RL Circuit Calculator

Enter resistance and inductance to find the RL time constant, cutoff frequency, and current response.

Resistance R (ohms)

Inductance L (mH)

Supply Voltage (V) — optional, for current display

Time Constant τ = L/R

seconds

Cutoff Frequency

—

Steady-State Current

—

At 1τ (63.2%)

—

At 3τ (95.0%)

—

At 5τ (99.3%)

—

Inductive Reactance at fc

—

RL Circuit Formulas

τ = L / R

f_c = R / (2πL)

i(t) = (V/R)(1 − e^(−t/τ))

X_L = 2πfL

RC time constant.

LC resonance.

Turns ratio.

Op-amp gain.

V=IR.

ADC bits.