Capacitive Voltage Divider

在这篇文章中，我们了解了电容电压分隔电路如何通过公式和解决的示例在电子电路中运行。

By: Dhrubajyoti Biswas

What is a Voltage Divider Network

Talking about a voltage divider circuit, it is important to note that voltage in divider circuit gets equally distributed among all the existing components associated with the network, although the capacity may vary based upon the constitution of the components.

电压分隔电路可以由反应性组件甚至固定电阻构建。

However, when comparing to capacitive voltage dividers, the resistive dividers remain unaffected with the change of frequency in supply.

本文的目的是提供对电容电压隔板的详细理解。但是，要获得更多的洞察力，对于细节电容电抗及其对电容器的影响至关重要。

电容器由两个导电板制成，彼此平行放置，并与绝缘体分离。这两个板有一个正（+）和另一个负（ - ）电荷。

当电容器通过直流电流充分充电时，介电（通常引用的绝缘子）堵塞了整个板上的电流流。

Another important characteristic of a capacitor in comparison to a resistor is: A capacitor stores energy on the conductive plates during charge, which the resistor does not, as it always tends to release out excess energy as heat.

但是电容器存储的能量传递给在放电过程中与之相连的电路。

电容器存储电荷的此功能称为电抗，进一步称为电容电抗[XC]，其ohm是电抗测量值的标准单位。

放电电容器连接到直流电源时，电抗在初始阶段保持较低。

A substantial part of the current flows via the capacitor for a short span, which force the conductive plates get charged rapidly, and this eventually inhibits any further passage of current.

How Capacitor Blocks DC?

In a resistor, capacitor series network when the time period reaches a magnitude of 5RC, the conductive plates of the capacitor get fully charged, which signifies the charge received by the capacitor to be equal to the voltage supply, which stops any further current flow.

此外，在DC电压的影响下，电容器在这种情况下的电抗达到了最大状态[Mega-Ohms]。

交流电源的电容器

关于使用备用电流[AC]给电容器充电，其中AC电流的流动始终交替极化，接收流动的电容器会经受恒定的充电和在其板上的恒定充电和放电。

现在，如果我们有恒定的电流流量，那么我们还需要确定电抗值以限制流量。

Factors to determine value of capacitive resistance

If we take a look back on the capacitance we will find that the amount of charge on the conductive plates of a capacitor is proportional to the value of the capacitance and the voltage.

现在，当电容器从交流输入中获取电流流量时，电压电源会经历其值的恒定变化，该值总是会过于按比例地更改板的值。

Now let’s consider a situation where a capacitor contains higher value of capacitance.

在这种情况下，电阻r会消耗更多时间给电容器τ= rc充电。这意味着，如果充电电流在更长的时间内流动，则电抗记录较小的值XC，具体取决于指定的频率。

如果电容器中的电容值较小，则相同，为了给电容器充电，则需要较短的RC时间。

此较短的时间导致较短时间的电流流动，从而导致相对较小的电抗值xc。

Therefore, it is evident that with higher currents the value of the reactance remains small and vice versa.

因此，电容电抗总是与电容器的电容值成反比。

XC ∝ -1 C.

重要的是要注意，电容不是分析电容电抗的唯一因素。

With a low frequency of the AC voltage applied, the reactance gets more time develop based upon the allocated RC time constant. Further, it also blocks the current, indicating higher value of reactance.

Similarly, if the frequency applied is high, the reactance allows lesser time cycle for charging and discharging process to occur.

Moreover, it also receives higher current flow during the process, which leads to lower reactance.

So this proves that the impedance (AC reactance) of a capacitor and its magnitude is dependent on the frequency. Therefore, higher frequency results in lower reactance and vice versa, and thus it can be concluded that Capacitive Reactance Xc is inversely proportional to the frequency and capacitance.

