主要区别–串联与并联谐振

谐振是一种发生在由电容器和电感组成的电路中的现象。当电路的电容阻抗等于电感阻抗时，就会发生谐振。根据电容器、电感器和电阻器的布置，实现谐振的条件因不同类型的电路而异。串联谐振是指电容器和电感器串联的电路中发生的谐振，而并联谐振是指电容器和电感器并联的电路中发生的谐振。串联谐振和并联谐振的主要区别在于，串联谐振发生在元件排列产生最小阻抗时，而并联谐振发生在元件排列产生最大阻抗时。

什么是串联谐振(series resonance)？

在上一篇关于阻抗和电阻之间的差异的文章中，我们研究了一个串联RLC电路。在这里，我们分析了以下电路：

An AC circuit containing a resistor, a capacitor and an inductor

To recap, the capacitor has a capacitive reactance ( ) given by  . The inductor has an inductive reactance ( ) given by  . We saw that the magnitude of the total impedance can be given by  .

The current through the circuit is given by  . If we change the frequency of the AC current, we can change both  and  . As these values change, the total impedance of the circuit will also change. This would mean that the size of the current through the circuit would change as well. In particular, when we look at the equation for impedance, we can see that when  , the impedance is minimum ( ). At this value, therefore, the current through the circuit would be at a maximum. The graph below depicts how the current through the circuit changes, as we change the frequency of the AC current.

A graph of current vs. frequency for a series RLC resonant circuit

At the resonant frequency,  . This means that . We can solve this to show that the resonance frequency  is given by:

什么是平行共振(parallel resonance)？

并联谐振发生在电感和电容并联的电路中，如下所示：

A parallel RLC circuit

Since impedances do not add up in the same way in parallel circuits as they do in series circuits, a quantity called admittance ( ) is used to describe parallel resonance circuits. Admittance is simply the reciprocal of impedance:

The conductance ( ) is given by the reciprocal of resistance:

For parallel circuits, susceptance is the quantity ****ogous to reactance in series circuits. Capacitive susceptance ( ) is given by  . Inductive susceptance ( ) is given by  . The admittance can be expressed using these quantities:

For parallel RLC circuits, resonance occurs when  . Here,  and solving for the resonance frequency  we once again find that:

当并联RLC电路谐振时，其上的电流将取最小值。这是因为此时电路的阻抗处于最大值。

系列(series)和平行共振(parallel resonance)的区别

阻抗

在谐振频率下，串联RLC电路的阻抗最小，而并联RLC电路的阻抗最大。

现在的

在谐振频率下，串联RLC电路的电流最大，而并联RLC电路的阻抗最小。