# 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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### How can I convert a very high positive DC voltage to negative DC voltage

I have a high voltage power supply which can power up to 30 kV with respect to ground. However, for my experiment (something like the one used in photocopier machines) I need a high negative DC supply....
34 views

### OrCad PSpice: Did I design the circuit wrong?

I keep getting 0 volts when I design this circuit but I was supposed to get a value of 1V at least. How I would be able to fix this circuit? The circuit that we were supposed to design was Fig(74)....
3k views

### Why does the input resistance of an inverting op-amp amplifier have to be high?

According to Sedra & Smith's microelectronics textbook, in order to avoid a loss of signal strength, voltage amplifiers are required to have a high input resistance, which I agree with. However, ...
38 views

### Limit current through Force Sensing Resistor

I am using an ICL7660 chip to provide a negative reference supply to an inverting op-amp set up for a Force Sensing Resistor (FSR). The minimum resistance of the FSR is about 1kohm, this means that ...
55 views

### 'Inverted' voltage follower with an opamp

I'm trying to figure out how I can achieve an 'inverted' voltage follower. That is if I'm feeding 1V I output -1V, if I feed 2V, -2V etc. I'm only going for positive tension to negative, I have +15 ...
110 views

### How to calculate $R_{\text{in}}$ in this circuit?

I know for an ideal inverting op-amp, the equation for finding gain would be $\frac{-R_1}{R_{\text{in}}}$, but how can I find $R_{\text{in}}$ in this circuit?
50 views

### inverting op amp unwanted DC offset

I want to use this circuit to generate a triangle wave from 100mv to 10v and an inverted wave from -100mv to -10v on triangle_inv. For my split rail supply, i'm using the VG1 circuit from this page ...
51 views

### Simulation of inverting Op-Amp

I am trying to build a circuit which is controlled from an analog input signal Vin to produce a -24V signal with >50mA output. My analog card can only produce ~10mA, therefore I generate the signal ...
63 views

### 3dB frequency of inverting amplifier

There is already a similar question in this website, but I still can't solve this. I have the following information: An inverting opamp with nominal gain -20V/V, DC gain 10^4 and unit gain 10^6Hz. I ...
73 views

### Input voltage range of amplifier

I had to design a circuit to work as an inverting amplifier. The circuit is as shown below, and in order to obtain Gain 5, input resistance of 30kΩ, R6 has to be a potentiometer of 100kΩ and the op-...
43 views

### Fourierspectrum of the output voltage of an real inverting amplifier

First a quick descripton of my circuit: The inverting amplifier amplifies by 20dB, the input voltage is a sinus signal with the Frequency 10 kHz and the peak to peak voltage is 200mV or 10V. The used ...
75 views

### Inverted Op Amp for Current Sensor Output

I'm having trouble understanding why the following circuit uses the inverting configuration rather than the non-inverting configuration for amplification. This design is from the Sparkfun Current ...
106 views

### Relationship between input and output voltage on a complex inverting integrator circuit

I am on my first semester of electrical engineering and I came upon an exercise where in the given circuit I have to calculate the relationship between the input and output voltages of the op-amp. ...
78 views

### Design of Low Pass Filter

So I have made a low pass filter and plotted the transfer function of it. However, I know I need to also use another opamp to correct the phase shifting/ gain. What design should be best to add on to ...
208 views

### 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 ...
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### How to invert one channel of phone output?

I want to connect phone output to a car radio. It has + and - inputs. When I connect left channel to the + input, there is good quality sound, but it's not as loud as CD player. If I invert right ...
78 views

### Single supply inverting OP amp. Problem: half signal at output

I have built a simple inverting amplifier circuit with LM4565 operational amplifier. But only half of the signal appears at the output of the circuit and the gain looks wrong as well. Could anyone ...
93 views

### Time constant of inverting amplifier, filter

simulate this circuit – Schematic created using CircuitLab I want to calculate the time constant τ of the filter. Can anybody help me?
293 views

### Can the output impedance on af op-amp be set to 50 ohm regardless of frequency?

I want to make a circuit with an output impedance of 50 ohms. I am dealing with negative photomultiplier tube pulses that in 50 ohm load look like in the picture below: I want to use the pulses to ...
62 views

### Finding Vout and Gain of a differential amplifier

I am given this figure below: And I am trying to find Vout and the gain. From looking at this source: https://www.electronics-tutorials.ws/opamp/opamp_5.html I have determined the gain to be 10k/1k ...
434 views

### 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 ...
225 views

### What is the difference between these two op-amp circuits?

I don't understand why when we design a proportional amplifier, the feedback has to be negative. When I run the simulation in simulink I get the same result for both circuits.
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### What would be the difference in the voltage transfer curves of this two circuits, assuming the op-amps are not ideal?

