Name: op amp stages in series
Uploaded: 2026-08-26T10:58:23.494Z
Duration: 1 min 16 s
Channel: JoVE

Gli amplificatori operazionali possono essere collegati in cascata, uno dopo l'altro in sequenza lineare, senza alterare le loro relazioni tra ingresso e uscita grazie alla loro resistenza di ingresso infinita e alla resistenza di uscita nulla.
In un sistema in cascata, ciascun amplificatore è noto come stadio, e l'uscita di un amplificatore pilota l'amplificatore successivo.
Il segnale in ingresso viene amplificato successivamente dal guadagno di ogni stadio, producendo un guadagno complessivo maggiore pari al prodotto dei guadagni di ciascun amplificatore.
Il guadagno totale viene distribuito tra più stadi, ciascuno con un guadagno inferiore rispetto a quello ottenibile con un singolo amplificatore operazionale. Poiché il prodotto guadagno-banda rimane costante per ogni amplificatore operazionale, tale distribuzione aumenta la banda passante di ciascuno stadio, determinando un incremento complessivo della banda passante.
Negli schemi televisivi, gli amplificatori RF accordati utilizzano op amp in cascata. Essi amplificano segnali deboli e migliorano l'adattamento dell'impedenza di ingresso e di uscita, fornendo segnali audio e video di alta qualità.
Il circuito operazionale in cascata deve essere progettato in modo che i guadagni individuali non saturino il segnale nelle varie stadi della cascata.

amplificatori operazionali in cascata

Cascaded Op Amps

Gli amplificatori operazionali (amplificatori operazionali) sono componenti elettronici versatili che possono essere collegati tra loro in cascata, uno dopo l'altro in una sequenza lineare. Questo collegamento a cascata è possibile grazie alla loro resistenza di ingresso infinita e alla resistenza di uscita pari a zero, che consente loro di mantenere le relazioni ingresso-uscita anche quando collegati in serie.

In un sistema in cascata, ciascun amplificatore operazionale viene definito stadio. L'output di uno stadio guida l'input dello stadio successivo. Quando il segnale di ingresso passa attraverso ciascuno stadio, viene amplificato dal guadagno di quello stadio. Il guadagno complessivo risultante del sistema in cascata è pari al prodotto dei guadagni di ciascuno stadio.

Questo approccio a cascata offre diversi vantaggi. Distribuendo il guadagno totale tra più stadi, ogni stadio ha un guadagno inferiore rispetto a quando viene utilizzato un singolo amplificatore operazionale. Tuttavia, poiché il prodotto guadagno-larghezza di banda rimane costante per ciascun amplificatore operazionale, la riduzione del guadagno in ogni fase aumenta effettivamente la larghezza di banda in quella fase. Ciò porta ad un aumento complessivo della larghezza di banda del sistema in cascata.

Gli amplificatori operazionali in cascata trovano ampio utilizzo negli amplificatori RF sintonizzati presenti nei circuiti televisivi. Questi amplificatori in cascata amplificano i segnali deboli e migliorano l'adattamento dell'impedenza in ingresso e in uscita, fornendo agli spettatori segnali audio e video di alta qualità.

Tuttavia, la progettazione di un circuito con amplificatore operazionale in cascata richiede un'attenta considerazione. I singoli guadagni devono essere impostati in modo tale da non saturare il segnale nei vari stadi della cascata. La saturazione del segnale può distorcere l'uscita, portando a scarse prestazioni.

Amplificatori operazionali in cascata

Gli amplificatori operazionali possono essere collegati in cascata, uno dopo l'altro in sequenza lineare senza alterare le loro relazioni di ingresso-uscita a causa della loro ...

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Education

Didattica

JoVE Core

Electrical Engineering

Ingegneria elettrica

Unit 1

Unità 1

Operational Amplifiers

Amplificatori Operazionali

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

op amp stages in series

Operational amplifiers can be connected in series as separate stages. This cascade works because op-amps have very high input resistance and very low output resistance. Those properties help each stage keep its input-output relationship while driving the next stage.

In a cascaded op-amp circuit, the output of one stage becomes the input of the next. Each stage adds gain to the signal as it passes through. The overall gain is the product of the gain of each stage.

This design can improve bandwidth because the total gain is shared across several stages. Since the gain-bandwidth product of an op-amp stays constant, a stage with less gain can have more bandwidth. As a result, the full cascaded system can achieve a wider bandwidth than a single high-gain stage.

Cascaded op-amps are used in tuned RF amplifiers, such as those in television circuits. They help amplify weak signals and improve impedance matching at the input and output. This supports better audio and video quality for viewers.

