# Questions tagged [non-inverting]

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### Why put a resistor in series with the positive terminal in a non inverting op-amp circuit?

I've tried to find the answer, but failed. Why do we add R1 in series with the positive terminal for a non-inverting amplifier? What is the best value we can assume or choose for it?
2answers
54 views

### non-inverting current sense op amp output unstable during the measurement

I would like some advice on how to solve the following problem. The following circuit is motor driver with current sense circuit. The circuit run motor at cca 30mV when is not under load, but when the ...
1answer
60 views

### Stereo channel strip based on NE5532

I want to build a stereo channel strip, using the NE5532 IC. It should feature 2 mono inputs with volume control, mute switch and pan control going to a stereo output with unity gain. In the schematic ...
2answers
42 views

### Am I measuring the Op-amp MCP6004 IC output voltage correctly using Arduino

Right now I am testing an MCP6004 Op-amp IC. A sensor in my main circuit going to give me a signal in the range 0-0.5 V max. So, I want to amplify this in the 0-5V range so that my Arduino reads it ...
2answers
66 views

### Motion Sensor Design

I'm trying to design a motion sensor alarm. If there is movement in my house, the motion sensor will send out a signal which will be connected to an alarm that will make a loud noise. I'm currently ...
3answers
156 views

### How to analyze this opamp circuit?

So with the following circuit (currently studying for an exam): I am able to get V- just through the voltage divider composed of 2R and R at the non inverting terminal. However, once there, I am ...
2answers
112 views

### Non-ideal Non-inverting op amp

This is probably more of an algebra question. I do not understand where the "1"s come from in equation 1.10 given the much simpler voltage divider equation in the line just above it. And why ...
0answers
67 views

### Amplify 1kHz sine wave from AD9833 DDS using LMH6609 operational amplifier

I'm trying to amplify a 1kHz sine wave signal from the AD9833 DDS chip (0.6Vp-p) to a more usable level (6Vp-p) for a sort of function generator. I plan to work with higher frequencies as well. So I ...
1answer
71 views

### Non Inverting Op Amp output near power supply voltage when input voltage is at 0V

I have a simple non inverting op amp circuit. I am using this to amplify a DC voltage. The positive input voltage will vary from 0V-5V. My problem is that regardless of the input the output is about ...
1answer
54 views

### Why does my single-supply non-inverting amplifier produce a wierd shape (depending on earphones)?

I built this circuit: It is based on this design for a single-supply non inverting amplifier: When I tested my output waveforms with earphone A I got normal results: When I used earphone B, I got ...
1answer
34 views

### How impedance levels affect a non-inverting amplifier?

I need help understanding what the highlighted section means. I mainly want to understand how it determines the current drain when using difference resistance to get the same gain, and how it affects ...
0answers
20 views

### How would you calculate the input impedances of these circuits? [duplicate]

How would you calculate input impedance of this circuit? I have tried and obtained these calculations for 1.3, but apparently my teacher told me that I am supposed to ignore the 2 10k resistors. This ...
1answer
42 views

### Combining inverting and non inverting opamps

I have a circuit: Assuming the op-amps are ideal, how do I derive an expression of Vout in terms of A and B? I set B to 0 and worked out that the output of the opamp connected to A is 9A, and by ...
1answer
45 views

### Inverting Amplifier Circuit using Single Power Rail

For my homework, we are supposed to simulate an inverting and noninverting amplifier using a single supply and the LM324 opamp. I built the inverting amplifier using a voltage divider, but my output ...
1answer
77 views

### Op Amp Selection Help for Rail/ Rail IO

I am looking for an operational amplifier which will fit my requirements. My circuit consists of two cascaded non-inverting amplifiers.I have a classical non-inverting setup.The minus pin of both ...
2answers
67 views

### Problem in controlling the device temperature using an op-amp

OBJECTIVE: I have a device to which voltage is applied and this voltage has to be controlled according to the temperature detected by the thermistor that is placed on the device. If the temperature of ...
2answers
167 views

### transfer function of non-inverting op.amp circuit

I am trying to find the transfer function H(s)= Vo(s)/R2(s) but i am struggling to get it. I am assuming an ideal op-amp. V+=V- and that no current flows through the pins op the op.amp. simulate this ...
3answers
208 views

