Questions tagged [operational-amplifier]
Questions relating to the construction and applications of operational amplifiers, which are DC-coupled, high-gain electronic voltage amplifiers with a differential input and, usually, a single-ended output.
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Delay-Free Switched-Capacitor Integrator Difference Equation Derivation
I want to derive the difference equation of a delay-free SC integrator using charge-domain analysis.
Here's the example I am following. This shows you that for charge domain derivation, all you need ...
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Feedback mechanism intuition
There is a circuit taken from the presentation below.
Suppose at some point the VFM voltage rises from V0 to V0 + 0.01 V so V_minus of the op-amp rises too. So what causes the voltage on VFM to return ...
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Why doesn't my current source simulation in LTspice work?
I am trying to simulate a voltage-controlled current source in LTspice using the feedback current of an OP-amp as the load current. My circuit is:
As an output, I get something around I_L = 620pA. As ...
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op07c null offset with a digital potentiometer
I am using an op07c in a circuit and can null the offset very well using a 20k pot. I want to replace this pot with a digital pot. I now have a 5k resistance, a 10k digital pot and another 5k ...
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LTC 2065 is not working between 2 V - 4 V power supply
I'm having a problem with the LTC2065 operational amplifier design. I use a 3.3V supply as I show in the picture, and after boosting my input signal I make it oscillate at 1.8V using a 1.8V virtual ...
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Optimizing Solenoid Control Circuit with FETs: Minimizing Inrush Current and Hold Current Precision
I'm creating a circuit using two FETs. The first FET (U2A) is responsible for controlling the inrush current of the solenoid, and the second one (U2B) is used to maintain the predetermined hold ...
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Development of a calibration procedure and calibration of the instrument [closed]
I am working on a Measurement and Noise lab project which includes LF353 op-amp, MPX2012DP pressure sensor, breadboard, sensor signal amplifier board, readout multimeter, power supply unit, and ...
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Calculate the output I° for the following network [closed]
strong text
Kindly solve this for me tomorrow is my exam
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OP07 unity-gain stability
Is the OP07 unity-gain stable? I am powering it with a +/- 5V supply. I am using it to buffer a DC signal which varies slowly.
Most of the modern op-amps have their datasheets mentioning them ...
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Practical Opamp Buffer Output Offset and Clipping Behavior
I'm designing a full-wave precision rectifier using OP07 in LTSpice. The first stage of the circuit (shown below) buffers the AC input using an OP07.
But the buffer output is clipped with a ...
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Why is the feedback of op-amp oscillators connected to inverting input instead of positive input
I'm new to the subject of oscillators and learned that sustained sinusoidal oscillations are made possible by positive or regenerative feedback. Is that right? If that's true then I can't quite grasp ...
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Single op-amp with "isolated" positive input pin or method to invert the feedback loop?
To improve isolation between the input and the other pins of a circuit, I used an MCP6001R SOT-23-5 op-amp which has a pin-out like this:
I am interested by the fact that there is quite some space ...
CommunityBot
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What is the definition of "the loading of feedback network on the input/output side"?
There is the following example:
simulate this circuit – Schematic created using CircuitLab
Its loading of the feedback network on the input side is 40kohm in series. Its loading of feedback ...
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Why isn’t my overdrive circuit working?
I have attached an image of an overdrive circuit that I have designed for a guitar pedal. I have built the circuit and it isn’t working and I wanted to find out if there were any obvious design flaws/...
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How I can use light to control of amplifier?
I want to make a car that I can control by light, and I thought of using a photoresistor and a light sensor to control the amplifier to make it perform two functions.
The first function is to make the ...
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Voltage gain of this OPA circuit with AC input
The aim is to attenuate 10 times and cutoff frequency of at least 10 MHz.
I understood that the green section of the circuit reduces the voltage gain. I have noticed that increasing the orange section'...
