Name: ac circuit response: impedance and admittance
Uploaded: 2024-04-11T12:48:49.000Z
Duration: 1 min 23 s
Channel: JoVE

Nos circuitos CA, os elementos passivos - o resistor, o indutor e o capacitor - são caracterizados pela tensão e corrente fasor.
A impedância é a razão entre a tensão fasorial e a corrente e representa a resistência ao fluxo de corrente senoidal em um circuito CA.
Para fontes CC com frequência zero, o indutor opera como um curto-circuito com impedância zero, enquanto o capacitor funciona como um circuito aberto com impedância infinita.
No entanto, em altas frequências, o indutor atua como um circuito aberto e o capacitor se torna um curto-circuito.
A impedância é uma grandeza complexa que pode ser expressa na forma retangular, onde a parte real denota a resistência e a parte imaginária representa a reatância.
A reatância pode ser positiva ou negativa. Uma reatância positiva implica impedância indutiva, onde a corrente fica atrás da tensão. Por outro lado, uma reatância negativa significa impedância capacitiva, onde a corrente conduz a tensão.
Na forma polar, a impedância pode ser caracterizada por sua magnitude e ângulo de fase.
A admitância, o recíproco da impedância, também pode ser expresso na forma retangular, onde os componentes real e imaginário representam a condutância e a suscetibilidade, respectivamente.

impedância e admitância

Impedances and Admittance

No domínio dos circuitos AC, os elementos do circuito passivo, como resistores, indutores e capacitores, assumem um caráter diferente quando caracterizados pela tensão e corrente dos fasores. Seu comportamento é expresso através da impedância, um conceito vital na análise de circuitos AC.

Impedância é uma medida de resistência ao fluxo de corrente senoidal em um circuito AC. Ao contrário do seu comportamento em circuitos DC, onde os indutores aparecem como curtos-circuitos e os condensadores como circuitos abertos, o comportamento destes componentes em circuitos AC depende da frequência. Em altas frequências, os indutores atuam como circuitos abertos, enquanto os capacitores tornam-se curtos-circuitos.

A impedância é uma quantidade complexa com uma parte real denotando resistência e uma parte imaginária representando a reatância. A reatância pode ser positiva ou negativa, indicando impedância indutiva quando a corrente está atrasada em relação à tensão e impedância capacitiva quando a corrente está à frente da tensão. A impedância também pode ser representada na forma polar, destacando sua magnitude e ângulo de fase.

<img alt="Equation1" src="/files/ftp_upload/15109/15109_PT_Equation_1v2.svg" style="text-align: center; height: 18px;" />

<img alt="Equation2" src="/files/ftp_upload/15109/15109_PT_Equation_2.svg" style="text-align: center; height: 15px;" />

O recíproco da impedância é a admitância, que é medida em Siemens (S). A admitância representa a facilidade com que a corrente flui através de um circuito. Compreende condutância (parte real) e susceptância (parte imaginária). A admitância, assim como a impedância, é uma ferramenta valiosa na análise de circuitos AC, permitindo aos engenheiros compreender e manipular circuitos elétricos operando sob condições senoidais.

Impedância e Admitância

Nos circuitos CA, os elementos passivos - o resistor, o indutor e o capacitor - são caracterizados pela tensão e corrente fasor.
A impedância é ...

Education

JoVE Core

Electrical Engineering

Engenharia Elétrica

Unit 1

Unidade 1

AC Circuit Analysis

Análise de Circuitos CA

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

ac circuit response: impedance and admittance

AC circuit response changes with frequency, and impedance describes how resistors, inductors, and capacitors affect sinusoidal current flow. In phasor form, voltage and current are used to show this behavior in a clear way. Impedance is a key idea in AC circuit analysis because it measures opposition to current in an alternating circuit.

These components behave differently in AC than in DC. In DC circuits, inductors act like short circuits and capacitors act like open circuits. In AC circuits, their behavior depends on frequency. At high frequencies, inductors act like open circuits, while capacitors become short circuits.

Impedance is a complex quantity. Its real part is resistance, and its imaginary part is reactance. Reactance can be positive or negative. Positive reactance shows inductive impedance, where current lags behind voltage. Negative reactance shows capacitive impedance, where current leads voltage.

Impedance can also be written in polar form. This form shows both magnitude and phase angle. The reciprocal of impedance is admittance, which is measured in Siemens, or S. Admittance shows how easily current flows through a circuit.

Admittance also has two parts. Its real part is conductance, and its imaginary part is susceptance. Like impedance, admittance helps engineers analyze AC circuits under sinusoidal conditions. It gives another useful way to study and shape circuit behavior.

AC Circuit Response: Impedance and Admittance

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Learn how impedance and admittance describe AC circuit behavior in resistors, inductors, and capacitors, including reactance, phase, and frequency effects.

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JoVE Core Electrical Engineering offers easy-to-understand animated videos that cover fundamental concepts of electric circuits along with circuit analysis techniques. It incorporates first-order and second-order circuits using operational amplifiers and circuit transformation concepts. The inclusion of practical design examples and real-world applications through scientist-in-action videos adds significant educational value, making complex concepts accessible.

electrical engineering

AC Circuit Response: Impedance and Admittance

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