We are Apogeeweb Semiconductor Electronic

WELCOME TO OUR BLOG

Home arrow Amplifiers arrow 20 Formulas for Operational Amplifier Circuit Design

arrow left

arrow right

20 Formulas for Operational Amplifier Circuit Design

Author: Apogeeweb Date: 19 Sep 2019  5373

basic amp circuit

Ⅰ Introduction

Although there are many types of operational amplifiers, different amplifier circuits are suitable for interfacing with different types of sensors, but most complex amplifiers are built by combining operational amplifiers. In order to get good amplication effect, it is necessary to design the circuit of the amplifier. This paper will introduce 20 opamp formulas as a design reference.

Op Amp Formulas For Voltage Calculation

Catalog

Ⅰ Introduction

Ⅱ Operational Amplifier Formulas


Ⅱ Operational Amplifier Formulas

In almost cases today, op amps are configured in different ways using a feedback network to “calculate” the input signal. There are 20 formulas used to calculate.

Figure 1. Voltage Follower

Note: Buffer High Impedance Signal and Low Impedance Load

 

Figure 2. In-phase Op Amp

Note: In-phase Signal Amplification

 

Figure 3. Reversed-phase Op Amp

Note: Amplify and Invert Input

 

Voltage Subtractor, Differential Amplifier Circuit

Figure 4. Voltage Subtractor, Differential Amplifier

Note: Amplify the voltage difference and suppress the common - mode voltage

 

Voltage Adder circuit

Figure 5. Voltage Adder

Note: Summation of Adding Voltage Values

 

As a Low-pass Filter, Integrator

Figure 6. Low-pass Filter, Integrator

Note: Limit Signal Bandwidth

 

High-pass Filter, Differentiator.png

Figure 7. High-pass Filter, Differentiator

Note: Eliminate DC, Amplify AC Signal

 

Differential Amplifier

Figure 8. Differential Amplifier

Note: Drive Differential Signal to Analog-to-Digital Converter From A Differential or Single-ended Signal Source

 

Instrumentation Amplifier

Figure 9. Instrumentation Amplifier

Note: Amplify the Low Level Difference Signal and Suppress the Common Mode Signal

 

Single State Op Amp Noise

Figure 10. Single State Op Amp Noise

Note: RTO NOISE=NG×RTI NOISE

     RTI=Converted to the Input

RTO=Converted to the Output

 

Decibel Formula (equivalent impedance)

 

Johnson-Nyquist Noise

Johnson-Nyquist Noise Formula

 

 

Ohm's Law (DC circuit)

 

Closed-loop Frequency Response (voltage feedback amplifier)

Figure 11. Closed-loop Frequency Response (voltage feedback amplifier)

 

resistance formulas.png

Resistance Formulas

 

Reactance Formulas

 

Transformer (step-up or step-down ratio)

 

Impedance Formulas (in series)

Note: RL in series

RC in series

LC in series

RLC in series 

 

Voltage and Impedance Formulas (parallel connection)

 

Frequently Asked Questions about Operational Amplifier Circuit

1. How do you make an op amp circuit?

2. What is amplifier with example?
Amplifiers are usually designed to function well in a specific application, for example: radio and television transmitters and receivers, high-fidelity ("hi-fi") stereo equipment, microcomputers and other digital equipment, and guitar and other instrument amplifiers.

 

3. Why do op amps have two inputs?
Operational amplifiers have two power supply rails because they usually need to swing bipolar - output voltages that go either positive or negative in response to the normal range of input signals. ... Without the dual supplies the output signal would clip at the ground potential.

 

4. Which type of amplifier is best?
Class “A” amplifiers are considered the best class of amplifier design due mainly to their excellent linearity, high gain and low signal distortion levels when designed correctly.

 

5. Are op amps AC or DC?
The basic Op-amp construction is of a 3-terminal device, with 2-inputs and 1-output, (excluding power connections). An Operational Amplifier operates from either a dual positive ( +V ) and an corresponding negative ( -V ) supply, or they can operate from a single DC supply voltage.

 

6. Can op amp amplify both AC and DC?
Infinite – An ideal operational amplifier has an infinite frequency response and can amplify any frequency signal from DC to the highest AC frequencies so it is therefore assumed to have an infinite bandwidth.

 

7. Do op amps work with DC?
In principle, yes, you can amplify DC with an op-amp, subject to the constraints of the amplifier. Mainly, the amplified output voltage must be between the output limits of the op-amp. ... (A fraction of the final output of the power supply is fed back to the op-amp's negative input to regulate the overall circuit.)

 

8. How do you amplify DC current?
A transistor can be used to increase current. You'll have a low current path, from base to emitter in an NPN, and a higher current path from collector to emitter. The collector current will be a multiple of the base current if the circuit allows it.

 

9. What are the ideal characteristics of op amp?
Ideal op amps use no power, have infinite input impedance, unlimited gain-bandwidth and slew rate, no input bias current, and no input offset. They have unlimited voltage compliance.

 

10. What is slew rate of op amp?
Slew rate is defined as the maximum rate of change of an op amp's output voltage and is given units of volts per microsecond. Slew rate is measured by applying a large signal step, such as 1V, to the input of the op amp, and measuring the rate of change from 10% to 90% of the output signal's amplitude.

