在 RLC 串聯(lián)交流電路中，流經電感元件與電容元件的電流為同一電流。由于電感電壓超前電流90°，電容電壓滯后電流90°，所以每時每刻，電感電壓總與電容電壓相反。當兩電壓幅值相等（感抗等于容抗）時，其電壓疊加值為零，即電感與電容構成的整體可等效視為短路。此時依據歐姆定律，電路電流可直接表示為電壓與電阻的比值，且電壓與電流相位一致。需注意，電感與電容兩端各自存在端電壓，其數值可能遠高于輸入電壓，此現象即被定義為串聯(lián)諧振過電壓。

What is the principle of series resonance?

In an RLC series AC circuit, the current flowing through the inductive and capacitive elements is the same current. Due to the inductor voltage leading the current by 90 ° and the capacitor voltage lagging the current by 90 °, the inductor voltage is always opposite to the capacitor voltage at all times. When the amplitudes of two voltages are equal (inductance equals capacitance), the voltage superposition value is zero, which means that the whole composed of inductance and capacitance can be equivalently regarded as a short circuit. According to Ohm's Law, the current in a circuit can be directly expressed as the ratio of voltage to resistance, and the voltage and current phases are consistent. It should be noted that there is a terminal voltage at both ends of the inductor and capacitor, which may be much higher than the input voltage. This phenomenon is defined as series resonant overvoltage.