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37 views

calculate the ouptut of two operational amplifiers in a series

i want to calculate Vs which is the output of this circuit simulate this circuit – Schematic created using CircuitLab so i just want to equation that can help me find Vs. please help me, ...
2
votes
2answers
74 views

How to analysis this Operational-Amplifier circuit?

This is a reference buffer circuit that make a single-end audio input to be the differential inputs for ADC. Circuit-1: It does not like typical Op-Amp circuit of the same purpose like below. ...
2
votes
2answers
260 views

Voltage output waveform of a differentiating amplifier

I have the following picture of the input and output voltage waveforms from a differentiating amplifier as shown below: And the schematic is as shown below: My teacher claimed that these waveforms ...
0
votes
1answer
30 views

What causes the necessity for a bias resistor for floating differential mode inputs?

Following excerpt from a text says Figure a and Figure b are equivalent: But in practice when Figure b is used we are recommended to use a 10k or upto 100k resistor between the inverting terminal and ...
0
votes
2answers
41 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 ...
1
vote
1answer
53 views

Differential (Subtractor) op amp with low pass filter

is it possible to have a subtractor circuit with a low pass filter in it? My thought is that I would have the possibility of doing that if I add a capacitor in parallel with R3. Is it actually ...
1
vote
1answer
89 views

BJT differential amplifier: What causes common mode voltage gain?

In any normal op amp, if it was ideal it would have a gain such that the output voltage would be However in reality this is not the case as there is a common mode voltage gain and hence in reality ...
0
votes
1answer
81 views

Ideal Op Amp Circuit

I have a question about the circuit below. I want to find Vo in terms of Vi. But I don't fully understand the principles about an ideal op amp's output. You will see my questions in bold at the bottom ...
1
vote
0answers
96 views

Differential Amplifier with TLC272 vs TL082

I have an LM2576-adj configured to step down 12V regulated output from a wall wart to around 5V-ish (see schematic). On the 5V output I have a 0.1 ohm sensing resistor (Rsc) to measure the output ...
-1
votes
1answer
91 views

Which load resistance is connected to generator U2?

I have this op amp and one of the questions says Which load resistance is connected to generator U2? This is my attempt but I can not confirm if it right. No it's not homework, it examples I'm ...
0
votes
2answers
64 views

Mathematical model for differential signals and relation with reality

i have a question and i hope is not that strange. i spend some time asking myself how people came out with the mathematical model for differential signals and why is this better in this way?! to be ...
0
votes
2answers
615 views

Virtual Short Concept in an Op-Amp

By virtue of the open-loop gain being infinity for an ideal op-amp, the two input terminals are said to be virtually shorted. Yet, the virtual short concept is only applied to op-amps in negative ...
-1
votes
1answer
100 views

Need to convert unbalanced to differential input OPAMP

I have the following filter after the DAC chip (currently with unbalanced outputs) working very well, but I need now to change the DAC chip. The new source has differential outputs. Is there a ...
0
votes
1answer
54 views

Can one voltage output from OpAmp read with two ADC inputs?

this might be a little silly question, but please advise me. I am trying to use two photodiodes (one for the absorbance measurement and one for the source of the light as a reference) and the voltage ...
1
vote
2answers
93 views

Gain problem of inverting opamp

I'm implementing the circuit in the schematic on the breadboard. Difference of inputs V1 and V2 is about 5mV. Differential opamp has gain of 17,4 Inverting opamp has gain of 26 First problem: I ...
0
votes
2answers
89 views

Is there such a thing as a fully differential line driver?

I'm looking to find something similar to the TI drv134 (http://www.ti.com/lit/ds/symlink/drv134.pdf), but then with differential inputs instead of single ended. Is there even such a thing? I can't ...
0
votes
1answer
71 views

Differential gain of an op-amp and feedback

In an op-amp, we know from basic electronic courses that vo = A(v1 - v2) Assuming large differential gain and finite output, we get that (v1-v2) is very very small, ideally zero. In a university ...
0
votes
0answers
74 views

How to measure external voltage differential with single ended ADC?

