An op-amp (operational amplifier) is a high gain analog voltage amplifier with differential high impedance inputs, and a low impedance output. A basic building block in signal processing, like as amplifier or active filter.

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Transfer Function of PI Controller

Circuit below is an op-amp summer combined with PI controller. simulate this circuit – Schematic created using CircuitLab What is transfer function of this circut? How to calculate each ...
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47 views

Calculate Vout from an op amp

I have a op amplifier for which I want to calculate Vout depending on Vin. The circuit looks like this: I know that with a circuit that just has ground connected to + of the amp, i can just ...
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120 views

Questions on Operational Amplifiers

What I've learned so far from Navy school is that operational amplifiers are used as a substitute for transistor amplifiers and they contain three main circuits: the differential amplifier, common ...
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What type of op amp should I use in this thermistor signal conditioner?

I'm designing a thermistor signal conditioner for existing probes. I'm not linearizing in hardware, there is plenty of time to do it in firmware. The thermistor has a resistance of \$\text 7.5\text ...
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40 views

Can this gyrator handle high current and/or high voltage?

Since I first got introduce to the Antoniou Inductor while in university, I've always been amazed at it. I've never built or used one, but I am thinking about using it to simulate an inductor for a ...
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25 views

Protecting opamps from back-EMF, necessary or common in 70/100V audio?

Clayton and Winder's opamp book 5th ed. p. 283 briefly discusses the use of Zener diodes to clamp (as a TVS) voltage spikes from inductive loads from taking the opamp's output stage above its power ...
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59 views

Basic Filter Design

Need help with basic filter design. Firstly there is a low-pass filter(pictured below). I am supposed to derive an expression for the amplitude of the output voltage as a function of \$R_1\$, ...
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54 views

Op-Amp difference amplifier low-pass filter

I have the following (summing, single supply) difference amplifier circuit: How can I extend this circuit to a 1st or 2nd order low pass filter, with a corner frequency at about 20kHz.
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Why is a 0V DC point at the output of an op amp critical for feedback?

I am designing an op amp that consists of an active loaded single ended output differential amplifier that is connected to a buffer stage and then an output stage. When the input signal is connected ...
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Understanding Block Diagram for Load Switch

I'm looking at the Vishay SiP32431 and am confused by the block diagram, copied below. I understand the P-Channel at the top, but what are the triangles? What is the difference in level-shifting ...
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35 views

Help with Op-Amp project

I have an Op-Amp project, and im stuck on the last part of it; I was wondering if anyone would be able to help; http://imgur.com/GdEWKMN (project outline) http://imgur.com/FVPEr4C (Part A solution) ...
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46 views

Simple output stage for a voltage output audio DAC

I am trying to design a simple output stage for a voltage-out audio DAC. The DAC has an differential output. In the following image VOUTP is the non-inverted output and VOUTN is the inverted output, ...
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42 views

Opamp filter cutoff frequency not as expected at higher frequencies

I'm still working on learning Butterworth filters. So far this weekend I went back to school, read about Lapace transforms, poles and zeros, Saleen key design, and finally back to Butterworth filters ...
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58 views

Changed Op-amp, now signal is not centered

I'm making a pre-amplifier for my 9mm electret microphone to be read by an Arduino. Here's the schematic: Note that the resistor I used connected to the output is 1Meg. My supply voltage is 5V. ...
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2answers
54 views

What is the best practice to generate positive and negative voltages to power an OpAmp [duplicate]

I would like to supply +4.5V & -4.5V to OpAmp using a 9V battery. I have tried using voltage divider which works. Please suggest if this is the best practice, are there any better ways of doing ...
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45 views

Transducing a changing capacitance

I have a capacitor C which changes with time. Now I want to measure the varying capacitance as a voltage function, so I need to design a circuit for that. My motivation around the problem is that, I ...
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56 views

Op-Amp working principle

In the op-amp working principle I was told that if I have a certain input voltage at the non inverting pin, then the inverting pin will also be forced to have that voltage and hence if I attach a ...
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35 views

eliminitaing spikes from the circuit input

Suppose I have a circuit which gets damaged for spikes and high voltages, so that I need to eliminate spikes and high voltages beyond a maximum value, so I have decided for the following two ...
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62 views

Calculating Op-amp supply bypass caps values

Either I suck at searching or there is not a lot information about calculating values of bypass caps for opamps(I found a bunch on the topic in general). The question is, what it says in the title, ...
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48 views

Is the cut-off frequency for each high order butterworth filter the same or different?

From reading I see that I can calculate my cut-off frequency for a given Butterworth filter using the equations below. Let's say then that I have a 8th order filter, and I'm going to make it out of ...
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68 views

High Order Butterworth Filter Math

I'm trying to learn more about high order filter design, with my goal being to design an 8th order Butterworth lowpass filter in spice, then in the real world. I've been reading a filter book I have ...
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42 views

calculating the input current that can be taken by an Operational amplifier

Is there a way to calculate the input current that can be taken by an Operational amplifier, if we know its input Bias and input offset current?
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121 views

Determine input resistance of a DMM using a voltage follower

In my electronics lab we constructed a voltage divider that consisted of two \$1\$M\$\Omega\$ resistors and measured the voltage drop between the two resistors and ground. We supplied \$15\$V and ...
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48 views

Using a LM1875 instead of a LM675 for virtual ground

I've been gawking at the data sheets of these two, and I don't see any great disadvantage in substituting the TI recommended part (LM675) for the audio part LM1875 in this application (virtual ground, ...
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57 views

How to eliminate 50 Hz noise from amplifier's output

My goal is to amplify signals with a frequency from 100Hz above. My circuit is looking as the picture below. With an oscilloscope, I am trying to measure the output of the amplifier. If the input of ...
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52 views

Using Op-Amp for attenuation to give input to sound card

I know there is lot of question asked about this topic before, I read them but there are some limitation on those circuits which make me ask this one. I want to do analysis of main ...
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130 views

Identifying a component symbol in a schematic [duplicate]

Problem: So I have ran across the following part and I simply don't know what it is. I tried searching for if you will a description of it. (I.E. two diodes on top of each other pointing opposite ...
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51 views

What is the correct transfer function of a feedback loop if the summing amplifier has different input resistors?

