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

Nei circuiti CA, gli elementi passivi - il resistore, l'induttore e il condensatore - sono caratterizzati dalla tensione e dalla corrente del fasore.
L'impedenza è il rapporto tra la tensione del fasore e la corrente e rappresenta la resistenza al flusso di corrente sinusoidale in un circuito CA.
Per le sorgenti CC con frequenza zero, l'induttore funziona come un cortocircuito con impedenza zero, mentre il condensatore funziona come un circuito aperto con impedenza infinita.
Tuttavia, alle alte frequenze, l'induttore agisce come un circuito aperto e il condensatore diventa un cortocircuito.
L'impedenza è una grandezza complessa che può essere espressa in forma rettangolare, dove la parte reale denota la resistenza e la parte immaginaria rappresenta la reattanza.
La reattanza può essere positiva o negativa. Una reattanza positiva implica un'impedenza induttiva, in cui la corrente è in ritardo rispetto alla tensione. Al contrario, una reattanza negativa indica un'impedenza capacitiva, in cui la corrente guida la tensione.
Nella forma polare, l'impedenza può essere caratterizzata dalla sua grandezza e dall'angolo di fase.
L'ammissione, il reciproco dell'impedenza, può essere espressa anche in forma rettangolare, dove le componenti reale e immaginaria rappresentano rispettivamente la conduttanza e la suscettibilità.

impedenza e ammettenza

Impedances and Admittance

Nel campo dei circuiti CA, gli elementi dei circuiti passivi come resistori, induttori e condensatori, assumono un carattere diverso se caratterizzati da tensione e corrente del fasore. Il loro comportamento è espresso attraverso l'impedenza, un concetto vitale nell'analisi del circuito CA.

L'impedenza è una misura della resistenza al flusso di corrente sinusoidale in un circuito CA. A differenza del loro comportamento nei circuiti CC, dove gli induttori appaiono come cortocircuiti e i condensatori come circuiti aperti, il comportamento di questi componenti nei circuiti CA dipende dalla frequenza. Ad alte frequenze, gli induttori si comportano come circuiti aperti, mentre i condensatori diventano cortocircuiti.

L'impedenza è una quantità complessa con una parte reale che indica la resistenza e una parte immaginaria che rappresenta la reattanza. La reattanza può essere positiva o negativa, indicando un'impedenza induttiva quando la corrente resta indietro rispetto alla tensione e un'impedenza capacitiva quando la corrente precede la tensione. L'impedenza può anche essere rappresentata in forma polare, evidenziandone l'ampiezza e l'angolo di 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;">

Il reciproco dell'impedenza è l'ammettenza, che si misura in Siemens (S). L'ammettenza rappresenta la facilità con cui la corrente scorre attraverso un circuito. Comprende conduttanza (parte reale) e suscettanza (parte immaginaria). L'ammettenza, come l'impedenza, è uno strumento prezioso nell'analisi dei circuiti CA, poiché consente agli ingegneri di comprendere e manipolare i circuiti elettrici che funzionano in condizioni sinusoidali.

Impedenza e Ammettenza

Nei circuiti CA, gli elementi passivi - il resistore, l'induttore e il condensatore - sono caratterizzati dalla tensione e dalla corrente del fasore.
L'impedenza è ...

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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.

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AC Circuit Response: Impedance and Admittance

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