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Questions tagged [input-offset-voltage]

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7 votes
5 answers
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Discrete op-amp small voltage offset

I have a design for a valve tester that previously used OPA445 op-amps to create the grid voltage - the grid circuit is just a 4.096 V I2C DAC running into the amp with a gain of -16.5, which means I ...
Oliver Gardiner's user avatar
1 vote
1 answer
41 views

Errors in measurement of Input offset voltage

I am reading AD application note MT-037 for input offset voltage measurement procedure. App note says , measurement will have small error induced due to input bias current . "For example, 2 nA ...
Ronnie's user avatar
  • 328
0 votes
1 answer
142 views

Getting offset in output voltage in OP07 circuit

I'm working on one OP07CD circuit, Application - this amplifier circuit used for amplification pressure sensor circuit & feeding output to microcontroller ADC input pin. Problem Statement - ...
Bhushan Waghe's user avatar
1 vote
5 answers
1k views

Op-Amp's offset voltage and bias current

The following Op-Amp is ideal, except of an offset voltage at the input : Vos = +-10mV, and a bias current: Ib = 10uA. I am supposed to find the value of R in order to compensate for the effect of Ib ...
Aleat's user avatar
  • 177
1 vote
0 answers
72 views

Cascoded op-amp: What practically limits CMRR and input impedance?

I am interested to better understand the practical limitations to input impedance and common-mode rejection ratio in cascoded op-amp structures. I already simulated quite a bit, but I am running into ...
tobalt's user avatar
  • 22k
1 vote
2 answers
152 views

How to estimate the DC error for this input and opamp?

I need to amplify a 0 to 2.5 V range DAC output to obtain a -5 to +5 V range final output and I have some of these opamps to use. In my case the DAC output to be amplified looks as follows: Looking ...
ty_1917's user avatar
  • 1,006
3 votes
4 answers
980 views

How is the input offset voltage a function of common mode voltage?

I don't know about the internals of a opamps, but is it possible to explain how a change in common mode voltage changes input offset voltage Voff? I'm asking because when the signal Vin is fed to the ...
floppy380's user avatar
  • 1,845
4 votes
3 answers
975 views

Does the input offset voltage of an opamp remain same after each power up?

If we have an opamp and we know the input output relation we can obtain a linear function even though there is input offset voltage. In the above situation as long as we know Vio, and since resistors ...
user1245's user avatar
  • 4,135
0 votes
3 answers
450 views

Op-Amp integrator with offset voltage output time function

I am studying the function of an Op-Amp integrator with offset voltage that is in the picture below: I have derived the output voltage formula myself, but I am not sure if it is correct. The formula ...
FriendlyNeighborhoodEngineer's user avatar
5 votes
3 answers
1k views

Which op-amp parameter indicates the minimum amplificable voltage?

I'm a newbie trying to measure μV-range voltages using cheap op-amps, with some software calibrations or error corrections, for education and practice. At first, I looked at some op-amp datasheets and ...
Tirdad Sadri Nejad's user avatar
1 vote
7 answers
445 views

Where has this current gone in my current-voltage converter?

Everybody knows what a "current to voltage" converter is, a basic application configuration for op amps. This is a very level basic question. See the picture. What is wrong? Have I missed ...
Antonio51's user avatar
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2 votes
1 answer
236 views

Op-amp offset voltage and capacitive coupling

About the circuit above, I can't understand from the row "VA=2Vos". If that's because most of the voltage between 1K ohm resistor and capacitor is on 1K ohm then I can't understand why VA ...
Greenbanana's user avatar
0 votes
3 answers
80 views

Operational amplifier input voltage [closed]

I give the same voltage to opamp inputs (AD 744) but the output depends on the Vcc value. Vcc voltage is 8.00V, the output voltage is going to 7.36. Vcc voltage is 6.00V, the output voltage is going ...
bimsara 's user avatar
-7 votes
2 answers
226 views

How to give op amp's negative supply a slight negative offset in a simple way? [closed]

I'm trying to go over the problem of the rail to rail limitations of my op amp to get a full reading range over a current sensor and I thought offsetting the negative supply just of the op amp IC ...
MikeLemo's user avatar
  • 155
0 votes
0 answers
132 views

Offset of amplifier input voltage of shunt current amplifier

I'm trying to build a 20A E load and decided to use a 0.01Ohm shunt for the current measurements and set so I needed to amplify the shunt voltage by 10 using the "rail to rail" AD4522-2. At ...
MikeLemo's user avatar
  • 155
17 votes
6 answers
3k views

How do professional designs compensate for offset voltage in opamps?

