Electronic Circuits and Tutorials
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Operational Amplifier (Op Amps) Circuits

1 in/4 out Audio Distribution Amplifier :

2 Wire Remote Microphone Amplifier:

25 Hz Peaking Amplifier :

30Hz to 90Hz Adj P.A. Driver :

4 in/1 out Summing Power Amplifier :

4.5 H. Magnetic P.B. Head Preamplifier :

44 Audio Dist. Ampl. Circuit :

60 to 100KHz Adj. Tape Bias Oscillator :

AC and op amp provide variable control voltage: 12/06/2001 EDN - Design Ideas / Early DACs contained standard R-2R ladder networks, and produced a negative output voltage. These early DACs, such as the MAX7837/7847 and the MAX523, require both positive and negative supply rails to accommodate their negative output. With the transition to single-supply ICs, however, many modern DACs operate with a single supply rail and an inverted R-2R ladder network. .

ACN (Active Combining Network) :

Application Guide for OpAmps: Bitmap Bitmap National Semiconductor Application Notes, 04-Nov-1995  

Applications of the LM392 Comparator OpAmp IC: National Semiconductor Application Notes, 04-Nov-1995

Applying a New Precision OpAmp : National Semiconductor Application Notes,04-Nov-1995

Applying Dual & Quad FET OpAmps : National Semiconductor Application Notes,10-May-1996

Audio Level Meter Amplifier :

Basic OpAmp Circuits:

Bootstrapping allows single rail op amp to provide 0V output: 02/06/03  EDN-Design Ideas / Many single-supply-powered applications require amplifier-output swings within 1 mV—or even sub-millivolts—of ground. Amplifier-output-saturation limitations normally preclude such operation. Figure 1's power-supply bootstrapping scheme achieves the desired characteristics with minimal parts count

100W bridge amplifier based TDA7294

Circuit Provides Inverting / Noninverting Gain: 11/09/95 EDN-Design Ideas

Circuit Provides Linear  Volt to I Conversion: 01/18/96 EDN-Design Ideas

Constant current Amplifier :

Constant current Power Amplifier :

Current Feedback Amplifiers : National Semiconductor Application Notes,05-Aug-1995

DAC & OpAmp Provide Variable Control Voltage: 12/06/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit

DAC and op amp provide variable control voltage:  12/06/01 EDN-Design Ideas /  Early DACs contained standard R-2R ladder networks, and produced a negative output voltage. These early DACs, such as the MAX7837/7847 and the MAX523, require both positive and negative supply rails to accommodate their negative output.

Designing An OpAmp Headphone Amplifier: many circuit examples

Designing With a New Super Fast Dual Norton Amplifier : National Semiconductor Application Notes,04-Nov-1995

Designing With OpAmp: Audio design has for many years relied on a very small number of Op-Amp types. The TL072 and the5532, numbers that will be immediately familiar to anyone involved in audio electronics, have dominated the small-signal scene for many years. There are however other Op-Amps, some of which can be very useful, and a selected range is covered here.

Digital Quality Microphone Pre Ampl. Using the Model 425 OPAMP :

Dual OpAmp Doubles Output Current: 09/12/96 EDN-Design Ideas

Dual Polarity Amplifier has Digital Control: 09/12/96 EDN-Design Ideas

Feedback & Amplification #1: 01/06/94 EDN-Design Ideas

Feedback Network Silences OpAmp Resistor Noise: 09/12/96 EDN-Design Ideas

Feedforward Compensation Speeds OpAmp : National Semiconductor Application Notes,28-Jun-1996

Film Optical Record Amplifier w/ Noise Reduction Circuit :

FM Radio Transmitters With OpAmp :

Frequency Dependant Negative Resistor (Using OpAmps):

High Quality Intercom:

I Feedback Amplifier Puts Parasites to Work: 11/09/95 EDN-Design Ideas

IC OpAmp Beats FETs on Input Current : National Semiconductor Application Notes,04-Nov-1995

IFB Intercom :

Ignore Input Range Limits in Wideband OpAmp: 07/16/98 EDN-Design Ideas

Inductors 6mH to 1600mH :

LH0024 & LH0032 High Speed OpAmp Applications : National Semiconductor Application Notes,04-Nov-1995

Linear power driver works from single supply: 07/25/2002  EDN - Design Ideas / (added 10/03)    In low-power, single-supply analog applications, it is often desirable to maintain precise control of voltages much greater than the positive-supply rail. The circuit in Figure 1 allows you to amplify the input voltage, VIN, by a factor, A, which resistors R1 and R2 set. The output voltage, VOUT, equals AVIN, where A=R2/(R1+R2).