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Making block diagram of an op-amp configuration
Hi everyone,
I have to make the block diagram of the above configuration. Supposing the input capacitance of op-amp Cin, I've drawn this:
A is the open loop transfer function of the OPA.
B is the ...
CommunityBot
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Why am I getting this distortion in this circuit?
Can someone explain to me why I am getting this distortion for the following circuit? Input is a pure square wave. It happens at any input frequency or voltage. I was thinking the output would be a ...
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OpAmp Selection | Sine Wave Amplifier: 30 MHz, 30Vpp with 15V offset
I am currently working on amplifying the output sine wave of the TG5011 professional signal generator. Below are the specifications for the amplifier I am aiming to create:
Power Supply: A single ...
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Why does my 741-op-amp integrator have different cut-off and 0 dB frequencies for different waves if it is a true first order active low pass filter?
I made this integrator circuit by following this diagram. Now, according to the wikipedia, an integrator circuit is an active low pass filter which you can see in the picture below:
So, the cutoff ...
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Generation of a high-resolution triangle wave [closed]
I am trying to generate a triangular wave of frequency ~ 100 kHz and V(p-p) = 4.5 V.
Additionally, I also have a tight specification that the value of the peak of triangular wave generated in each ...
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No Output for Preamp circuit in TINA
Is this a spice problem or a design(me) problem? The rails are producing the expected 9 and -9 volts, but nothing is coming through on the output. I haven't ever done op amps without a bias voltage ...
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AC to DC converter from ICL7106 datasheet [closed]
Can somebody explain me how does this circuit work? I have seen this in datasheet of ICL7106.
Image Source: Renesas (Intersil) ICL7106 datasheet
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How do I Rename a .301 file to add a component to Tina-ti?
I'm trying to import a model of an NE5534 to TINA-ti that I downloaded from the TI site. The file has the .301 extension. I'm not really sure how I can use this, because I need a .CIR, .LIB, .MOD, or ....
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fixing real life offset of a simulated amplifer question
My simlation shown below has no offset voltage problem at all.
However in real life I am afraid that I would get a constant offset to the output instead of zero .
Am I correct?
I tried to plus many ...
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MCP6548 comparator circuit isn't working
Hey guys back at it again, sorry.
I am using a standard MCP6548 Comparator to finish the first stage of my project.
simulate this circuit – Schematic created using CircuitLab
OP's schematic.
...
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Need help with an IR demodulation circuit
I'm trying to reverse engineer a PCB and made a schematic.
The bad thing is I only have PCB images from both sides, not the actual PCB. This PCB is used to detect a very small black object spinning at ...
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Suggestions for Improving this Pre-amp Circuit
I made this preamp circuit for a dynamic mic and am mostly happy with it, but I'd love to get suggestions on how to make it a little better. I'd like it to have as little coloration as possible, and ...
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Isolation of Input signal and supply [closed]
I have this op-amp like circuit. Where the input signal is an 70V High voltage signal and the power supply is 3.3V voltage signal to a MCU GPIO.
My question is how should I isolate the high voltage ...
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Contradictory closed-loop behaviour of TL051CP op-amp
I tried to set up the TL051CP op amp as a current-voltage converter, but in a configuration somewhat different from the usual current-voltage converter setup with the non-inverting input simply ...
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Series voltage regulator op-amp
I am using LTspice trying to find out the extremums of tbmhe output of the following circuit. The diode, op-amp, and PNP transistor are the default components.
What I know at the moment is that \$V_{...
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LTSpice modelling for a DC load
I am new to LTSpice and am working on modelling a DC Load circuit using NMOS and an opamp. I wanted my simulation to be as accurate as possible so I downloaded the spice model for LM358 OPamp and ...
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How do I find Vo in the circuit?
I1 + I2 = I3
I1 = Vi/Z1 ... Z1 = (1+sCR1)/sC
I1= Vi(sC)/(1+sCR1)
I2= Vi/R1
I3= -Vo/R1
I1 + I2 = I3
Vi[(sc)/(1+sCR1) + (1/R1)] =-Vo/R1
-Vi[(R1sC)/(1+sCR1) + 1] = Vo
How do I change back to time domain?