I am new to electronics and have been told in class to always add precision potentiometers to compensate for input offset voltages in opamps for signal conditioning. My concern is that this offset ...
Daniel Vela Jarquín's user avatar
0 votes
1 answer
164 views

DC offset in closed-loop ideal op-amp

It's from Sedra. It's about how the offset current messes with the input of an inverter. It's "easily seen", but no so for me. Can anyone explain to my "not easily seen" brain how ...
Leon Held's user avatar
0 votes
0 answers
123 views

Effect of op-amp's input offset voltage on stability of constant current load

I'm designing a simple circuit to have a constant current load with good short term stability. The exact current value is not important, as long as it's stable short-term (10 seconds). R1 is the load -...
axk's user avatar
  • 817
0 votes
1 answer
66 views

OA min/max input offset voltage

I want to build an instrumentation amplifier using MC33079 quad op amp, in page 3 of the datasheet it specified min and max input offset voltage: What causes the input offset voltage to increase?
ElectronSurf's user avatar
  • 2,366
1 vote
0 answers
135 views

How can I add an offset voltage at the input of an instrumentation amp?

I want to measure the voltage of an H-Bridge Sensor. However, due to the manufacturing process, the bridge has an offset several times larger than the useful signal (it can easily measured by ...
jjstcool's user avatar
  • 474
-1 votes
2 answers
58 views

Offset Voltage at Op Amp Inverting Terminal

I'm using ADA4350 as a transimpedance amplifier with various gains for feedback paths (30 ohms,3k,300k and 3 mega ohms respectively). When I give a constant current source of about 23mA as input to it,...
blazingcannon's user avatar
0 votes
2 answers
167 views

Input offset voltage, input bias current, input offset current of operational amplifier

Are operational amplifier parameters such as input offset voltage, input bias current, input offset current DC noise? Can I get rid of these noises by using a high-pass filter? If not, how can I get ...
mehmet 's user avatar
1 vote
1 answer
560 views

Opamp input offset voltage when saturation

I wonder, how to affect the input offset voltage of inverting amplifier when it's output in saturation? I'm changing gain with decreasing the value of R2. When the gain is greater than 5, output in ...
Berker Işık's user avatar
1 vote
1 answer
503 views

Definition of the offset voltage for a single-ended op-amp

Let's consider an op-amp: The book I'm reading says that, ideally, if the voltage difference between the two inputs is zero (thus vin1=vin2) then the output voltage should be zero. However, because ...
Stefanino's user avatar
  • 616
0 votes
3 answers
324 views

What is an external nulling "resistor"? [duplicate]

in the following datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/OP07.pdf Which is a OP07 a high precision ultralow voltage offset OpAmp, it says in the datasheet. ...
forthelulx's user avatar
1 vote
3 answers
427 views

I set up an amplifier (LF351) for a gain of 5.7, but it is saturating. Do I have to utilize the offset null pins?

simulate this circuit – Schematic created using CircuitLab The feedback network I am using is a voltage divider with 4.7K and a 1K resistor. The node after the 4.7K resistor is connected to the ...
Sal M's user avatar
  • 131
0 votes
3 answers
269 views

Opamp input offset voltage...common mode?

Looking at the datasheet for an OPA197 opamp, I see this: What is the circled expression trying to tell me? The common mode voltage is equal to the voltage at the non-inverting input minus 1.5 V ...
evildemonic's user avatar
  • 9,209
1 vote
3 answers
420 views

Offset voltage comes to saturation in coupling amplifier circuit using OpAmp with Gain=100

I did get in troubles with my student project circuit below! The purpose is to amplify difference between two inputs. Specifically, 20mV and 10mV are connected with input to get 1V at the last OpAmp'...
Thanh Nhon's user avatar
0 votes
1 answer
350 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 ...
D_Dog's user avatar
  • 453
1 vote
1 answer
867 views

How to compute DC offset of analog circuit?

I have an analog circuit which has an input voltage range Vin of 5V - 10V and output voltage Vout. One can assume that the circuit has been simulated and a DC sweep of Vin with a range from -10V to +...
Maxwell1919's user avatar
3 votes
0 answers
1k views

Comparing sine wave and triangular for spwm using comparator

i am trying to generate sinusoidal PWM by comparing sine and triangular wave. First i just tried to compare sine wave with reference voltage in order to check the working of op-amp. I get a problem ...
Bud's user avatar
  • 389
1 vote
2 answers
1k views

Input Bias Compensation Resistor Calculation for an Integrator

I have been reading the following tech note from Analog Devices that discusses designing an op amp circuit to compensate for the input bias current: https://www.analog.com/media/en/training-seminars/...
cosmikwolf's user avatar
0 votes
0 answers
63 views

How to solve practical OPAMP with finite differential resistance and finite offset current while other parameters can be considered ideal?

simulate this circuit – Schematic created using CircuitLab Ip(bias)=200nA rd=differential resistance=5Mohm a=infinite What should be its output? I am confused if I should consider negative ...
Buzz bee's user avatar
0 votes
1 answer
343 views

What is role of R9 resistor at input to OPAMP in this circuit?

