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Questions tagged [inverting-amplifier]

Anything related to inverting amplifiers, i.e. amplifier circuits whose output is an amplified replica of the input but which exhibit a 180° additional phase shift.

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General Formula for the inputs to an op-amp?

I was wondering if there is a single formula that expresses the voltage to the inputs of an op-amp, lets say an inverting op-amp, in every case? In the example attached, I understand how the ...
5eamus's user avatar
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2 answers
91 views

Should I use an op-amp buffer so I'm not affecting the original source's current requirements?

I'm attempting to modify an existing product (a dance stage similar to Dance Dance Revolution) where the panel signal is held high (5V) and when it is pressed it pulls the signal low (0V.) Only High (...
SenPi's user avatar
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3 answers
176 views

"Inverting op-amp" circuit calculations using the general feedback formula

I managed to derive the "non-inverting op-amp" circuit using equations from the general formula of negative feedback. Unfortunately, I could not calculate the "inverting op-amp" ...
slimcolt's user avatar
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3 votes
4 answers
204 views

How can I find Thévenin equivalent circuit of the NFB op-amp input? [closed]

I need to find the Thévenin equivalent of the right side of the circuit by looking into node E and F. How can I find it?
LSK's user avatar
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3 votes
3 answers
318 views

Need help inverting DC voltage without op-amp

I am implementing digital voltage and current measurement on an old power supply. Due to the design of the supply, I am forced to use the positive output probe as a common ground for my ADC and MCU. ...
Atropin's user avatar
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2 votes
2 answers
209 views

T-network feedback of opamp [closed]

How are the output (Vo) and H(s) = Vo/Vin calculated in this schematic?
NHẬT BÙI ĐOÀN MINH's user avatar
1 vote
2 answers
45 views

Inverting amplifier with and without headphones load

I made a circuit as the following design: R_fb is 2.25k in our case I am expecting that there wouldn't be negative part of the output waveform. As expected, without the headphone load the measurement ...
Gamer Leaner's user avatar
2 votes
3 answers
186 views

Why is step response of an opamp linear/exponential?

My step response for LM741 at LTSpice was this: And for TL081: So as you can see the response of LM741 is linear and of TL081 is exponential, but why? My schematic is an inverting amplifier with v=...
M S's user avatar
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3 answers
123 views

Inverting opamp amplifier: frequency response not compatible with LTspice simulation

I have a simple inverting opamp amplifier and I want to study the frequency response of the circuit and finally calculate the frequency band (or cutoff frequency). Unfortunately the model created in ...
Gabriele's user avatar
3 votes
3 answers
515 views

Voltage Buffer Vs Impedance matching

I am designing an Amplifier circuit for the microphone. For this, I am using a buffer in between two stages for isolation and I am confused between 2 circuits. I know, in voltage buffer circuits, the ...
ishankhowal's user avatar
1 vote
1 answer
180 views

Why is the opamp's inverting input not at virtual ground?

I've have been trying to make a current to voltage converter using a transimpedance amplifier circuit. I have been simulating the circuit in LTspice and everything seems fine, but when I built the ...
Rasmus Madsen's user avatar
11 votes
4 answers
3k views

What is the purpose of including (or excluding) the output resistor in the feedback loop of an op-amp buffer?

I have often seen (and made) circuits like this. It is a simple inverting op-amp buffer, plus a small current-limiting output resistor to protect the the op-amp if the output is shorted. simulate ...
QuinnF's user avatar
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1 answer
238 views

How can I calculate the gain of this high pass active filter?

This is the circuit I'm trying to make: This is the circuit I made for simulation in Proteus: These are my measured values as a result of Proteus simulation. This circuit is used to measure the ...
bevren15's user avatar
2 votes
1 answer
178 views

Components Used in an Opamp Circuit Measuring AC Voltage

Why do we use this capacitor in the opamp and why do we superimpose it on the DC voltage and then destroy it again with the capacitor? I got some answers here, but as @SamGibson pointed out, I opened ...
bevren15's user avatar
1 vote
4 answers
437 views

Why do we use this capacitor in the opamp and why do we superimpose it on the DC voltage and then destroy it again with the capacitor?

I am interested in the ZMPT101B circuit and there are a few things I cannot understand. This circuit is designed to measure AC Main voltages between 50Hz and 80-250V and to be read from an MCU like ...
bevren15's user avatar
2 votes
4 answers
335 views

Conception of an inverting op-amp with a specific gain

Consider the following circuit: Consider the input voltage is \$v_1 = 0.1 \sin(\omega t) \$ with maximal current \$ 5 \mu A \$. I am asked to manipulate the circuit such that the gain is of \$ A_v = -...
HellBoy's user avatar
2 votes
0 answers
123 views

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 ...
Vitaliy Petliakivskyi's user avatar
4 votes
3 answers
245 views

Fullwave rectifier with active clamp

What is wrong with my simulation? I am simulating with LTspice the following circuit taken from "Art of Electronics 3ed" where my LTspice model looks as follows: What am I doing wrong as ...
abg1984's user avatar
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1 answer
262 views

In testing this op-amp, I always get same amplification. Did I break it?

