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Operational amplifiers have a very broad range of application.   This book focuses on the fundamentals which are applicable to many applications.  All of the simulations and experiments demonstrate basic operational amplifier principles.   The experiments may be easily modified and may serve as the basis for other applications. 

 This book may be used as a circuit design and application reference for hobbyists, experimenters, and students.  It may also be used as a supplement to a college level operational amplifier course and laboratory.  An understanding of electric circuit analysis, semiconductor devices, and college level algebra are pre-requisites for this book. 


Simulation examples are presented using LTspice, a simulation program available as a free download from Linear Technology.   TINA-TI, a simulation program available as a free download from Texas Instruments, is also introduced.


Experiments provided may be performed using a solder-less breadboard, inexpensive parts, a small power supply, and a digital or USB oscilloscope.  Some experiments also require a function generator.  The circuits are provided in their basic and simplest forms.  The experimenter may modify and augment the circuits as needed for particular applications. 

Op-Amps Circuits: Simulations and Experiments

Chapter 1: Op-Amp Characteristics

Operational Amplifier: Open-Loop DC Model

Non-Inverting Amplifier

Non-Inverting Amplifier Closed Loop Voltage Gain

Non-Inverting Op-Amp Input Impedance

Op-Amp Output Impedance

Inverting Amplifier

Differential Amplifier

Instrumentation Amplifier

Op-Amp Input Offset Voltage and Input Bias Currents

Inverting and Non-Inverting Amplifier Offset Current Error

Inverting and Non-Inverting Amplifier Offset Voltage Error

Offset Compensation

Frequency Response

Phase Margin

Slew Rate


Amplifier Noise Model

Differential Amplifier Noise Model

Signal-to-Noise Ratio

Noise Factor

Noise Figure

Chapter 2:  Op-Amp Circuit Simulation

Simulation: Buffer Amplifier

Simulation: Non-Inverting Amplifier

Simulation: Inverting Amplifier

Simulation: Offset Voltage and Offset Current

Simulation: Op-Amp Noise

Simulation: Frequency Response and Noise

Simulation: Transient Response

Chapter 3:  Filters

Low-Pass Filters

Second Order Low-Pass Filter

Second Order Low-Pass Butterworth Filter

High-Pass Filters

Second Order High-Pass Filter

Second Order High-Pass Butterworth Filter

Band-Pass Filter

Infinite-Gain Multiple-Feedback Band-Pass Filter

Notch Filter

Twin-T Notch Filter

Chapter 4:  Oscillators

Relaxation Oscillator

Triangle wave oscillator

Phase Shift Oscillator

3-Phase Oscillator

Wien Bridge Oscillator

Chapter 5:  Projects

Project 1:  Variable Voltage Power supply

Project 2: Regulated Power Supply

Project 3: Light Meter and Switch

Project 4: Phase Tripler

Chapter 6: Magnetic Applications

Project 5: Hall Effect Magnetometer

Project 6: Geophone Amplifier

Project 7:  Sensor Amplifier and Geophone damping


Chapter 7: Low Frequency Receivers

Project 8: ELF Receiver Design

Project 9: Broadband VLF Receiver Design

Project 10: Tunable VLF Receiver

Project 11:  Gyrator Tuned VLF Receiver

Chapter 8: Photo-Resistor-Coupler Applications

Project 12: Photo-Resistor Opto-Coupler Simulation

Project 13: Voltage Divider

Project 14: Voltage Controlled Oscillator

Project 15: Audio AGC and Compressor Circuits

Project 16:  Tremolo Circuits


Op-Amp Data Table

SS495 Hall Sensor

LM385-1.2 Voltage Reference

TIP120 NPN Power Transistor

RTC – 4.5-395 – Vertical Geophone

NJL7502L Photo-Transistor

Resistor Color Code

SD103A Schottky Diode

1N4148 Signal/Switching Diode

1N400X Rectifier Diodes

NSL-32 Photo-Resistor Opto-Coupler


ZX1 Photo-Resistor Opto-Coupler LTspice Model

ZX1A Photo-Resistor Opto-Coupler LTspice Model

ZX4 Photo-Resistor Opto-Coupler TINA-TI Model


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