江蘇春晨電纜有限公司生產(chǎn)JHG JHXG電機引接線 耐高溫，

容抗反映了電容元件對交流電流阻礙能力的大小，它與C、f成反比。在相同電壓作用下，按Q=CUc式，C越大，說明它容納的電荷量越大，則它對電流的阻礙能力越小，電流就越大；若f越高，即電容的充電、放電過程越快，說明電容對電流的阻礙能力越小，電流也就越大。所以一個電容元件，在不同頻率的正弦電壓作用下，其對電流的阻礙作用是不同的，頻率越高，Xc越小，電流越易通過。如果f=0，Xc=∞，即直流電流不能通過電容元件。直流電路中若有電容元件，電路在穩(wěn)態(tài)時相當于開路?？梢?，在電路中，電容有隔直流通交流的作用。

The capacitive reactance reflects the capacity of the capacitor to block the AC current, which is inversely proportional to C and F. Under the same voltage, according to q = CUC formula, the larger C is, the greater the charge it holds, the smaller its blocking ability to current is, and the greater the current is; if f is higher, that is, the faster the charging and discharging process of capacitance is, the smaller the blocking ability of capacitance to current is, the greater the current is. Therefore, under the action of sinusoidal voltage with different frequency, the blocking effect of a capacitor on the current is different. The higher the frequency is, the smaller the XC is, and the easier the current is to pass through. If f = 0, XC = ∞, that is, the DC current cannot pass through the capacitor element. If there is capacitor in DC circuit, the circuit is equivalent to open circuit in steady state. It can be seen that in the circuit, capacitance has the function of isolating direct current and alternating current.

電容電路中的電流、電壓波形如圖b所示。

The current and voltage waveforms in the capacitor circuit are shown in Figure B.

電流與電壓的相位關(guān)系

Phase relationship between current and voltage

電流與電壓的相位關(guān)系是，電流超前電壓90°，或電壓落后電流90°。用相量形式表示，電流與電壓的關(guān)系有：

The phase relationship between current and voltage is that current leads voltage by 90 ° or voltage lags current by 90 °. In the form of phasor, the relationship between current and voltage is as follows:

電流電壓關(guān)系相量表示

Phasor representation of current voltage relationship

上相量式既表示了電壓與電流的數(shù)值關(guān)系，又表示了它們的相位關(guān)系。-ji說明電壓相量是在電流相量的基礎(chǔ)上向順時針方向旋轉(zhuǎn)了90°，電壓、電流之間的相位差角為90°。電流在相位上超前電壓90°。JHG JHXG電機引接線 耐高溫

The upphasor represents not only the numerical relationship between voltage and current, but also their phase relationship. -Ji indicates that the voltage phasor rotates 90 ° clockwise based on the current phasor, and the phase difference angle between voltage and current is 90 °. The current leads the voltage 90 ° in phase.

功率關(guān)系

Power relation

電容電路的瞬時功率：

Instantaneous power of capacitor circuit:

電容電路瞬時功率計算公式

Calculation formula of instantaneous power of capacitor circuit

瞬時功率pc的波形如圖d所示，從圖中可以看出，pc的幅值為UI，頻率為2ω，即以2倍于電壓的頻率按正弦規(guī)律變化。當u、i同是正值或負值時，如圖d中第1、第3個1/4周期，pc為正，說明在這個時段內(nèi)，電容從電源吸收電能并將電能儲存起來；當u、i中有一個是負值時，如圖d中第2、第4個1/4周期，pc為負值，即在這個時段內(nèi)電容將儲存的電能送回電源。瞬時功率正、負半周曲線包圍的面積相等，說明電容從電源吸收的能量等于它送回電源的能量，即：

The waveform of instantaneous power PC is shown in Figure D. from the figure, it can be seen that the amplitude of PC is UI, and the frequency is 2 ω, that is, the frequency that is twice the voltage changes according to the sine law. When u and I are both positive or negative, as shown in the first and third 1 / 4 cycles of figure D, PC is positive, indicating that during this period, the capacitor absorbs electric energy from the power supply and stores it; when one of u and I is negative, as shown in the second and fourth 1 / 4 cycles of figure D, PC is negative, that is to say, during this period, the capacitor will send the stored electric energy back to the power supply. The area surrounded by the positive and negative half cycle curves of instantaneous power is equal, which means that the energy absorbed by the capacitor from the power source is equal to the energy returned to the power source, that is:

純電容不消耗能量，它只與電源不斷地進行能量的交換。

Pure capacitance does not consume energy, it only exchanges energy with power supply continuously.

電容的平均功率為：

The average power of the capacitor is:

電容的平均功率計算公式

Calculation formula of average power of capacitor

平均功率為零只是說明電容不消耗有功功率，并不說明電容中沒有功率。電容與電源之間有能量交換，所以瞬時功率并不等于零。瞬時功率的大值UI的乘積稱為無功功率，用符號Qc表示，它反映了電容與電源交換能量的大規(guī)模。