Suppose I have a circuit below: simulate this circuit – Schematic created using CircuitLab I know the the transfer function of a negative feedback loop is: ...
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39 views

Dual Supply Voltages in Op-Amp Circuit & Op-Amp parameters

I have few questions about Op-Amp circuits that i could not found the right answer with my research. These are; Why do we need dual supply voltages in Op-Amp circuits ? Which parameter of Op-amp ...
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30 views

Understanding High Side Current Sense OpAmp Datasheet

I'm considering the INA199A3, AD8293G80 or TS1102-100 (decreasing cost order) for a high-side current sensing application. According to my understanding the output voltage error is mainly affected by ...
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48 views

temperature compensation circuit using AD8515

Can I use AD8515 op-amp as temperature compensation circuit for pressure sensor? The picture shows how I intend to use it.
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80 views

Calculated output is greater than the op amp can produce?

I had to analyze a differentiator and integrator op amp. I am now asked the question of what would happen if the calculated output is greater than the op amp can produce? I am given a hint that it is ...
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54 views

How can I implement a proportional error control scheme with op amps?

So I have an IR distance sensor that I would like to use to keep two wheels (with DC motors) travelling parallel to the wall beside them. I have these proportional error control formulae to keep the ...
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Keeping two wheeled wall following robot straight [migrated]

I have a two-wheeled (two DC motors) robot that needs to follow the wall beside the robot. The issue is that the DC motors spin at different rates (because they are not identical, of course), so the ...
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106 views

Is it good to have a higher slew rate ? What are some of the effects due to slew rate limitations?

This question is in relation to the working of an op-amp. I know what slew rate is but I am not entirely sure whether is it good to have a high slew rate. As far as my understanding goes, a higher ...
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74 views

Transfer function of amplifier

Hello everyone, I would like to find transfer function between input signal \$U_1\$ and output signal \$U_2\$. So, I know how to find the transfer function of each op-amp, for example, 1 transfer ...
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81 views

All sorts of fail converting Schematic to Bread Board

Schematic: Fritzing BB View: Total n00b: I am trying to layout my breadboard based this schematic, but I'm not sure if I've even come close. The LM34 in the graphic is actually a SS494B hall ...
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64 views

what's the difference between these two low pass filter types

Is there any difference between these two types of lowpass filters? I see the equation is the same, I assume they're both first order then. Just curious if there's any practical difference. Maybe ...
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142 views

LM324n weird output when used as buffer

I am using an LM324n quad-core op-amp. I have connected it between +24 V and GND. One of its op amps is used as a buffer. When I pass the buffer a negative voltage, I get it inverted at the output ...
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274 views

Op amp has a biased output

I'm designing an op amp circuit to amplify 20mV, 18kHz square wave up to measurable levels (~2-3V). Why is the output signal: Biased at ~400mV Triangular (high output capacitance? is that a thing?) ...
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110 views

Need help with OpAmp and FET choice for a VCVS

I want to build a voltage controlled voltage source that will supply power to a resistive load (\$1.67\,\Omega\$, \$\approx\$ \$7\,\mathrm{A}\$ @ \$12\,\mathrm{V}\$). The load's dissipation will be ...
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64 views

Advice to improve my microphone circuit

I'm still working on a circuit to hear my heartbeat. I've come a long way but it still doesn't sound as good as some example recordings I've heard. I was wondering if someone could spot something ...
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35 views

op amp differentiator with internal resistance of source generator

I have to analyze an op amp differentiator. I know how to do this with an ideal source generator, but the one I have to analyze has 600 Ohms of internal resistance. I can't figure out how I would go ...
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97 views

Calculate value of output voltage?

I tried to solve the question but my answer seems to be different from that in the text( according to which answer is -30 V). please help me solve it. This is what I did V+ = V- = -2 V (-2 - ...
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65 views

Low voltage adjustable DC power supply (0.1 to 0.75V DC) @ 300 mA

I need to create an adjustable DC power supply that can output between 0.1 and 0.75V DC at 300 mA (possibly as little as 100 mA). My input voltage can be anything, including +/- rail. Currently I am ...
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63 views

Guitar Pre-Amp stage/filtering and STM32F4

I am currently involved in an academic project which the topic is to design a Digital Tuner for Electric Guitars. My knowledge of electronic is very basic, so here I am. I need to pre-process the ...
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106 views

Generating a ±70 V supply for op-amp

I am using the LTC6090 op-amp (links to datasheet) to generate a high voltage, low current voltage. However I've never really done anything regarding DC voltages this high before, so I was wondering ...
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106 views

Need help with a R-2R DAC Circuit

I am trying to simulate a 4-bit DAC circuit using a R-2R resistor ladder. I am using a 741 op-amp. I selected the R value as 10k and calculated the value of Rf using the equation given on this page - ...
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Dual supply op amp LDO does not work but single supply does

I'm designing a LDO with dual outputs (Vout and -Vout), only positive output is shown in the pictures bellow. I'm having large trouble using dual supply op-amps in the design, my single supply one ...
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3answers
110 views

Non ideal op-amp equivalent circuit output voltage

I am creating this question to ask you about a "strange" behavior I am observing in Matlab about an op-amp circuit. I am reading "Fundamentals of Electric Circuits" the 5th edition, and in the chapter ...