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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153 views

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 ...
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 (...
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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" ...
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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?
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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. ...
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209 views

T-network feedback of opamp [closed]

How are the output (Vo) and H(s) = Vo/Vin calculated in this schematic?
1 vote
45 views

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 ...
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=...
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1 vote
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 ...
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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 ...
1 vote
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 ...
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 ...
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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 ...
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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 ...
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1 vote
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 ...
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335 views

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 (...
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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 ...
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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 ...
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?...
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....
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, ...
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 ...
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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 ...
1 vote
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 ...
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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 ...
• 1,063
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?
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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 ...
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