Alternating current

Electromotive force of alternating current
ε = B*S*ω

Electromotive force of alternating current
e = ε_m sin(ωt)

Maximum intensity of alternating current
I_m = ε_m / R

Effective value of alternating current intensity
I_ef = I_m / saknis(2)

Average power of of alternating current
p_vid = I_m^2 * R / 2

Effective value of alternating current voltage
U_ef = U_m / saknis(2)

Voltage of alternating current
U = U_m cos(ωt)

Maximum intensity of alternating current
I_m = U_m * C*ω

Capacitive reactance
X_c = 1 / (C*ω)

Intensity and capacitive reactance of alternating current
I  = U / X_c

Intensity and inductive reactance of alternating current
I  = U / X_L

Inductive reactance
X_L = ωL

Ohm's Law for alternating current (AC) circuit
X = saknis(R^2+(X_L - X_C)^2)

Ohm's Law for alternating current (AC) circuit
X = saknis(R^2+(ω*L - 1 / (C*ω))^2)

Phase difference between current and voltage of alternating current (AC)
tan(φ) = (X_L - X_C) / R

Resonance in alternating current (AC) circuit
U = I * saknis(L/C)

The first formula of transformer: voltage
U1 / U2 = N1 / N2

The second formula of transformer: current intensity
I1 / I2 = N2 / N1