). Reports the steady-state current, the time constant τ = L/R, and i(t) at the chosen time.

Dr. Helena Ortiz By Dr. Helena Ortiz
Published Last reviewed 1 min read

Inputs

V
Ω
H
s

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

i(t) = (V/R) · (1 − e^(−t·R/L)); τ = L/R.

In depth

Compute the transient current in a series RL circuit driven by a DC source after the switch closes: i(t) = (V/R) · (1 − e^(−t·R/L)). Reports the steady-state current, the time constant τ = L/R, and i(t) at the chosen time.