Questions tagged [non-inverting]

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5 votes
4 answers
343 views

Single-supply non-inverting op-amp for summing DC voltages at unity gain

Is it possible to use this single supply, non-inverting, summing op-amp configuration to sum multiple arbitrary DC voltages at unity gain? I've used the inverting summing op-amp config on bipolar ...
1 vote
2 answers
113 views

Powering a negative resistance converter with an Arduino power pin

I want to build a negative resistance converter and the only voltage source I have is a 5 V Arduino power pin. I am afraid the reverse current (Is) flowing through the power pin will destroy my ...
3 votes
1 answer
347 views

Is this the correct way of making a non-inverting optocoupler?

Requires to read 24 V input signal, and output to an Arduino as 1, at the same time it lights up the LED indicator. Is this circuit viable?
2 votes
3 answers
196 views

I have to find the relationship between Vout and Vin

Can someone use this picture as an example of how to systematically solve/calculate this problem? My teacher has written terrible, inconsistent notes, and now I'm confused for which formulas to ...
  • 59
6 votes
5 answers
860 views

Non-inverting op-amp

Why is resistor R1 connected to the inverting terminal of the op-amp in a non-inverting op-amp configuration? What will happen if we replace it with a short circuit?
  • 81
9 votes
6 answers
2k views

Why do we need R1 in a non-inverting op-amp?

I am quite new to learning op-amps. What is the purpose of putting R1 there? Does this have any meaning in the design of a microphone amplifier? I read about this from another answer, which says that ...
  • 91
1 vote
3 answers
144 views

Why doesn't this op-amp schematic work?

If I use just the first-stage op-amp it works, but the output from the first stage is 2.5 V. If I give it some signal the output will be 2-3 V. In the second stage I use a voltage divider and the ...
0 votes
2 answers
78 views

Non-inverting amplifier with stable gain

I'm working with a LM358 op-amp as a non-inverting amplifier to get a 0-24 V output from a 0-5 V input. When the input is 1.5 to 5 V, the gain is 4.8 which is OK (set by resistors), but below 1.5 V ...
3 votes
3 answers
449 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. ...
  • 583
0 votes
1 answer
97 views

Why is my op-amp giving same output for low voltages? [closed]

So I am trying to make analog output 0-10vdc with my esp32 microcontroller. I have read that esp can give true analog voltage cause it has DAC so my plan is to connect one of esp32 DAC pins to non ...
  • 11
2 votes
3 answers
162 views

Is hysteresis needed for this non-inverting comparator?

I’m trying to figure out if the following comparator circuit (TL331) would be reliable in the following application, or whether I would need to add anything, like hysteresis. To explain the ...
1 vote
1 answer
52 views

Texas Instrument OPA192

I'm examining the datasheet of the OPA192. When the inverting input of op amp tied up the op amp output and if the non-inverting input of op amp had been floating, what would have happened the op amp ...
  • 43
0 votes
2 answers
97 views

How does input resistance cause phase lag in the output in a voltage follower circuit?

I was solving a problem related to voltage follower in Fitzgerald's Basic Electrical Engineering, 5th ed., pages 458-459. The op-amp characteristics are (respectively open loop gain, open loop ...
1 vote
5 answers
962 views

Calculating the relationship between Vout and Vin in a non-inverting op-amp

Circuit: I have to determine the relationship between Vout and Vin. When analyzing the circuit I realized it was quite similar to a non-inverting op-amp circuit. I know from my past homework that I ...
  • 95
0 votes
2 answers
79 views

High output voltage from non-inverting amplifier without input signal

I bought an LM358 amplifier module to boost the input signal of 0-1 Vpp 20 kHz sine signal to 0-3 Vpp 20 kHz sine signal (gain of 3.) I tested the circuit with the input pin (non-inverting pin) ...
  • 21
5 votes
2 answers
450 views

Thermocouple circuit not outputting expected values

My application requires 11 thermocouples to be sampled and logged. Below is the circuit diagram, containing a differential and common mode filter, non-inverting amplifier (gain 111) and a second order ...
  • 73
0 votes
2 answers
83 views

AD8065 Offset problem

I'm an electronic engineering undergrad and your discussions helped me a lot. As a project, i was instructed to design the front end for a data acquisition system. The specs as below. Supply +/- 5V ...
2 votes
2 answers
101 views

Non-inverting amplifier isn't amplifying my signal

I am using a non inverting amplifier (shown below). For the opamp, I am using TL084, and I am using 12V single supply. I am getting an output of 11.20Vdc even though the input is 1.06V sine wave. I ...
  • 319
4 votes
4 answers
732 views

Why do you suppress the input when finding the output impedance of an opamp circuit?

