Questions tagged [dc-offset]
The dc-offset tag has no summary.
149 questions
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DC offset on power amplifiers output
I have a couple of questions about the DC offset on the output of the power amplifier. Lately, I've been trying a couple of designs in LtSpice and I noticed that DC offset is much too high(or so I ...
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1
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Why is there a random Input-offset error on my ADC that changes when I touch it and remove capacitors?
I have a hardware offset voltage at the input of my AMC131M01DFMR when HV+ and HV- are shorted. I would like to know how I can model it because it’s being quite erratic.
The circuit is relatively ...
- 47
2
votes
2
answers
157
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Triangle wave signal variable offset setting
So I have a triangle wave generator circuit for my VCO sweeping application. It works just fine but I want to offset the signal by +3.5V. I have tried DC biasing (Adding +3.5V to the triangle wave ...
- 55
2
votes
3
answers
120
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Amplifying and Offsetting a 2 MHz signal with a differential amplifier
I am building a ultrasound sensor system. I managed to work everything with development boards etc. Now I designed and manufactured my power board to power the system from a single source which ...
3
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4
answers
352
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How to derive the output voltage expression for an op-amp circuit with a DC offset at the non-inverting input?
I'm analyzing the following op-amp circuit:
A sinusoidal voltage source connected through resistor \$R_1\$ to the
inverting input.
A feedback resistor \$R_f\$ from the output to the inverting input.
A ...
- 43
1
vote
1
answer
100
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Offsetting a 2MHz signal before or after an opamp
I have a transducer excitation and echo signal that I wish to amplify and offset. The signals are around 2MHz, around -+2V and -+200mV. What I want to do is I want to amplify these signals and clip ...
0
votes
0
answers
94
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Designing circuit for clamping low voltage audio signal and then removing the DC for input through PC mic
I'm working on analog sensing circuit that will be connected to PC or other device through 3.5mm headphone jack. I started with simple android "loopback dongle" as described here. but ...
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5
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1
answer
318
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ADC Circuit Offset from Voltage Divider & Op-Amp
All,
I am using the ADS8664 and I am measuring a signal coming from a voltage divider. The input signal is essentially a DC signal, it changes but at a very slow frequency. The general schematic is ...
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1
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75
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What is \$V_{out}\$ for this input offset storage circuit?
in input offset storage, Page 5 from Dynamic Offset Cancellation Techniques
for Operational Amplifiers
When CK is high, \$S_1\$, \$S_2\$, \$S_3\$, \$S_4\$ are closed.
Voltage across the capacitors \$...
- 1,127
5
votes
4
answers
680
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Unexpected op-amp output waveform
I am building a sawtooth waveform generator based on the NE555:
In LTspice, I got a clear waveform:
In practice, the output signal has unexpected ripples like below:
What could be a reason for ...
- 63
0
votes
1
answer
61
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HCPL2531 offset voltage status at opto output
I am testing in a panel with very high motor noise. I want to pass the encoder data through the opto. When I apply the following scheme, my inputs and outputs are as I want.
Giriş
Çıkış
Then I ...
0
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1
answer
214
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Removing a DC offset with TL431
I have an electrical signal (output of ACS712), which is a sum of 2.5 constant voltage and an informative part, which is between 0 v and 0.25 v. I need to subtract 2.5 from said signal and decided to ...
0
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2
answers
268
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Removing DC offset from AD8220 output (Instrumentation Amplifier) in electromagnetic application
I'm using AD8220 to amplifying a very tiny signal, which is made by a electrode in a electromagnetic flow meter. In the voltage that is made by the electrode there is an DC offset, then this DC offset ...
- 1,438
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vote
2
answers
276
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DC offset on headphones output
I'm using this circuit as headphone output driver of a digital audio synthesizer that I'm building. The signal "DAC-OUT" is coming from the internal DAC of the microcontroller, and can reach ...
- 593
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1
answer
230
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DC Offset of a single-ended OTA
I'm confused by the concept of DC offset voltage. According to this application note by TI, DC offset seems to be the result of the asymmetry (Vth, bias current, etc.) - they only consider the '...
- 775
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1
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Offset of a comparator
I'm confused about the offset of the comparator. Consider a comparator consisting of a pre-amp and an inverter. Does the offset come from the misalignment of the preamplifier's Vocm and the threshold ...
- 775
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1
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240
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Negative offset voltage on analog input in data acquisition device (DAQ) connected to a photodiode in the dark
I have a data acquisition device (DAQ): USB-6002 from National Instruments (NI). I am recording an analog voltage from a (cathode-grounded) photodiode through a variable resistance (50-100k Ohms).
I ...