可以用以下方程来概括的电容电抗理论：

Xc = 1/2πfC

在哪里：

· Xc = Capacitive Reactance in Ohms, (Ω)


·π（pi）= 3.142（或22÷7）的数字常数


·=赫兹的频率，（Hz）


·c =法拉德的电容，（f）

Capacitive Voltage Divider

本节将旨在提供有关供应频率如何影响背部或串联连接的两个电容器的详细说明，更好地称为电容电压分隔电路。

Capacitive Voltage Divider Circuit

为了说明电容电压分隔器功能，让我们参考上面的电路。在这里，C1和C2串联并连接到10伏的交流电源。串联两个电容器都收到相同的费用，q。

However, the voltage will remain different and it is also dependent on the value of capacitance V = Q/C.

Considering Figure 1.0, the calculation of voltage across the capacitor can be determined through different ways.

一种选择是找出总电路阻抗和电路电流，即跟踪每个电容器上电容电抗的值，然后计算跨它们的电压下降。例如：

EXAMPLE 1

如图1.0，分别为10UF和20UF的C1和C2，在正弦电压为10伏RMS @ 80Hz的情况下计算在电容器上发生的RMS电压降。

C1 10uF Capacitor
xc1 = 1/2πfc= 1/2πx 80 x 10uf x 10-6 = 200欧姆
C2 = 20uF capacitor
Xc1 = 1/2πfC = 1/2π x 8000 x 22uF x 10-6 = 90
Ohm

总电容电抗

XC（Total）= XC1 + XC2 =200Ω +90Ω=290Ω
CT =（C1 X C2） /（C1 + C2）= 10UF X 22UF / 10UF + 22UF = 6.88UF
xc = 1/2πfct= 1/1/2πx 80 x 6.88uf =290Ω

Current in the circuit

i = e / xc = 10V /290Ω

电容器的两个电压均降低。在这里，电容电压分隔器计算为：

Vc1 = I x Xc1 = 34.5mA x 200Ω = 6.9V
Vc2 = I x Xc2 = 34.5mA x 90Ω = 3.1V

如果电容器的值有所不同，则较小的值电容器可以与大值1相比充电到更高的电压。

In Example 1, the voltage charge recorded is 6.9 & 3.1 for C1 and C2 respectively. Now since the calculation is based on Kirchoff’s theory of voltage, therefore the total voltage drops for individual capacitor equals to the supply voltage value.

NOTE:

The voltage drop ratio for the two capacitors that is connected to series capacitive voltage divider circuit always remains same even if there is a frequency in supply.

Therefore as per Example 1, 6.9 and 3.1 volts are the same, even if the supply frequency is maximized from 80 to 800Hz.

EXAMPLE 2

How to find the capacitor voltage drop using the same capacitors used in Example 1?

xc1 = 1/2πfc= 1/2πx 8000 x 10uf = 2欧姆

xc1 = 1/2πfc= 1/2πx 8000 x 22uf = 0.9 ohm

I = V/Xc(total) = 10/2.9 = 3.45 Amps

Therefore, Vc1 = I x Xc1 = 3.45A x 2Ω = 6.9V

和，vc2 = i x xc2 = 3.45a x0.9Ω= 3.1V

由于两个电容器的电压比保持不变，随着供应频率的增加，其影响以降低的组合电容电抗性以及总电路阻抗的形式看到。

降低的阻抗会导致较高的电流流动，例如，80Hz的电路电流约为34.5mA，而在8kHz时，电流电源可能增加10倍，约为3.45a。

因此可以得出结论，通过电容电压分隔器的电流流与频率成正比。

如上所述，涉及连接的一系列电容器的电容隔板，它们都降低了交流电压。

为了找出正确的电压滴，电容隔板的值是电容器的电容电抗值。

因此，它不能用作DC电压的分隔线，因为在DC中，电容器停止并阻止电流，这会导致零电流流量。

分隔线可以在供应频率驱动的情况下使用。

从手指扫描装置到COLPITTS振荡器，电容电压隔板的电子使用广泛。它也是广泛的优选，因为采用电容电压分隔器可降低电流电流的廉价替代品。