In most derivations of the output impedance of an (non-ideal) non-inverting opamp circuit, the input terminal is grounded (e.g. page 5/6 here or page 76 here). It also seems to be a common procedure ...
5 votes
2 answers
210 views

How to calculate the gain of a non-inverting opamp with a transistor?

I have a question about this circuit. How do i rearrange the formula to calculate the voltage gain of this opamp with a transistor: I know the formula for the gain of a non-inverting opamp like in ...
  • 53
2 votes
1 answer
158 views

What will be the output of a single supply voltage follower circuit if negative voltage applied to the non-inverting input?

I am providing 1.8 V as supply in a single supply voltage follower circuit. Now my concern is if I put negative voltage (Range -1.3 V to -500 mV) in the non-inverting pin, what will the output from ...
  • 109
0 votes
1 answer
72 views

Amplifier clipping output signal [closed]

I constructed a noninverting amplifier with a sine wave input (0.5 Vpp) and observed an output signal that was clipped equally in both the positive and negative regions, to about 2.5 Vpp. I tried to ...
0 votes
7 answers
371 views

How does this op-amp config work as a voltage follower?

I've checked a couple of books and the internet, but every source just tells me it's a voltage follower, and not why. Without any resistors, I'm having trouble applying the 2 golden rules of opamps (...
  • 697
2 votes
1 answer
844 views

Range of feedback resistor value in non-inverting op amp

Is there any limitation for the range of the feedback resistor in a non-inverting circuit? What happens if I choose feedback resistor very high or very low? What is wrong with choosing a 10M ohm ...
  • 37
0 votes
2 answers
181 views

How to make my signal square without using two MOSFETs (and inverting it twice?)

I am trying to extend an existing solution to decode a specific signal (solved here for 1200bps speed: http://hallard.me/demystifier-la-teleinfo/ - article in french.) A 9600bps signal comes from a ...
  • 111
0 votes
2 answers
329 views

Design methodology for non-inverting summing op-amp

I'm trying to design an op-amp circuit to sum up four voltages by using a non-inverting summing configuration. You can see it in the circuit below, though for illustration's sake, the resistor values ...
0 votes
1 answer
307 views

Preventing op-amp outputs from affecting one another

I built this op-amp circuit that takes in 4 inputs and outputs 3 sums by using op-amp adder and difference circuits to achieve a gain of 2x. In a simplified circuit, I boiled it down to the bare op-...
4 votes
2 answers
475 views

TL071H unity gain buffer output voltage drops to zero when input near to zero

When the input voltage is smaller than 300 mV, the output voltage drops to almost zero. When it is above 300mV, the output follows the input. Why? If there is any discrepancy between input and output, ...
  • 190
2 votes
3 answers
204 views

Amplify DC signal: how to deal with real life problem ==> output is close to Vs when input signal too small OK otherwise

Hi I believe this problem must be classical and well known but I cannot find a place where it is specifically discussed: I have build a simple non inverting 2X amplifier following exactly the ...
  • 181
4 votes
2 answers
279 views

Why are low values of resistor in non-inverting configuration of opamp causing gain peaking?

I am trying to simulate frequency response of TLV07 in non-inverting configuration for gain 10 as shown below: The frequency response shows peaking as shown below: It is worse for smaller values of ...
2 votes
1 answer
145 views

Why does current noise flow through the parallel combination of R1 and RF in a non-inverting opamp?

I am following this reference for noise calculations of a non-inverting op-amp. I am not able to understand why the equivalent resistor is the parallel combination of R1 and RF as shown below: I ...
1 vote
1 answer
152 views

Why is the op-amp not able to amplify this voltage? It's a straight-forward non-inverting configuration with ideal op-amps(LTSpice simulations)

So I have the following configuration (pretty straight forward right?) But following are the waveforms of V_induced(the voltage to be amplified) and V_induced_amplified. As you can see, the voltage ...
10 votes
6 answers
6k views

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?
0 votes
2 answers
109 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 ...
  • 71
1 vote
1 answer
280 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 ...
0 votes
2 answers
193 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 ...
  • 145
0 votes
2 answers
166 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 ...
  • 143
3 votes
3 answers
195 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 ...
  • 567
2 votes
2 answers
1k 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 ...
0 votes
0 answers
262 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 ...
0 votes
1 answer
177 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 ...
0 votes
1 answer
62 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 ...
0 votes
1 answer
36 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 ...
0 votes
1 answer
246 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 ...
  • 103
2 votes
1 answer
87 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 ...
2 votes
1 answer
121 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 ...
0 votes
2 answers
289 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 ...
-1 votes
2 answers
699 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 ...
0 votes
3 answers
488 views

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

Also is it actually zero or just very low?
  • 3
1 vote
1 answer
763 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 ...
  • 163