LM118 OpAmp Slews 70 Volt / Microsecond : National Semiconductor Application Notes,28-Jun-1996

LM3900New Current Differencing Quad of Plus or Minus Input Amplifiers: National Semiconductor Application Notes,04-Nov-1995

LM6361 / LM6364 / LM6365 Fast OpAmps: National Semiconductor Application Notes,04-Nov-1995 / Offer High Speed at Low Power Consumption

Low Distortion Wideband Power OpAmp : National Semiconductor Application Notes,04-Nov-1995

Low Noise Precision OpAmp : National Semiconductor Application Notes,28-Jun-1996

Low Power Op Amp   Audio Amp (Intercom):

Main Principles of Amplifier Wiring : How to wire operational amplifier 

MicroPower using the LM4250 Programmable OpAmp : National Semiconductor Application Notes,04-Nov-1995

Monolithic OpAmp the Universal Linear Component : National Semiconductor Application Notes,04-Nov-1995

Monolithic Power OpAmp : National Semiconductor Application Notes,01-May-1998

Multi track Recording System :

Negative Resistor Cancels opamp Load: 05/24/01 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

New OpAmp Ideas : National Semiconductor Application Notes,04-Nov-1995

Noninverting op amp circuit has simple gain formula: 11/28/2002  EDN - Design Ideas / Basic textbooks describe inverting and noninverting amplifiers based on operational amplifiers. These amplifiers have different gain equations. Whereas in the inverting configuration, the gain is the ratio of the feedback and input resistances, in the noninverting amplifier, the gain ratio has an added term.

Op Amp improves Power Supply's Regulation: 06/05/96 EDN-Design Ideas

Op amp linearizes attenuator control response: 07/25/2002  EDN - Design Ideas /  Professional-audio equipment commonly uses Analog Devices' (www.analog.com) high-performance, quad-voltage-controlled SSM2164 attenuator. The control response is -30 dB/V, with 0V producing unity gain. Attenuation increases as the applied control voltage increases in the positive direction. The circuit in Figure 1 extends the range of applications for this versatile chip by providing a simple.

OpAmp Basics:

OpAmp Booster Designs : National Semiconductor Application Notes,09-Apr-1996

OpAmp Circuit Collection : National Semiconductor Application Notes,04-Nov-1995

OpAmp Design & Test Board:

OpAmp Doubles As Instrumentation Amp: 09/15/94 EDN-Design Ideas

OpAmp Linearizes Response of FET VCA: 09/05/02 EDN-Design Ideas / Fets find common use in VCAs (voltage-controlled amplifiers) and attenuators, in which the FET serves as a variable resistance. A control voltage applied to the gate sets the channel resistance and overall circuit gain.

OpAmp Makes Precise 9 Volt Battery Splitter: 07/17/97 EDN-Design Ideas / Alkaline 9V batteries are ideal for many portable, handheld applications, this circuit generates a bipolar supply of5V and ­2.3 to ­4V using a precision5V reference and one op amp as a supply splitter

OpAmp Oscillators Simplify RF Designs: 10/10/96 EDN-Design Ideas

OpAmp Radio:

OpAmp Rectifier Signals Input State: 07/21/94 EDN-Design Ideas

Optical Magnetic Projection Booth System:

Party line Intercom :

Phonograph Disc Playback Preamplifier :

Phonograph Disc Record Amplifier :

Piecewise Linear Amplifier Eschews Diodes: 10/12/95 EDN-Design Ideas 

Portable Mixer for Nagra Recorder :

PWM Circuit uses one OpAmp: 07/06/00 EDN-Design Ideas / circuit delivers a rectangular signal with duty cycle varying between0 and100% in response to an input signal varying from0 to5V dc

Railtorail op Amp Provides Biasing in RF Amp: 01/20/00 EDN-Design Ideas / PDF contains multiple circuits - scroll to find this circuit.

RF oscillator uses current feedback op amp: 10/03/2002  EDN - Design Ideas /  A current-feedback amplifier is a well-known component with many uses. Its basic block diagram shows that its input stage is a voltage follower—in practice, a symmetrical emitter follower (Figure 1). The configuration samples the output current, converts it to voltage across a large impedance, and amplifies it to the output using a high-power, low-output-impedance amplifier..

Simple Op Amp Radio:

Simple Timer Exploits OpAmp Bias Current: 07/21/94 EDN-Design Ideas  

Single NiCd Cell Drives OpAmp: 12/05/96 EDN-Design Ideas

Single Polarity Powe Supply Circuit for 400 series Amplifiers :

Slow OpAmp Makes Fast Multivibrator: 01/01/98 EDN-Design Ideas

SwOpAmp Makes Square Wave Generator: 02/15/96 EDN-Design Ideas

TO 3 Case Low Power Amplifier :

Topics on using the LM6181New Current Feedback Amplifier : National Semiconductor Application Notes,05-Aug-1995

Transformerless Microphone Preamplifier :

Tutorial on Applying OpAmps to RF Applications : National Semiconductor Application Notes,02-Apr-1999

Two OpAmps Make Fast Full Wave Rectifier: 03/14/96 EDN-Design Ideas

Two wire Remote Microphone Amplifier :

Use the LM158 / LM258 / LM358 Dual, Single Supply OpAmp : National Semiconductor Application Notes,04-Nov-1995

V 44 Video Distribution Amplifier Schematic :

Versatile ShiftKeying Generator Uses CurrentFeedback Amplifiers : 06/24/02 Electronic Design - Ideas for Design / Digital information often must travel through analog channels in applications like satellite communication, digital cellular phones, digital microwave communication, and others.

Video multiplexer uses high speed op amps : 08/21/03  EDN-Design Ideas / Video multiplexers route video from several sources to a single channel. Low-end consumer products use CMOS analog switches and multiplexers, such as the 4066 and 4051. Unfortunately, these devices have a series on-resistance that ranges from approximately 100O to 1 kO.

Wideband OpAmp Capable of MicroPower Operation : National Semiconductor Application Notes, 24-Oct-2001

Working With High Impedance OpAmps : National Semiconductor Application Notes,04-Nov-1995

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