Design still matters when stages are linked this way. The gains must be chosen so the signal does not saturate in any stage. Saturation can distort the output and reduce performance.

Op Amp Stages in Series

operational amplifiers

Operational Amplifier Pinout and Signal Use

An operational amplifier, or op-amp, is a flexible circuit building block used in many electronic designs. It can act like a voltage-controlled voltage source, and it can also be used to create a voltage- or current-controlled current source. When resistors and capacitors are connected to its terminals, an op-amp can perform mathematical operations on signals. Op-amps are able to sum signals, amplify a signal, integrate it, or differentiate it. These features make them useful in practical...

characteristics of opamp

Op-Amp Gain, Feedback, and Saturation

An operational amplifier, or op-amp, is an electronic circuit component used with other circuit parts to carry out a signal-processing task. It is often described with an equivalent circuit model. In that model, the output section includes a voltage-controlled source in parallel with the output resistance, R o. The model also shows the input resistance, R i, which is the Thevenin equivalent resistance seen at the input terminals. The differential input voltage, v d, is the difference between...

design example: vintage mixing console

Op-Amp Preamp for a Vintage Console

A sound engineer designs an op-amp pre-amplifier for a vintage mixing console. The console’s output is too low for modern recording equipment, so the signal must be boosted before it can be used. The goal is to build a preamp that raises the audio level without changing the console’s character. The design must meet three clear requirements. It needs a gain of 10, an input impedance above 10 kilo-ohms so the console is not overloaded, and a frequency range that covers the full audio spectrum...

cascaded op amps

Operational amplifiers can be connected in series as separate stages. This cascade works because op-amps have very high input resistance and very low output resistance. Those properties help each stage keep its input-output relationship while driving the next stage. In a cascaded op-amp circuit, the output of one stage becomes the input of the next. Each stage adds gain to the signal as it passes through. The overall gain is the product of the gain of each stage. This design can improve...

inverting and non-inverting opamps

Op-Amp Gain: Inverting, Noninverting, Buffer

Operational amplifiers can be used as inverting, noninverting, and buffer amplifiers. In these circuits, the output voltage depends on the input voltage and the resistor setup around the op-amp. In an inverting amplifier, the input voltage is sent through a resistor to the inverting terminal. The non-inverting terminal is grounded, and a feedback resistor links the inverting terminal to the output. Using Kirchhoff's Current Law and an ideal op-amp model, the gain can be found. This circuit...

sum and difference opamps

Op-Amp Adders and Subtractors

Operational amplifiers can be wired to add or subtract signals. In these two op-amp setups, the summing amplifier combines several input signals into one output, while the difference amplifier compares two inputs and amplifies their difference. A summing amplifier is also called an adder. Input signals, such as audio signals, enter through input resistors. These resistors send currents through the feedback resistor, which produces an output voltage. Using Kirchhoff's current law and Ohm's Law,...

characteristics of practical op amps

Op Amp Noise Rejection and Buffering

Practical op amps are used to separate useful signals from unwanted noise. A difference amplifier should ideally amplify only the difference between two input signals. In real circuits, though, the output depends on both differential gain and common-mode gain. The common-mode rejection ratio, or CMRR, measures how well an op amp rejects common-mode signals. Common-mode signals are the same on both inputs. A higher CMRR helps an op amp ignore noise and amplify the wanted signal, such as music...

integrator and differentiator

Op-Amp Circuits in Cruise Control

Op-amp circuits are used in cruise control systems to help cars keep a constant speed. In these systems, operational amplifiers, or op-amps, can work as integrators and differentiators. Both circuits use resistors and capacitors, which makes them compact and cost-effective. An integrator circuit produces an output that is proportional to the integral of the input signal. It is made by replacing the feedback resistor in a standard inverting amplifier with a capacitor. The output and input...

instrumentation amplifier

ECG Signal Amplifier Design

An ECG signal amplifier helps an electrocardiography machine measure the heart’s electrical activity. ECG electrodes detect tiny voltage changes on the skin that come from depolarization of the heart muscle during each heartbeat. These signals are in the microvolt range, so they can be easily hidden by noise or interference. To solve this problem, ECG machines use an instrumentation amplifier. This amplifier boosts the ECG waveform while reducing common-mode noise, which is interference that...

key terms and concepts

Learn how op amp stages in series work, why gains multiply, and how cascading can widen bandwidth in RF amplifiers and TV circuits.

Op Amp Stages in Series | JoVE K12

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

Op Amp Stages in Series

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