I would like to measure voltages from external circuits with the single ended ADC from an Atmega324. The plan is to power the Atmega324 with 3.3V and use a 1.024 or 2.048 voltage reference. The ...
0
votes
3answers
111 views

OPAMP - Current sense - unexpected behavior

I want to trigger an interrupt on an ATMEGA328P, when the current of a load is below a certain value. Therefore I designed the following differential amp circuit using an LM358 Below picture shows ...
6
votes
6answers
1k views

Comprehension problems with op-amps

The common differential amplifier takes two signals and amplifies the difference between these two signals. I am aware that this difference usually is around a few millivolts or microvolts so, to put ...
1
vote
1answer
159 views

Fully differential amplifier - adder?

I have two signal sources providing the same differential audio signal (VIN1 and VIN2). I want to sum those signals. The result (VOUT) shall also be differential. The idea is to take a fully-...
0
votes
2answers
79 views

Differential Op-Amp rising and falling error at zero [closed]

So I have a differential OP-AMP I've designed is essentially a cut and paste of the circuit seen below. simulate this circuit – Schematic created using CircuitLab I'm using it to track the ...
0
votes
2answers
632 views

Strange Behaviour Using LM358 Op-Amp as Wheatstone Bridge Difference Ampliflier

I've been working on building a circuit which uses a wheatstone bridge to find the value of a resistance temperature sensor (Danfoss AKS 21) and then passes that to a differential amplifier the output ...
0
votes
1answer
302 views

Differential op amp to measure negative current flow through shunt (Rails set to 0 and 5v)

Note* I have done some searching and though there are related topics to this one, this one is unique and I think it warrants its own Question, especially as asking additional questions on another ...
16
votes
2answers
3k views

Review request: DIY DC to 50MHz differential oscilloscope probe

Given the cost of proper differential probes, i've decided to make my own. The requirements are: DC to 50 MHz 3db bandwidth A few selectable input voltage ranges, from 3V pk-pk to 300 V pk-pk ...
0
votes
2answers
132 views

Need help with instrumentation amp behaviour

I was wondering if someone could help me understand why this instrumentation amp isn't working the way I think it should. The amp is an INA155. My intention is that at if a voltage (positive or ...
0
votes
2answers
309 views

Issue with bipolar to unipolar opamp circuit

i want to measure ac voltage.For that i need to shift an ac differential voltage (+1.23/-1.23 across R20) to 0v - 2.5v range for a unipolar adc.The R1,R21,R22 divides the voltage and gives +/-1.23v ...
3
votes
3answers
267 views

Offsetting a differential amplifier to remove the need for a dual supply

I'm developing two similar circuits that will enable me to differentiate the X and Y coordinates from a segmented photo-diode (Four segments). These coordinates will be dependent upon the position of ...
0
votes
4answers
397 views

How to apply 180 degrees out of phase signal at inputs of differential amplifier in laboratory when only one function generator is provided in lab?

In this differential operation experiment, two input AC signals have to be applied to the bases such that they are 180 degrees out of phase with each other, but I am not sure how to invert an AC ...
0
votes
0answers
35 views

Modelling this differential ended system for SPICE simulations and grounds

Considering above illustration, imagine a voltage measurement by a voltmeter where the voltage is coming from a differential output device i.e a device which sends mirrored voltages according to its ...
0
votes
0answers
77 views

Multiple differential amplifier

I have a small problem. I want to design a "multiple differential amplifier". With this, I mean a circuit that, given the inputs and outputs: simulate this circuit – Schematic created using ...
0
votes
3answers
3k views

Understanding the necessity of Tail Current Source in Differential Amplifier/Simulation (SPICE)

My objective is to understand the need of the tail current source in a differential amplifier. So, to understand the significance of current source, I tried simulating the behavior with and without ...
0
votes
4answers
163 views

THS4521-HT: Op-Amp giving negative differential voltage

Can someone help to explain where I get wrong with this schematics? I use a differential op-amp THS4521 and want to measure the differential signal coming from a pressure sensor (transducer). The ...
0
votes
2answers
557 views

Remove DC offset from differential output, rotary encoder

Op-amp in my circuit is accepting differential sinusoidal signal, that swings around 0 V with 1 Vpp. It is configured as a comparator - swings to upper rail when the signal is positive and swing to ...
2
votes
1answer
279 views

Trans-impedance Amplifer with a Fully-Differential Amplifier

I'm designing a trans-impedance amplifier (TIA) for a fairly fast Avalanche Photodiode (APD), to amplify pulses of 1mA that last few nanosecond. I found a solution that have just enough bandwidth with ...
0
votes
0answers
43 views

Variable differential amplifier

I made this scheme: simulate this circuit – Schematic created using CircuitLab Gain of this differential amplifier is constant and equal to 2. I would like to have possibility to substract ...
1
vote
1answer
404 views

What if you alter a differential amplifier by giving it a positive feedback rather than a negative feedback?

