Name: analyzing an op amp audio filter
Uploaded: 2024-04-11T12:48:50.000Z
Duration: 1 min 18 s
Channel: JoVE

En un sistema de audio, el circuito de filtro procesa la señal de audio amplificada de un amplificador, atenuando fuertemente los componentes de la señal con bajas frecuencias.
Considere el circuito de filtro más simple que consta de un amplificador operacional en una configuración inversa acoplado con las resistencias R1 y R2 y el condensador C1. ¿Cuál es la señal de salida resultante para una señal de entrada conocida?
La impedancia del condensador se calcula utilizando la frecuencia angular derivada de la expresión en el dominio del tiempo para el voltaje de entrada.
El circuito equivalente en el dominio de la frecuencia representa la señal de entrada en forma polar y las impedancias Z1 y Z2. La impedancia Z2 corresponde a la combinación en paralelo del condensador C1 y la resistencia R2.
Aplicando la ley de corriente de Kirchoff y la ley de Ohm en el nodo se obtiene una ecuación nodal para un amplificador operacional ideal. Esta ecuación, cuando se reorganiza, indica que la relación entre el voltaje de salida y el voltaje de entrada es igual a la relación negativa de las impedancias.
Al sustituir los valores conocidos y calculados en esta ecuación, el voltaje de salida se determina en forma polar, que luego se convierte en el dominio del tiempo.

circuitos de ca con amplificador operacional

Dentro de un sistema de audio, el circuito de filtro juega un papel fundamental en el procesamiento de la señal de audio amplificada de un amplificador. Su función principal es atenuar significativamente los componentes de la señal con frecuencias más bajas, dando forma así a la salida de audio. Se examinan las operaciones de este circuito, centrándose en la configuración del filtro fundamental. Esta configuración implica un amplificador operacional dispuesto en una configuración inversora acoplada con resistencias (R1 y R2) y un condensador (C1). <img alt="Figure1" src="/files/ftp_upload/15116/15116_PT_Figure_1.svg" style="text-align: center; height: 164px;"> Cuando nos enfrentamos a una señal de entrada conocida, el desafío radica en determinar la señal de salida resultante. El primer paso consiste en calcular la impedancia del condensador, que se logra empleando la frecuencia angular derivada de la expresión en el dominio del tiempo del voltaje de entrada. <img alt="Equation1" src="/files/ftp_upload/15116/15116_PT_Equation_1.svg" style="text-align: center; height: 36px;"> Como resultado, el análisis pasa al dominio de la frecuencia, donde la señal de entrada se representa en forma polar junto con los componentes de impedancia Z1 y Z2. Z2 se refiere explícitamente a la combinación en paralelo del condensador C1 y la resistencia R2. El núcleo del análisis se basa en aplicar la ley de corriente de Kirchhoff y la ley de Ohm en un nodo específico del circuito, formulando así una ecuación nodal para un amplificador operacional ideal. Esta ecuación, cuando se reorganiza, revela una idea crítica: la relación entre el voltaje de salida y la entrada es inversamente proporcional a la relación de impedancias. <img alt="Equation2" src="/files/ftp_upload/15116/15116_PT_Equation_2.svg" style="text-align: center; height: 36px;"> Los valores conocidos y calculados se sustituyen hábilmente en esta ecuación para revelar el voltaje de salida en forma polar. El resultado, que representa el voltaje de salida, se puede transformar al dominio del tiempo, proporcionando una comprensión integral de la respuesta del circuito de filtro a la señal de entrada. Para el análisis, a menudo se suponen propiedades ideales del amplificador operacional, incluido el principio de que no ingresa corriente a ninguno de sus terminales de entrada y que el voltaje a través de sus terminales de entrada permanece cero.

Circuitos de CA con amplificador operacional

En un sistema de audio, el circuito de filtro procesa la señal de audio amplificada de un amplificador, atenuando fuertemente los componentes de la señal ...

Education

Educación

JoVE Core

Electrical Engineering

Ingeniería Eléctrica

Unit 1

Unidad 1

AC Circuit Analysis

Análisis de circuitos de corriente alterna (CA)

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

Op Amp AC Circuits

analyzing an op amp audio filter

An op amp audio filter shapes an amplified sound signal by strongly reducing the lower-frequency parts. In this circuit, the focus is on a basic filter setup used after an amplifier in an audio system. The filter uses an operational amplifier in an inverting arrangement with resistors R1 and R2 and a capacitor C1.

The analysis starts with a known input signal and asks for the output signal. To solve it, the capacitor impedance is found first. That requires the angular frequency from the time-domain form of the input voltage, so the work moves into the frequency domain.

In the frequency domain, the input signal is written in polar form. The impedances Z1 and Z2 are then used, with Z2 representing the parallel combination of capacitor C1 and resistor R2. At the same time, the ideal op amp assumptions are used. No current enters either input terminal, and the voltage across the input terminals is zero.

The final step is applying Kirchhoff's current law and Ohm's law at one node in the circuit. This creates a nodal equation for the ideal op amp. When that equation is rearranged, the output-to-input voltage ratio is shown to be inversely proportional to the impedance ratio. The known values are then substituted to find the output voltage in polar form, and that result can be converted back to the time domain for a full description of the filter response.

Analyzing an Op Amp Audio Filter

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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

Analyzing an Op Amp Audio Filter

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