Name: op-amp adders and subtractors
Uploaded: 2024-04-11T12:48:35.000Z
Duration: 1 min 22 s
Channel: JoVE

Un amplificatore sommatore, o sommatore, utilizza un amplificatore operazionale per combinare più segnali di ingresso in un'unica uscita.
Al contrario, un amplificatore di differenza, o un sottrartore, amplifica la differenza tra due segnali di ingresso.
Considera un circuito mixer audio con un amplificatore operazionale.
Quando i segnali audio vengono immessi nei canali di ingresso, i resistori di ingresso generano correnti che fluiscono attraverso i resistori di retroazione, producendo una tensione di uscita.
Utilizzando la legge di corrente di Kirchhoff al nodo di ingresso dell'amplificatore operazionale in combinazione con la legge di Ohm, la tensione di uscita risultante è proporzionale alla somma ponderata dei segnali di ingresso.
Un circuito di amplificazione operazionale differenziale di base può ridurre parzialmente il rumore della traccia audio in questo mix.
L'applicazione di KCL ai nodi invertenti e non invertenti produce due equazioni. Con tensioni uguali su entrambi i nodi, si ottiene un'espressione della tensione di uscita.
L'amplificatore differenziale può annullare i segnali comuni a entrambi gli ingressi solo quando i rapporti di resistenza soddisfano determinate condizioni. Di conseguenza, si ottiene un'uscita differenziale.
Quando la resistenza R2 è uguale a R1 e R3 è uguale a R4, l'amplificatore differenziale funziona come un sottrarre.

somma e differenza degli amplificatori operazionali

Gli amplificatori operazionali (amplificatori operazionali) sono dispositivi versatili che vanno oltre l'amplificazione. In questo contesto, vengono esplorate due specifiche configurazioni di amplificatori operazionali: gli amplificatori sommatori e differenziali.

Un amplificatore sommatore, o sommatore, utilizza un amplificatore operazionale per unire più segnali di ingresso in un singolo segnale di uscita. Quando i segnali audio vengono introdotti nei canali di ingresso, i resistori di ingresso avviano correnti che attraversano i resistori di feedback, risultando in una tensione di uscita. Applicando la legge attuale di Kirchhoff e la legge di Ohm, la tensione di uscita diventa una somma ponderata dei segnali di ingresso. Questo circuito differenziale di base dell'amplificatore operazionale svolge un ruolo nel mitigare il rumore della traccia audio nelle applicazioni di mixer audio.

<img alt="Equation1" src="/files/ftp_upload/15079/15079_PT_Equation_1.svg" style="text-align: center; height: 32px;">

Al contrario, un amplificatore differenziale, spesso chiamato sottrattore, amplifica la disparità tra due segnali di ingresso. Due equazioni vengono stabilite applicando la legge attuale di Kirchhoff ai nodi invertenti e non invertenti. Un'espressione della tensione di uscita viene derivata quando esistono tensioni uguali su entrambi i nodi. Tuttavia, devono essere soddisfatte condizioni specifiche del rapporto di resistenza affinché l'amplificatore differenziale annulli i segnali comuni tra gli ingressi. Quando le resistenze nei rami corrispondenti sono uguali, l'amplificatore differenziale funziona come sottrattore.

<img alt="Equation2" src="/files/ftp_upload/15079/15079_PT_Equation_2.svg" style="text-align: center; height: 32px;">

In sintesi, gli amplificatori operazionali offrono amplificazione e la capacità di eseguire attività di addizione e sottrazione. L'amplificatore sommatore combina gli ingressi in una somma ponderata. L'amplificatore differenziale amplifica la disparità tra due ingressi e rifiuta i segnali comuni. La comprensione di queste configurazioni apre le porte a molte applicazioni pratiche nell'elaborazione dei segnali e nella progettazione di circuiti.

Somma e differenza degli amplificatori operazionali

Un amplificatore sommatore, o sommatore, utilizza un amplificatore operazionale per combinare più segnali di ingresso in un'unica uscita.
Al contrario, una differenza ...

Education

Didattica

JoVE Core

Electrical Engineering

Ingegneria elettrica

Unit 1

Unità 1

Operational Amplifiers

Amplificatori Operazionali

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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, the output becomes a weighted sum of the inputs. This type of circuit can help reduce noise in audio mixer applications.

A difference amplifier is also called a subtractor. It amplifies the difference between two input signals. To describe its behavior, two equations are written by applying Kirchhoff's current law at the inverting and non-inverting nodes. When equal voltages appear across both nodes, an output voltage expression can be derived. Specific resistance ratios must be met for the circuit to cancel signals that are common to both inputs. When the resistances in the matching branches are equal, the difference amplifier works as a subtractor.

These op-amp circuits show that operational amplifiers do more than boost signals. They can perform addition and subtraction in circuit design. The summing amplifier creates a weighted total of multiple inputs, and the difference amplifier rejects common signals while highlighting the difference between two inputs. These ideas are useful in signal processing and many practical electronics applications.

Op-Amp Adders and Subtractors

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...

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...

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...

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

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...

cascaded op amps

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...

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 adders and subtractors combine signals, compare two inputs, and use resistor ratios to create weighted sums and signal rejection.

Op-Amp Adders and Subtractors | 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 Adders and Subtractors

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