Figure 1 In the above Image 1, you see is a differential amplifier . It has a negative feedback as required. Now take a look at figure 2 below. Figure 2 Lets take a look at figure 2. Now that I ...
0
votes
1answer
216 views

Using ADS1252 In DIfferential mode

I am trying to use ADS1252 ADC with Arduino. I got following schematic from git of a breakout board for ADS1252 Now there is only one pin dedicated to input signal whereas I want to use this board ...
1
vote
1answer
96 views

Amplifier output goes haywire with load attached

I'm trying to create an op amp using FETs and BJTs. I need the gain to be over 500, currently without a load attached I have the gain about 1000. The input is a 0.05V sine wave, the output is ...
2
votes
2answers
404 views

What mathematical equation can be used to represent the output of this differential amp circuit?

My lecturer has gave my class a number of circuits to analysis and currently I'm having trouble with the following circuit: I am familiar with how to calculate an equation for the standard ...
0
votes
1answer
42 views

Differential Op Amp queston

So we are given the equation: Vout=Rf/Rs(V2-V1) I'm just wondering how would we solve it when the Rf/Rs are different values like they are in this circuit: simulate this circuit – Schematic ...
0
votes
2answers
258 views

Is there an amplifier voltage limit for the input signal even if the differential voltage is small?

I am building a simple current sensor. The amp says the maximum differential voltage is 5V. I'm not getting more than 1V in differential voltage at the moment. Is it safe to test differential ...
5
votes
1answer
485 views

Difference Amplifier with 3 Op. Amp. How to analyze it?

I have to demonstrate, in the following circuit, that \$ V_o= \left( 1+\frac{2R_2}{R1}\right)(V_2-V_1) \$ if the Pot is in the halfway. I know that the circuit inside the pink block its a Buffer for ...
1
vote
0answers
542 views

Sallen-Key with fully-differential output — options?

I have a single-ended audio signal that I want to low-pass filter and convert to differential (with GND as the OCM voltage — that is, when one output is X Volts, the other output shall be −...
5
votes
3answers
297 views

Efficiency of obtaining differential signalling from a single-ended manufactured transducers

This will be a conceptual question. I'm sometimes dealing with data-acquisition of transducers, like strain gauges, accelerometers ect. sort of sensors. Most of these sensors have their own precision ...
0
votes
2answers
1k views

Amplifying an audio signal with an op amp

I'm trying to build a pretty basic color organ, but i ran into a problem and I can't seem to find the solution to my specific problem. I built this circuit (using a 3.5mm jack connected to a phone or ...
1
vote
2answers
366 views

Can I just use one end of a differential op-amp ? (ie use differential op-amp as a single ended op-amp)

I found this awesome op-amp I can use which is super cheap and super fast (NE592D). Unfortunately, it has differential inputs and outputs. I can probably deal with the differential inputs, but how ...
1
vote
3answers
121 views

Circuit for connecting externally power instrument to MCU

I have externally powered instruments that I need connected to the ADC inputs of an MCU. They output 0-5V analog, and the MCU accepts 0-3.33V. There is no guarantee of the voltage difference in ...
4
votes
1answer
213 views

Fully differential opamp with weird behavior

I have a fully diffrential opamp that is configured like seen in the below picture: I have a series of Frequency sweeps (differently scaled input) that I performed and measured with a VNA. The weird ...
0
votes
2answers
364 views

problem with differential amplifier output ..not getting expected voltage at output i.e( V2-V1)..what is wrong here?

i have made the following differential amplifier but facing problem with this differential amplifier here i am expecting 7v i.e.(V2-V1) at output but only getting 4.999V .what is wrong here ?