Questions tagged [input-offset-voltage]
46 questions
16
votes
6 answers
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 voltage is inherent to the opamp IC and is different…
Daniel Vela Jarquín
- 189
- 1
- 4
5
votes
3 answers
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 looked for parameters with their unit defined as…
Tirdad Sadri Nejad
- 1,735
- 1
- 9
- 17
5
votes
2 answers
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 and improvements.
The section of interest for…
Buck8pe
- 1,674
- 18
- 44
3
votes
4 answers
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 non-inverting input, the common mode voltage…
floppy380
- 1,715
- 7
- 33
- 67
3
votes
0 answers
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 in using op-amp(741) as a comparator at high…
Bud
- 369
- 5
- 15
2
votes
3 answers
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 are fixed we can derive a transfer function…
user1245
- 3,955
- 4
- 37
- 87
2
votes
1 answer
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 should be double of Vos.
Please help me understand this…
Greenbanana
- 21
- 1
2
votes
1 answer
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 single +3.3 V supply (V+ = 3.3V, V- = 0V). The…
Bales
- 33
- 5
2
votes
5 answers
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 in gain.
After studying the art of electronics,…
Enrique Mendez
- 143
- 4
2
votes
3 answers
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 applied to force the opamp's output to zero…
user1245
- 3,955
- 4
- 37
- 87
1
vote
1 answer
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 bias current flowing through the 10 Ω resistor
produces…
Ronnie
- 310
- 2
- 10
1
vote
5 answers
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 and determine, under these conditions, the total…
Aleat
- 155
- 7
1
vote
0 answers
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 convergence problems for some edge cases, and I…
tobalt
- 18,646
- 16
- 73
1
vote
2 answers
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 above plot, it means the DAC output will be in…
ty_1917
- 949
- 1
- 5
- 20
1
vote
7 answers
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 something?
OP27 link.
Just to emphasize the importance of…
Antonio51
- 11,004
- 1
- 7
- 20