How does the resistor connecting the non-inverting terminal to ground affect the transfer curve?
338 views

### How can Vo = A(V+ - V-), if V+=V-=0? [duplicate]

We’re considering an ideal opamp here; so does that mean that Vo is infinity ♾ * 0 (A * (V+ - V-))? Thanks!
95 views

### Simulating a specific MOSFET circuit in PSPICE

I want to simulate this circuit in PSPICE (to get approximate output waveform ($v_o$)) simulate this circuit – Schematic created using CircuitLab Here, $v_{in}=0.2 \sin(wt) ,$ & ...
76 views

### Phase splitters/inverters using valves with directly-heated cathodes

I'm building an audio amplifier using Raytheon 6418 valves and I'm struggling with the phase splitter. The 6418 has a directly-heated cathode and I'm wondering what limitations this might introduce. ...
78 views

### zero AC gain of CMOS inverter

Why is the following AC analysis of CMOS inverter resulted in zero AC gain (vout/vin) ?
172 views

### What is function of the resistor in series with bypass capacitor in npn transistor amplifier?

I am new to electronics and recently I was learning about npn transistor as an amplifier. I tried to build one in ltspice XVII. This is my circuit diagram: but the output was not as expected as ...
145 views

### Op-amp problem, two inverting amplifiers?

So I stumbled across a rather strange ideal op-amp circuit that I've never encountered before. I've done enough problems regarding inverting amplifiers, non-inverting, summing, difference, and such, ...
232 views

### Inverted Pulse Generator

How to design a circuit (only using transistors) which takes 0V to 3.3V step at the input and generates a negative 1ms pulse at the output. ...
68 views

### Designing a Band Pass Filter

I need a band pass filter that only accepts frequencies from 1000 to 1400 Hz and then toggles the transistor. It has to work from .1 Vpp to 1 Vpp and rejects anything else. I have been testing this ...
108 views

### Inexplicable base bias

I have a common emitter amplifier on my breadboard (the same circuit as the image) with the following values: C = .01uF, R1 = R2=15k, RL = 5k, RE = 1k, and Vcc= 10v. The reason I have R1= R2 is I ...
92 views

### Unconnected Inverting terminal of op-amp to hold a steady voltage?

I recently completed my final for my first year electrical Engineering Subject and I have the image of the question above. I was really confused because it says when both switches are open, which ...
589 views

### Non-inverting output of transistor circuit (at NPN base) is 0.69V max. why?

I tried to make a simple NPN transistor inverter so that I can use the strobe line of the parallel port to store data in two separate flip-flop IC's. (74HC174 and 74HC574) The IC that data will be ...
117 views

### How do I determine the purpose of this op-amp circuit?

I have this circuit and I was asked to determine V2=f(V1) and V3=f(V2) which I determined below. The next step is to figure out what the purpose of this circuit is but I'm not sure how to do it from ...
304 views

### LTC6994-2 signal inverted and time delayed

I use LTC6994-2 to delay and invert input signal. I want 2s delay between input and inverted output. However, this is what I get on the output: Green waveform is input waveform. Output (Blue ...
122 views

### OP Amp bridge - any warnings?

In order to double output voltage swing I was going to use two OPA548 in difference configuration, connected to opposite inputs like this: I had one big concern about this circuit - that ground-...
399 views

### Resistor in the inverting terminal of the op-amp

I was studying the gain of an op-amp in both inverting and non-inverting configuration. In case of inverting configuration, the resistor is in series with the applied AC voltage. But in case of non-...
235 views

### Single Suppy Opamp for inverting amplifier produce negative voltage signal

i made an inverting amplifier circuit using CA3130, the supply just the positive voltage and GND for V- supply. the circuit is used for full wave rectifier because the signal is around 1 MHz and 500 ...
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### Canceling ambient sound [closed]

I've just moved into a new flat and I noticed that there is a lot of car noise coming through windows. I know, I could just close the windows, but that's a less interesting approach to a problem. So ...
84 views

### Noise Cancellation Project [closed]

I am working on a noise cancellation project and I am having problems with my design once I breadboard it and connect my 8ohm load. Design Notes: I am not applying/mixing any kind of signal into ...
787 views

### Design a circuit using 1 ideal op amp whose output is Vo = VI1 + 2Vi2 - 9VI3 + 4Vi4

So, I've been staring at this problem for several hours now. I've watched videos on summing amplifiers, and the like--but nothing seems to show how to use 1 op amp in a circuit that acts as both a non-...
652 views

### Problem with output swing in LM358

simulate this circuit – Schematic created using CircuitLab I am working on a battery charger with indicator. I am using a LM358 to compare the voltage of my battery with a reference voltage of ...
2k views

### Use of superposition principle for the inverting amplifier

My current understanding of the inverting amplifier goes as far as assuming the second golden rule: no current flows through the OpAmp. From here on, up to the end result of \\$ H(\omega) = -\frac{R_2}...
175 views

### Calculating voltage at non-inverting input of the op-amp

I am asked to calculate the voltage at the non-inverting input of the op-amp if v1=4.78V and v2=0v. I thought that the answer would be zero, as the voltage at the non-inverting input must be ...
117 views

### Transfer function of Operational Amplifier

I am trying to solve the following operational amplifier circuit to get its transfer function. I have tried two different approaches, one is elementary approach by finding V- and V+ and equating ...
95 views

### Negative feedback sustainability

If positive feedback makes output exponentially increase and cause instability in an opamp then why doesn't negative feedback make output extremely small and cause the system to collapse?
51 views

### Shaping negative pulses to positive ones pt2 [duplicate]

I asked a questing a few weeks ago, and asked a follow up question as a answer to that post? Apparently that's not allowed, so I am making this post instead. The question is based on this thread: ...