I guess it has to something with offset nulling but not getting how .Circuit shown is of instrumentation amplifier.
Buzz bee's user avatar
1 vote
1 answer
835 views

Op Amp Input Offset Voltage vs Common Mode Voltage

I would like to use an op amp AD8618 for a design, and need the input offset voltage to be low. For this op amp it seems fine with maximum of 65uV, but looking at the charts on page 6 etc, it seems to ...
Himmel's user avatar
  • 81
1 vote
1 answer
37 views

sensor output level shifter

I am trying to read a map sensor with an ads1232 ADC. The Map sensor requires 0v(ground) and 5v+ and outputs 2.5v fluctuating +-2.5v depending on the pressure. The ads1232 can read +-2.5v but without ...
Adrian 's user avatar
1 vote
2 answers
300 views

opamp Vos bias resistor

In a simple inverting amplifier I've seen the below topology in my text book, where R3 is said to be R3=R1||R2. However, every time I see this, all three resistors are the same values! From Forest ...
Aaron's user avatar
  • 7,692
1 vote
2 answers
190 views

op-amp pin is sitting at high voltage (active low-pass filter)

I am looking at using the OP1177 to act as an active low pass filter. I need to smooth out a 20kHz signal burst with a minimum of 50 cycles to reach a voltage on the output to interrupt an ...
Hart22's user avatar
  • 361
0 votes
1 answer
519 views

Input offset voltage for microphone circuit

Does anyone know what's the input offset voltage (oscillated 2.5V) to the op-amp in the circuit for? From my understanding, the input offset voltage needs to be extremely small so that output DC ...
Taka's user avatar
  • 1
0 votes
2 answers
699 views

Supply Voltages for Inverting Amplifier

I want to use an inverting amplifier to linearly shift and convert a signal with voltage range -10...+10V into 0 ... 3.3V for an ADC of a microcontroller. I wanted to use the circuit presented in this ...
Geralt's user avatar
  • 17
0 votes
2 answers
2k views

OP-AMP DC offset compensation

I do not know how to compensate the DC-offset caused by the Input bias current. simulate this circuit – Schematic created using CircuitLab How to compensate the input current bias DC offset? ...
0___________'s user avatar
  • 2,585
2 votes
1 answer
2k views

Compensating for offset voltage in bridge measurement before instrumentation amplifier

I'm using an instrumentation amplifier (INA118) to measure the signal from a full bridge strain gauge (tension only, all 4 resistive elements are strain gauges, slow changing (DC) signal). I'm using a ...
Bales's user avatar
  • 43
0 votes
1 answer
665 views

input offset voltage of an op amp

How input offset voltage (2mV max) will effect input which is at 0.5mV and 0.5 to 5Hz frequency? The input voltage and frequency are of heart vibrations which will be very low.
rdeep's user avatar
  • 17
2 votes
5 answers
796 views

Do AC coupled inputs suppress voltage offsets in an op amp?

Background: I'm trying to build an AC coupled pre-amplifier that doesn't succumb to voltage offsets and input bias currents. The input signal has noise ~10 nV level, and I want a factor of a million ...
Enrique Mendez's user avatar
5 votes
2 answers
629 views

Strange voltage tracking problem with regulated power supply build

I'm building my own regulated linear DC power supply based on the Farnell L30 (service manual and circuit diagram here) and I'm sticking mainly to the original design with some modifications for parts ...
Buck8pe's user avatar
  • 1,694
2 votes
3 answers
5k views

Measuring input-offset-voltage of an opamp in sim and getting very different result in datasheet

With the definition of "input offset voltage" I wanted to find it in simulation for LM358 op amp. Here is the definition: "Input offset voltage is the differential input voltage that would have to be ...
user1245's user avatar
  • 4,135
0 votes
1 answer
413 views

Combined temperature coefficient of LM741 and trimmer pot for null offset

I want to use a 10k trimmer pot with a 250ppm/°C tempco for offsetting input offset voltage of an LM741 op-amp. Cermet potentiometer temperature coefficients partially answers my question. And the ...
Jodes's user avatar
  • 5,104