江蘇春晨電纜有限公司生產(chǎn)YCB橡套扁電纜 移動(dòng)扁電纜，

f the average power is zero, it means that the capacitor does not consume active power, and it does not mean that there is no power in the capacitor. There is energy exchange between the capacitor and the power supply, so the instantaneous power is not equal to zero. The product of the maximum value UI of instantaneous power is called reactive power, which is represented by the symbol QC. It reflects the maximum scale of the exchange energy between the capacitor and the power supply.

電容的無(wú)功功率計(jì)算公式

Calculation formula of reactive power of capacitor

Qc的單位為乏（var）或千乏（kvar）。

The unit of QC is var or kvar.

算一算

add up

題：已知電容器的電容量C=10μF，現(xiàn)分別將它接在⑴直流220V電源上；(2)工頻交流電壓有效值220V電源上；(3)500Hz、220V交流電源上，求電容的電流I和無(wú)功功率Qc。

Title: given that the capacitance of the capacitor is C = 10 μ F, it is connected to (1) DC 220V power supply; (2) power frequency AC voltage effective value 220V power supply; (3) 500Hz, 220V AC power supply, the current I and reactive power QC of the capacitor are calculated.

解：(1)在直流220V電源上因?yàn)橹绷麟妷旱念l率f=0，所以容抗：

Solution: (1) on the DC 220V power supply, because the frequency of DC voltage f = 0, the capacitive reactance:

算式

Formula

由計(jì)算結(jié)果可知，電容對(duì)直流相當(dāng)于開路；對(duì)高頻電流阻抗小，電流易通過；對(duì)低頻電流阻抗大，電流難通過。利用電容器的這種特性，可以將電容器制成濾波器YCB橡套扁電纜 移動(dòng)扁電纜

It can be seen from the calculation results that capacitance is equivalent to open circuit for DC; small impedance for high frequency current, easy to pass current; large impedance for low frequency current, difficult to pass current. Using this characteristic of the capacitor, the capacitor can be made into a filter