Ở trạng thái cân bằng V L + V C = 0 {\displaystyle V_{L}+V_{C}=0} L d 2 i d t 2 + 1 C ∫ i d t = 0 {\displaystyle L{\frac {d^{2}i}{dt^{2}}}+{\frac {1}{C}}\int idt=0} d 2 i d t 2 + 1 L C i = 0 {\displaystyle {\frac {d^{2}i}{dt^{2}}}+{\frac {1}{LC}}i=0} d 2 i d t 2 = − 1 T i {\displaystyle {\frac {d^{2}i}{dt^{2}}}=-{\frac {1}{T}}i} i = A S i n ω t {\displaystyle i=ASin\omega t} ω = 1 T {\displaystyle \omega ={\sqrt {\frac {1}{T}}}} T = L C {\displaystyle T=LC} Ở trạng thái đồng bộ Z L = − Z C {\displaystyle Z_{L}=-Z_{C}} ω o = ± j 1 T {\displaystyle \omega _{o}=\pm j{\sqrt {\frac {1}{T}}}} T = L C {\displaystyle T=LC} V L = − V C {\displaystyle V_{L}=-V_{C}} v ( θ ) = A S i n ( ω o t + 2 π ) − A S i n ( ω o t − 2 π ) {\displaystyle v(\theta )=ASin(\omega _{o}t+2\pi )-ASin(\omega _{o}t-2\pi )}