I = V / R
P = V · I = I 2 · R = V 2 / R
VT = V1 + V2 + V3 + ...
IT = I1 = I2 = I3 = ...
RT = R1 + R2 + R3 + ...
1/CT = 1/C1 + 1/C2 + 1/C3 + ...
LT = L1 + L2 + L3 + ...
VT = V1 = V2 = V3 = ...
IT = I1 + I2 + I3 + ...
1/RT = 1/R1 + 1/R2 + 1/R3 + ...
CT = C1 + C2 + C3 + ...
1/LT = 1/L1 + 1/L2 + 1/L3 + ...
V1 = VT ⋅ R1 / (R1+R2+R3+...)
I1 = IT ⋅ (R2+R3+...) / (R1+R2+R3+...)
電流迴路的壓降總和為零:
∑ Vi = 0
幾個電路元件之間的連接點稱為節點。
節點處的電流值之和為零:
C = Q / V
C = ε ⋅ A / l
ε 是以法拉每米 (F/m) 為單位的介電常數。
ε = ε0 ⋅ εr
ε 0是真空中的介電常數。
ε r是相對介電常數或介電常數。
IC(t) = C d VC(t) / dt
V C (t) = V C (0) + 1/ C ∫ I C (t)⋅ dt
VL(t) = L d IL(t) / dt
I L (t) = I L (0) + 1/ L ∫ V L (t)⋅ dt
WC = C⋅V 2 / 2
WL = L⋅I 2 / 2