Ordering & Quality

Photo Mfr. Part # Company Description Package PDF Qty Pricing
(USD)
ADA4895-1ARZ-R7 Company:Analog Devices Inc. Remark:General Purpose Amplifier 1 Circuit Rail-to-Rail 8-SOIC Package:8-SOIC (0.154"", 3.90mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
1000+: $2.62010
Inquiry
MCP607T-I-ST MCP607T-I-ST Company:Microchip Technology Remark:IC OPAMP GP 2 CIRCUIT 8TSSOP Package:8-TSSOP (0.173", 4.40mm Width)
DataSheet
In Stock:7357
Inquiry
Price:
2500+: $0.74000
1+: $0.98000
25+: $0.81000
100+: $0.74000
Inquiry
TLC2652M-8DG4 Company:Texas Instruments Remark:Zero-Drift Amplifier 1 Circuit 8-SOIC Package:8-SOIC (0.154"", 3.90mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
59+: $4.27237
Inquiry
TLE2022MLB TLE2022MLB Company:Texas Instruments Remark:General Purpose Amplifier 2 Circuit TO-99-8 Package:TO-99-8 Metal Can
N/A
In Stock:On Order
Inquiry
Price:
27+: $9.37000
Inquiry
LM324ADTBR2G LM324ADTBR2G Company:ON Semiconductor Remark:General Purpose Amplifier 4 Circuit 14-TSSOP Package:14-TSSOP (0.173"", 4.40mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
1+: $0.44000
10+: $0.38000
25+: $0.35480
100+: $0.26360
250+: $0.22308
500+: $0.21294
1000+: $0.15717
2500+: $0.14703
5000+: $0.13689
Inquiry
UA741MD UA741MD Company:STMicroelectronics Remark:General Purpose Amplifier 1 Circuit 8-SO Package:8-SOIC (0.154"", 3.90mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
Call
Inquiry
TLC2274IPWR TLC2274IPWR Company:Texas Instruments Remark:General Purpose Amplifier 4 Circuit Rail-to-Rail 14-TSSOP Package:14-TSSOP (0.173"", 4.40mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
1+: $1.98000
10+: $1.77800
25+: $1.67760
100+: $1.34200
250+: $1.17424
500+: $1.14070
1000+: $0.90585
2000+: $0.87230
6000+: $0.83875
10000+: $0.82533
50000+: $0.80520
Inquiry
AD627AR-REEL AD627AR-REEL Company:Analog Devices Inc. Remark:Instrumentation Amplifier 1 Circuit Rail-to-Rail 8-SOIC Package:8-SOIC (0.154"", 3.90mm Width)
DataSheet
In Stock:On Order
Inquiry
Price:
Call
Inquiry

Related Articles

Power Amplifier Basic and Classifications Tutorial

Apogeeweb 15 Jun 2019  2711

Making an Audio Power Amplifier   Catalog Ⅰ IntroductionⅡ Operational PrincipleⅢ Primary Classification3.1 Voice Playback System3.2 ClassificationⅣ Basic Structure4.1 Thr...

Continue reading »

Types of Operational Amplifier Circuit Example Overview

Apogeeweb 29 Mar 2021  918

IntroductionThe operational amplifier is an integrated circuit that has two input pins and one output pin. It is used to amplify and output the voltage difference between the two input pins. Based on ...

Continue reading »

Operational Amplifier Principle and Circuit

Apogeeweb 15 Jan 2019  4124

Warm hints: This article contains about 6000 words and reading time is about 22 mins. Introduction The operational amplifier is referred to as an op amp. It was named "Operational Amplifier" because...

Continue reading »

Core Problems about Operational Amplifier Basics

Apogeeweb 22 Nov 2019  3283

IntoductionAn operational amplifier, or op-amp for short is a DC-coupled high-gain electronic voltage amplifier with a differential input and, usually, a single-ended output. In this configuration, an...

Continue reading »

Basic Operational Amplifier Characteristics and Classifications

Apogeeweb 19 Jan 2018  6400

Warm hints: The word in this article is about 3500 and reading time is about 18 minutes. IntroductionIt has been more than 40 years since the analog operational amplifier was born. The earliest proce...

Continue reading »

Current Sense Amplifier Circuit and Application Overview

Apogeeweb 12 Jan 2021  266

IntroductionIn electronics, current sense amplifiers are special-purpose amplifiers that output a voltage proportional to the current flowing in a power rail. They are often referred to as current shu...

Continue reading »

pinglun 3 comments

    • pingluntus
    • Willile on 2019/10/23 16:54:19

    Add something, the op amp can be simply viewed as a high-gain direct-coupled voltage amplifying unit with one signal output port, a non-inverting input, and an inverting put, which belong to high-impedance inputs. So non-inverting amps, inverting amps, and differential amps can be made based on these amplifying units.

    • pingluntus
    • Eills on 2019/10/28 13:45:51

    We should know the principle before calculations, the power supply mode of the op amp is divided into dual power supply and single power supply. For dual-supply op amps, the output can be varied across zero voltage and the output can be set to zero when the differential input voltage is zero. With a single-supply op amp, the output varies over a range of power and ground.

    • pingluntus
    • Comie on 2019/11/11 17:55:57

    The output signal of the operational amplifier is proportional to the difference between the signal voltages of the two inputs. In the audio segment: output voltage = A0 (E1-E2), where A0 is the low-frequency open-loop gain , E1 is the input signal voltage of the non-inverting terminal, and E2 is the input signal voltage of the inverting terminal.

Leave a Reply

Your email address will not be published.

 
 
   
 
code image
Rating: poor fair good very good excellent

# 0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z