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what nV/rtHz means in the context of signal resolution?
From what I have done so far, V/rtHz is a form of expression for the amount of noise in a bandwidth.
How ever, I came across this paper where they mention the minimum resolution of a signal (in table ...
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Why Am I Not Getting my Expected Output in this basic Op-Amp Circuit?
I thought that A = 1 + Rf/Ri for an op-amp non-inverting amplifier? With a 1mV input, I'm getting output voltages in the uVs...
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AD711 Noise Figures
I'm looking at the datasheet for the AD711. Why are there several different values for the input voltage noise given without any information to distinguish between them?
Datasheet: AD711
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Multisim, Simulation Error
As the picture describes, the Vout is the division's result, but we have an error. Because my experience with MultiSim is not at a high level, why does this happen? Is this my fault ?
]1
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Photodiode op amp circuit, incorrect or correct output?
I am using the S12053-02 APD and the ADA4817 op amp. I'm not really sure if I'm getting the correct output or if the configuration I have is the best. I am trying to get a near 1 to 10 nA to mV, so if ...
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Understanding the working of the diode in opamps [closed]
I had seen one of the schematics where I found a diode in the feedback loop. The schematic is shown below, where I have two inputs from 0-5. I have the following questions about this:
What is the ...
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Designing a differential equation circuit with op-amps
I have the following assignment question
The differential terms all contain the output voltage in differential forms. My first thought was to then implement op-amp as integrators in each stage since ...
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Smallest current-controlled voltage source in an IC?
You can multiply a vector and a matrix by encoding the vector in voltages and the matrix values as conductances of variable resistors (using eg floating gate transistors or phase change memory). The ...
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What's special about "unity-gain stable"?
As mentioned in opamp datasheets, like this one. I would think stability is a problem at higher gains, due to oscillation. What are the problems with unity-gain?
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Brushed DC Motor - Driving Forwards With PWM AND Detecting Reverse Motion
I would like to drive a small 9V brushed DC motor using PWM from a micro-controller and came up with the standard circuit of: micro-controller PWM out (J1) connected to a mosfet gate with a current ...
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DC voltage amplifier circuit with up to 10kV output, up to 1mA
What components would I need for a circuit that would be able to magnify an input voltage in the 10s of volts at an appropriate wattage to produce an output voltage of up to 10kV at 1mA? I've read ...
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Op-amp circuit stability (LTspice)
I want to study the stability of my op-amp circuit with LTspice. I found this video as tutorial: tutorial on phase margin
I did the simulation with closed and open loop as suggested and got the ...
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Low side BLDC motor phase current measurement
I'm trying to design a current sense circuit for measuring a phase current in a BLDC motor. Here I'm using the embedded opamp in the STM32G4 MCU. What voltage will be at the output of the opamp here ? ...
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How to find a Pin-to-Pin Replacement for TL-081, but with higher VCC? [closed]
After ordering and assembling one of those¹ "red" 0-30V/0-3A power supplies from eBay/AliExpress and taking a bit of a closer look at it, I'd like to replace the TL081CP op-amps. It's ...
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Asymmetric Op-Amp Output - Transconductance Amplifier
I'll preface this post by saying I am a power engineer working in the utility world and my electronics knowledge is very rusty. The last time I worked with electronics was back in undergrad (~6 years ...
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Non inverting op amp issue
I'm using an lm3900 quad op amp to run a smart phone audio signal to a bs170 MOSFET. When I use the inverting configuration it works well, but when I use the same resistor values (1k and 10k) with the ...
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Amplifier circuit design for ADC: Could input voltage mix with reference voltage?
This might be a silly question. I saw this from "Opamp For Everyone" and was a bit confused with this circuit. The book doesn't mention the signal source at all, I think it does have a ...
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