ε = -dΦ/dtwhere ε is the induced emf and Φ is the magnetic flux.
ε = -L (di/dt)
ε₂ = -M (di₁/dt)
I(t) = I₀ sin(ωt)where I₀ is the peak current, ω is the angular frequency, and t is time.
Iₓ = I₀ / √2The RMS value is used to calculate power in AC circuits.
XL = ωL, XC = 1/(ωC)
Z = √(R² + (XL - XC)²)where R is the resistance.
f₀ = 1 / (2π√(LC))
P = Iₓ² Rwhere Iₓ is the RMS value of current and R is the resistance. The power factor (cos(φ)) determines how much of the total power is useful.
V₁ / V₂ = N₁ / N₂where N₁ and N₂ are the number of turns in the primary and secondary coils, respectively.