What are the impedance characteristics of series parallel resonant circuits? Wuhan UHV specializes in the production of series resonance, with a wide range of product selection and professional electrical testing. To find series resonance, choose Wuhan UHV.
There are two forms of resonant circuits: parallel circuits and series circuits. The impedance characteristics of series resonant and parallel resonant circuits are influenced by factors such as resonant impedance, resonant characteristic impedance, and resonant quality. However, in reality, the characteristic impedance of series parallel resonant circuits is determined by the resonant circuit. So what are the impedance characteristics of a resonant circuit, and what are the characteristics and differences between the impedance of a series resonant circuit and a parallel resonant circuit?
Impedance characteristics of series parallel resonant circuits
1. Impedance characteristics of a series resonant circuit: The thermal properties that vary with the frequency of the input signal and the output current of the circuit become the frequency selective characteristics of the circuit. When a series resonant circuit occurs, the current flowing out of the circuit is maximized due to the minimum impedance of the circuit.
a. When the impedance characteristic circuit resonates, the inductive impedance and capacitive impedance of the circuit are equal and cancel each other out, resulting in the minimum impedance of the circuit and pure resistance;
b. When the circuit is detuned, the impedance of the series resonant circuit increases and the phase value increases. When W>W0, the impedance of the series circuit is inductive; When W>W0, the impedance of the series circuit is capacitive.
2. Impedance characteristics of parallel resonant circuit:
The characteristic of a parallel resonant circuit is that during resonance, the circuit impedance is the highest and pure resistance, that is, Z0=R0=; The resonant impedance is Q times the inductive or capacitive impedance, i.e. Z0=Q ω 0L=Q/ω 0C.
When the current is constant, the voltage across the inductor or capacitor is maximum. If it deviates from the resonant frequency, the circuit impedance and voltage will significantly decrease.
3. Comparison of series parallel circuits
Phase frequency characteristics: The phase frequency characteristics of a series circuit are positive covariance, while those of a parallel circuit are negative slope, with a maximum phase shift of ± 90
4. In practical applications, a series circuit is suitable for connecting a signal source and a load in series, thereby effectively delivering signal current to the load; Parallel circuits are suitable for connecting signal sources and loads in parallel, allowing the signal to obtain the maximum voltage amplitude on the load
The resonant circuit belongs to a passive filtering network, and its function is
Frequency selective filtering: selecting useful frequency components from the input signal and suppressing useless frequency components or noise;
Impedance transformation circuit and matching circuit;
Implementing frequency amplitude and phase transformation: converting frequency changes into amplitude or phase changes; It will be discussed in frequency modulation.
The analysis of parallel resonant impedance characteristics requires dividing the input signal frequency into multiple scenarios:
1. The input signal frequency is equal to the resonant frequency fo
When the signal frequency is equal to the resonant frequency fo of the LC series resonant circuit, the circuit undergoes series resonance, and the impedance of the series resonant circuit is the smallest and purely resistive (not capacitive or inductive), with a value of (purely resistive).
When the signal frequency deviates from the resonant frequency of the LC resonant circuit, the impedance of the circuit increases, and the larger the frequency deviation, the larger the impedance of the circuit, which is exactly opposite to the LC parallel resonant circuit.
Remember: the impedance of the circuit is minimized during series resonance.
2. The input signal frequency is higher than the resonant frequency fo
When the input signal frequency is higher than the resonant frequency, the LC series resonant circuit is inductive, equivalent to an inductor