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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.

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.

If the input is called \$x(t)\$, then the output \$y(t)\$ of an ideal (i.e. perfectly linear, with infinite bandwidth) inverting amplifier is:

$$ y(t) = - \; A \; x(t-t_d) $$

Where \$A > 1\$ is the gain of the amplifier and \$t_d > 0\$ is its propagation delay. The minus sign before the gain is what makes the amplifier inverting.

224 questions
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Why is Vbe a constant 0.7 for a transistor in the active region?

I'm going to take an example of a simple common emitter amplifier. Forget about biasing and things for now, but focus on the crux of this circuit. As how I understand it, a voltage between the base node and the emitter node is varied which is…
midnightBlue
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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 problem using nodal voltage analysis: (vin - va)/R =…
kauselis3000
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What is this circuit called, and what is it used for?

I analyzed this circuit and found that it's an inverting amplifier and that the impedance of the circuit goes to zero when the frequency of the input voltage goes to infinity. Does anyone know the specific name of this circuit, if it has one?
umutcankalayci
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What is the use for non-inverting input resistance in a negative feedback opamp?

Here in the Figure R5=50K. This resistor value is not in the equations to obtain output voltage, and in many tutorials non-inverting input is directly grounded without a resistor. What might be the reason to use it here?
user16307
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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 having an output that is “180 degrees…
shafe
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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 (SW1) is closed. The first part of the circuit (RV1,…
Javier Soto
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How does the compensation resistor in an inverting amplifier compensate for the input bias current?

I can't see how a resistor placed on a whole other input terminal has anything to do with compensating this input bias. i.e. the input stages are just the gates of transistors of differential stage. In this circuit, one of them is completely…
Mahmoud Salah
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Operational Amplifier with mixed feedback

So, I came across this circuit in a test, it's regarding the operation of an op amp with multiple (positive and negative) feedback, the circuit is as follows: I was asked to evaluate the following statements about it: 1. Does the Operational…
Archer Fuyyr
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Opamp stability given in not inverting configuration

If a datasheet (like AD828) says that an opamp is stable at Gain >2 (or reccomends to work with G>2, hence it is clearly not unity gain stable), what can we deduct about its stability in the inverting configuration at G=-1; G=-2 or G<<-2 (like in…
Gianluca G
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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 the original 0 to 5 volts becomes 0 to -10 volts…
James Newton
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Non-linearity of op-amp attenuator

I am having some trouble with an attenuator circuit as part of an automated test tool I am working on. As part of the design I need to attenuate a +/-10V input signal down to +/-5mV with some offset, I came up with the below circuit and implemented…
Hugoagogo
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Opamp Inverting Amplifier: The case of non-inverting input not being connected to ground

What is the relation between \$V_i\$ and \$V_o\$ when the non-inverting input is supplied with a non-zero voltage level? I have shared my formula derivation below, but I can't validate it since I can't find this special case anywhere on the…
hkBattousai
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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
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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 JFET pair with blocking cap and large resistor to…
MattHusz
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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 is straight-forward while it seems like anything…
Random person
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