I bought these TL072 (maybe TL072CD) IC amps, for a circuit I was trying to build, but the circuit wasn't working at all so I tried to troubleshoot the amp. I built a voltage divider ~1/1000 (on the ...
Jochen K's user avatar
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3 answers
113 views

Inverting Amplifier

In the Figure shows what is the function of 𝑅0 and determines its value when V0 = −3V1 − 2V2.
NAMAN GARG's user avatar
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1 answer
120 views

About working of op-amp and making a potentiostat

I am trying to make a potentiostat for cyclic voltametry of molecules, using op-amps, an Arduino board, and LabVIEW program. Here is the circuit, from a paper from the Journal of Chemical Education. ...
Amju 's user avatar
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3 votes
1 answer
285 views

Virtual ground not close to ground in a current to voltage converter

I was hoping to get some feedback on a circuit I'm building. The schematic is as follows: Some description: This circuit essentially functions as a constant AC voltage source with current booster ...
summeriok's user avatar
1 vote
4 answers
199 views

Why does the current not divert in the inverting summing amplifier circuit?

Why is the current drawn from different sources in this circuit not diverted to other resistors? Why does current only flow through the Rf resistor?
Doğukan Karakaya's user avatar
0 votes
1 answer
69 views

I want to implement a 2-active crossover circuit with LM833 and amplify it using LM386 and now the problem is I couldn't understand the circuit [closed]

I can understand up to certain level that we used a buffer, low pass filter but I can not connect with circuit and coming to components we used 120 Ω, 6.8 nF for active crossover with power supply + ...
Yuva Praneeth Reddy's user avatar
2 votes
1 answer
220 views

Difference in inverting and non-inverting integrator

I am trying to simulate the step response of an inverting integrator and a non-inverting integrator. However, in the inverting integrator's output (blue plot), I see an initial overshoot in the ...
P T Nandh Kishore's user avatar
9 votes
3 answers
1k views

Is it misleading to say a common emitter amplifier is “out-of-phase”?

I now understand that a common emitter amplifier produces an inverted amplification. I am asking this question because for a bit, I was hung up around the frequency with which I heard it explained as ...
shafe's user avatar
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0 votes
1 answer
158 views

Decrease in bandwidth of inverting opamp

The bandwidth of inverting opamp is lesser than non-inverting opamp. If both configurations have equal closed loop gain and also Gain-Bandwidth product (GBW) for opamp is constant for both cases (...
MAJID AHMAD's user avatar
6 votes
3 answers
1k views

What's the point of Vcc and Vee closed loop in op amp inverter

I am trying to explain circuit in details, but I can't understand why do we even connect Vcc and Vee or V+ and V- in these inverting amplifier by C3 capacitor.
Warrant One's user avatar
11 votes
4 answers
2k views

Inverting op-amp problem

Down below is an inverting op-amp circuit with a capacitor C connected to the non-inverting input. I have to find the voltage at point A and express it using vin, C and R. I tried to solve the ...
kauselis3000's user avatar
1 vote
2 answers
94 views

Inverting op-amp unexpected voltage shift

I'm trying to create an op-amp circuit that attenuates a 5 V input signal down to a 1 VRMS Vout signal (1.414 V Vout). I need to shift the output signal by 2.5 V so that it can be fed into a unipolar ...
tpalmer345's user avatar
1 vote
0 answers
37 views

Control scheme to regulate Vin using a Buck regulator

I am trying to create a control scheme that allows a buck regulator to regulate its input voltage instead of its output voltage. I'm trying to make an efficient shunting regulator. My current approach ...
reconchris's user avatar
1 vote
1 answer
101 views

Why isn't my output voltage fully amplified?

I'm trying to design a circuit with A_v = -20, a swing of +/-2 V, an input resistance of 5 kΩ, and a corner frequency of 3 dB at 100 Hz. I did the following calculations to get R_E1, R_E2, R1, and R2. ...
zenizenitsu's user avatar
4 votes
3 answers
486 views

How does this rectifier work, since the op-amp input is 0 V?

Consider the rectifier below. Both inputs for the op-amp are 0 V. There are two diodes, that only allow current if the potential difference over them is above 0.7 V. Also, V1 is a sinusoid. I don't ...
ludicrous's user avatar
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3 votes
3 answers
652 views

About "Always inverting except when you can't" of OPA

Recently, I read here: Always inverting except when you can't Always adopt inverting, the reason for which is that noise can be reduced. Why? Could anyone explain in detail? I also have a problem. ...
curlywei's user avatar
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2 votes
3 answers
433 views

What is the purpose of this op-amp topology?

