AC Circuits Formulas
A complete list of ac circuits formulas, covering RMS values, capacitive and inductive reactance, impedance, and resonant frequency.
7 formulas. Use the interactive searcher to solve for any variable and convert units.
Open the interactive searcher →RMS voltage
V_rms = V₀ / √2
V_rms RMS voltageVV₀ peak voltageV
RMS current
I_rms = I₀ / √2
I_rms RMS currentAI₀ peak currentA
Capacitive reactance
X_C = 1 / (2π·f·C)
X_C capacitive reactanceΩf frequencyHzC capacitanceF
Inductive reactance
X_L = 2π·f·L
X_L inductive reactanceΩf frequencyHzL inductanceH
Impedance (RLC)
Z = √(R² + (X_L − X_C)²)
Z impedanceΩR resistanceΩX_L inductive reactanceΩX_C capacitive reactanceΩ
Resonant frequency
f₀ = 1 / (2π·√(L·C))
f₀ resonant frequencyHzL inductanceHC capacitanceF
Inductor energy
E = ½·L·I²
E energyJL inductanceHI currentA