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

加算アンプ(加算器)は、オペアンプを使用して複数の入力信号を1つの出力に結合します。
逆に、ディファレンスアンプ(サブトラクタ)は、2つの入力信号の差を増幅します。
オペアンプを備えたオーディオミキサー回路を考えてみましょう。
オーディオ信号が入力チャンネルに供給されると、入力抵抗はフィードバック抵抗を流れる電流を生成し、出力電圧を生成します。
オペアンプの入力ノードでキルヒホッフの電流法則をオームの法則と組み合わせて使用すると、結果として得られる出力電圧は入力信号の加重和に比例します。
基本的な差動オペアンプ回路は、このミックスのオーディオトラックノイズを部分的に低減できます。
反転ノードと非反転ノードにKCLを適用すると、2つの方程式が得られます。両方のノード間で電圧が等しい場合、出力電圧式が得られます。
ディファレンスアンプは、抵抗比が特定の条件を満たす場合にのみ、両方の入力に共通の信号を無効化できます。その結果、差動出力が得られます。
抵抗R2がR1に等しく、R3がR4に等しい場合、ディファレンスアンプは減算器として機能します。

オペアンプの和と差

オペアンプ (オペアンプ) は、様々な信号処理タスクにも適応できる多用途デバイスです。これに関連して、加算アンプと差動アンプという 2 つの特定のオペアンプ構成について説明します。

加算アンプまたは加算器は、オペアンプを利用して複数の入力信号を 1 つの出力信号に結合するデバイスです。オーディオ信号が入力チャンネルに入力されると、入力抵抗がフィードバック抵抗を流れる電流を開始し、出力電圧が発生します。キルヒホッフの電流法則とオームの法則を適用すると、出力電圧は入力信号の加重和となります。この基本的な差動オペアンプ回路は、オーディオ ミキサー アプリケーションでオーディオ トラックのノイズを軽減する役割を果たします。

<img alt="Equation1" src="/files/ftp_upload/15079/15079_PT_Equation_1.svg" style="text-align: center; height: 32px;">

逆に、差分アンプは減算器と呼ばれることが多く、2 つの入力信号間の差異を増幅します。キルヒホッフの電流法則を反転ノードと非反転ノードに適用することにより、2 つのFigureが確立されます。出力電圧式は、両方のノード間に等しい電圧が存在する場合に導出されます。ただし、差動アンプが入力間の共通信号を無効にするためには、比抵抗比の条件が満たされる必要があります。対応するブランチの抵抗が等しい場合、差動アンプは減算器として機能します。

<img alt="Equation2" src="/files/ftp_upload/15079/15079_PT_Equation_2.svg" style="text-align: center; height: 32px;">

要約すると、オペアンプは増幅と加算および減算タスクを実行する機能を提供します。加算アンプは入力を重み付けされた合計に結合します。差動アンプは 2 つの入力間の差を増幅し、共通信号を除去します。これらの構成を理解することで、信号処理や回路設計における多くの実際的な応用への扉が開かれます。

加算アンプ(加算器)は、オペアンプを使用して複数の入力信号を1つの出力に結合します。
逆に言えば、違いは...

Education

JoVE Core

Electrical Engineering

電気工学

Unit 1

ユニット1

Operational Amplifiers

演算増幅器（オペアンプ）

KEY TERMS AND CONCEPTS

主要用語と概念

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 電気工学 は、電気回路の基本概念と回路解析テクニックを網羅したアニメーションビデオシリーズです。オペアンプと回路変換および 1 次・ 2 次回路の概念を網羅しています。実験を撮影した実写動画では、設計例や現代社会での応用が含まれており、複雑な概念も分かりやすく学習いただけます。

electrical engineering

Op-Amp Adders and Subtractors

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