I have encountered this topology. As you can see, there is a constant 3.5V voltage source connected to the non-inverting op-amp input. It's clear that this is an inverting op-amp ampifier but I couldn'...
Electronx's user avatar
  • 756
2 votes
6 answers
282 views

Why can we deduce certain voltages from the op-amp?

I am learning about ideal op-amps. One of the main characteristics of this device is the infinite open loop gain, which means that we can deduce that the 2 input voltages are the same as \$v_2-v_1=\...
Riccardo Caiulo's user avatar
9 votes
2 answers
521 views

Unwanted DC offset at the input of inverting op-amp

I'm designing an envelope generator for a sort of mini synthesizer I'm currently working on. I want the envelope signal to evolve (rise or decay, depending on the SPDT switch) only when the switch (...
Javier Soto's user avatar
4 votes
4 answers
632 views

Block diagram of inverting amplifier

I want to draw the block diagram of a generic inverting amplifier. simulate this circuit – Schematic created using CircuitLab Question: What is the actual block diagram for an inverting ...
Carl's user avatar
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0 votes
1 answer
139 views

UPS for battery with minimum quiescent current

I am powering a PIR sensor which has minimum 3.4V of VCC and 70µA supply current with parallel Li-ion batteries and I want to switch on a boost converter when battery voltage goes below 3.5V. But the ...
CaveScientist's user avatar
0 votes
1 answer
245 views

How to calculate voltages in op-amp circuits?

I don't know how to solve the following problems; I don't even know what the best way to start solving them is. Can someone help me with the calculation steps so I can then try to solve them on my own?...
VfB Stuttgart's user avatar
0 votes
3 answers
640 views

How to correctly measure the bandwidth of an amplifier with gain from its bode-plot?

I have an amplifier with the following frequency response: It is an inverting amplifier with a gain of about -12. I would like to know what would be the correct approach for identifying its bandwidth....
Ching Chung's user avatar
0 votes
2 answers
147 views

0 dB Bode plot as a reference in an academic paper

I want to compare the calculated bode plot of an inverting op-amp with the simulated one, on the 1 mHz-200 kHz spectrum. As expected, theoretically there is no stray capacitance on the circuit above, ...
Gabriel Santos's user avatar
2 votes
0 answers
453 views

How to choose component values for a JFET common-source amplifier?

I am trying to design a simple common source jfet amplifier using a J109 transistor. I'm using the J109 datasheet and equations from the book Electronic Devices by Thomas L. Floyd. The issue is that I ...
Matthew_R's user avatar
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0 votes
1 answer
55 views

Dupicate LFO Signal and Invert, keeping MAXs and MINs

Im working on a Dual LFO with "Depth" and Rate controls. I already got the "root" LFO signal working and if I do this, I can generate the LFO swinging from 0v to 9v... and with ...
ElectronOne's user avatar
1 vote
0 answers
430 views

Designing a guard ring for a transimpedance amplifier

I am at that stage of a PCB design where I need some guidance on guard rings. The Application: The application is a photodiode circuitry (using a pin photodiode and transimpedance amplifier.) The ...
LabMat's user avatar
  • 161
5 votes
3 answers
971 views

Why does the thermal noise of this large resistor not contribute to the input noise for this JFET-input inverting amplifier?

I'm interested in building a low-frequency, low-noise, AC-coupled preamplifier (mostly for measuring the noise of very quiet linear regulators). Several existing designs that I've seen use a matched ...
MattHusz's user avatar
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0 votes
3 answers
409 views

What type of op-amp configuration is this from a PLL circuit?

Can someone help me to understand this attached op-amp model? We are using it in an HMC3716 PLL circuit. We don't know how it works, exactly. Is it an integrator or a differentiator?
Dinesh 's user avatar
3 votes
2 answers
1k views

High output impedance piezo guitar pickup is better attenuated by a shunt capacitor than an inverting opamp attenuation circuit

The circuit below is meant to attenuate a high output and high output impedance piezo electric guitar bridge pickup -7 dbV. The circuit models both the pickup output impedance and load of the cable ...
p-we's user avatar
  • 55
5 votes
5 answers
1k views

How to find the gain of an inverting amplifier in terms of feedback?

I have been struggling to answer this question from The Art of Electronics where it asks me to find the closed loop gain of a non-inverting amplifier in terms of feedback and says that the derivation ...
Random person's user avatar
7 votes
5 answers
859 views

Amplifier with selectable inversion?

Two inputs: Signal: 0-5 volt analog voltage Direction: Standard TTL logic Output: A single analog voltage from -10 to +10 volts When Direction is low, the Signal is amplified and inverted, so that ...
James Newton's user avatar

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