### Why is the output impedance of a non-inverting op amp zero? [closed]

Also is it actually zero or just very low?
1answer
228 views

### Op amp output voltage offset too high

While building an opamp based non-inverting amplifier for my project I noticed that it always has some considerable output voltage despite having the input at zero. To verify that problem I built the ...
2answers
96 views

### Difference between two gain +1 op-amp topologies

I've got two differential driver circuit designs that take a single ended input and provide as output a buffered pair of +1 and -1 times the input and I'm struggling to understand the difference ...
1answer
634 views

### NE5532 opamp on amplifier circuit

The picture below is named as headphone amplifier on the internet. My goal is not to do "headphone amplifier". I want to design an analog frontend with a bandwidth of 10 MHz for ADC input. This ...
6answers
6k views

### Single supply opamp with AC coupling

I am trying to make an amplifier with an opamp, using a single supply. I found lots of ressources online. This response was very informative and I tried to simulate this circuit. Let's say that I ...
2answers
82 views

### Op amp output DC operating point variation with load current

Consider a cmos op amp in non inverting configuration. For a small load current, we expect the output DC voltage to be the input DC voltage multiplied by closed loop gain. As the load current is ...
1answer
49 views

### Line input circuit

I'm trying to design an unbalanced line input for an audio device using a single supply. I would like the input stage to provide variable gain between 0 and 2. This is what I have come up with so far:...
1answer
87 views

### Limit the current draw from Op-Amp

Following up on this question I redesigned my circuit with the suggestions from the comments (see comments from @Andy_aka). I want to drive the output of the opamp between 0-24V with an Vin = 0-10V. I ...
1answer
176 views

### Why is the output signal greater than the input signal in this voltage follower circuit?

I have implemented this circuit on my breadboard. The voltage waveform at point A and B in the circuit attached below should be equal because it's a voltage follower, but in my case, after ...
1answer
285 views

### Is this Non-Inverting integrator correct?

I've seen time again the formula for an inverting integrator. I was wondering if I could swap the configurations on the inverting and non inverting inputs of the op amp to make the circuit a non-...
2answers
146 views

### What is the gain in a non-inverting amplifier

I am unsure if I am tackling this problem correctly. The input signal is connected to terminal E4 and the output signal is observed at terminal E9 What is the voltage gain when E1 is connected? What ...
3answers
169 views

### Non-inverting amplifier with negative supply rail

simulate this circuit – Schematic created using CircuitLab The formula Vout = Vin * (1 + R2 / R1) is not valid for this case? because for example I'm feeding ...
2answers
92 views

### Calculation of noise in Non inverting Op-amp circuit

I have this non inverting op-amp circuit: I would like to calculate the output with the Op-amp noise impact. I can easily find the voltage output, but only if I assume there is no noise. How to do ...
2answers
1k views

### Non-inverting amplifier with variable gain from 1 to 15

I need to design a non-inverting amplifier with gain from 1 (unity) to 15. From what I read, in theory this can be achieved by using a pot as the feedback resistor, but in practice this will only work ...
1answer
86 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 ...
1answer
237 views

### Non-inverting op-amp saturating incorrectly

Background Hello, I'm trying to amplify an audio signal using an LM324N in a non-inverting configuration. I'm not trying to build an audio amplifier to drive speakers, I just need to amplify it a bit ...
1answer
868 views

### Floating input in Op-amp Readout Circuit?

I was analyzing this circuit diagram in a thesis about a capacitive EEG electrode. The author talks about a flaw in the design where there is a "floating analogue input" that is causing the op-amp to ...
3answers
1k views

### Non-inverting amplifier ; Single supply ; Bipolar input

I am working on the non-inverting amplifier using a single supply, which can amplify bipolar input signal. Non-inverting amplifier is working fine without any issues, only the negative portion of the ...
3answers
440 views

### How to add a low pass filter to this non-inverting amplifier circuit?

I've come up with this simple circuit as an amplifier before an 8bit ADC which receives audio signals. R2 is actually a variable resistor (pot.) of 100k. The circuit also biases the signal to VCC/2 ...
2answers
476 views

### Gain of Non-Inverting Amplifier Does Not vary with Resistor Values

I am trying to build a non-inverting amplifier using a LM7171 op amp, and I am implementing it with potentiometers as Rf and R2 so that I can smoothly control the gain of the amplifier (and easily ...
1answer
943 views