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2
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2
answers
291
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Excessive DC offset in high-speed opamp amplifier circuit
Background
A while ago I got my dad's old Musical Fidelity A1 MKI integrated amplifier from the early 80s (I believe). I found a blog that featured a lot of interesting information about this ...
1
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3
answers
183
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Level-Shifting not working in Instrumentation Amplifier
I want to shift the measured EMG input signal to the positive side to use ADC. I used the REF input of AD8421 to add an offset of 2.5V. I simulated the circuit below from the AD8421 datasheet on ...
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2
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174
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No DC offset observed in the CE amplifier circuit part
The objective is to make an audio amplifier. We have decided to make one that has four stages: a pre-amp with a gain of around 120, the next one is a CE amplifier with a gain of around 5, the third ...
1
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1
answer
216
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Square wave only has a positive side, how do we move it to the middle so it has a positive and negative cycle?
We have a project to make a function generator that outputs a square, triangle, and sine wave. We have already made one, but there are several problem with it.
The square output only has the positive ...
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1
vote
2
answers
259
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Removing DC in Analog Filter
Overview
I am working on an analog circuit that accepts input from four differential microphone inputs, amplifies, completes some basic filtering, and outputs a single rudimentary average of the ...
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0
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61
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DC Offset in LCD clock signal
I am getting DC offset in clock signal. Clock signal has 24MHz frequency. The DC offset is around 400mV. Also I was expecting Square shape waveform but I am getting sinusoidal with DC offset.
Clock is ...
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3
answers
1k
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Having trouble understanding op amp purpose
I came across an op amp circuit in a paper I am reading. The paper says it is supposed to be a 2.5 V dc offset, but I can't find a way to confirm that. I tried replicating it in LT Spice, but it doesn'...
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323
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How to add an offset to a PWM signal to control a N-channel MOSFET that has a large source voltage?
I want to control a N-channel MOSFET through a PWM signal generated by an Arduino board. The amplitude of such PWM is 0V-5V with respect to GND with frequency 20kHz.
My idea is to send the PWM signal ...
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3
votes
1
answer
267
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How do you compensate for a varying DC offset when using a wheatstone bridge?
Background
I have a sensitive magnetic sensor that is packaged as a wheatstone bridge with a 20k
device resistance. I am using it to measure the rotation of a magnet. It is possible to calibrate out ...
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2
answers
949
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Offset adjustment with unity-gain buffer
I want to include to my design an 'variable offset adjustment' circuit using an operational amplifier. This circuit would allow me to ajust the offset of my design. In my circuit, I already has a ...
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3
answers
1k
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DC offset correction loop. What's its advantage, compared to a high-pass RC filter?
Once in a while in literature I see DC offset correction loop.
What are the advantages of such DC offset removal loop, compared to an RC high-pass filter?
The RC filter would look like this.
I work ...
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458
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How to trim offset of a folded cascode op-amp when different voltage in applied to the input portion?
When the common mode input voltage is varied, offset is also varied. How can I trim them without using any pot?
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1
answer
1k
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Generate a sine wave with MCU
I want to generate a sine wave without an offset voltage. I generated a sine wave from 0 to 3.3 V and it has a 1.65 V offset. I need a sine wave from -1.65 V to 1.65 V using an MCU. How can I do that?
0
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1
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367
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DC offset cancellation
I am working on THz detector and was going through research papers.
In the receiver stage a preamplifier is used in the circuit shown below.
Why can't we directly use the amplifier?
How does the dummy ...
- 136
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161
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Is there a better way to digitally phase-control this triac?
This is a follow-up to a previous question which has a more detailed background of the problem I'm trying to solve.
I've built a wireless remote controller for a model train I have that runs on ~18VAC ...
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2
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1
answer
859
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How can I produce AC with a DC offset, isolated from my AC supply
I'm working on a project to provide remote control for model trains. The trains I am using are AC powered with approximately 0-20VAC applied to the rails. They have two features: directional control ...
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6
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2k
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How to offset a 15 VDC signal to be visible on the scale of 50 mV?
I'd like to watch the output from a power supply to evaluate noise and distortion. The output is 15 VDC.
Unfortunately, when I zoom in to 50 mV per division, the signal is off the scale. I'm using ...
- 1,463
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3
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How does this LLC converter keep 50% duty cycle and zero DC offset with AC-coupled feedback?
I'm currently designing an LLC resonant DC/DC converter with 12V input, +/-15V output and nominal 200W combined output power. I've already got my resonant circuit, transformer, gain curves and power ...
- 20.9k
9
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2
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576
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Unwanted DC offset at the input of inverting op-amp
I'm designing an envelope generator for a sort of mini synthesizer I'm currently working on. I want the envelope signal to evolve (rise or decay, depending on the SPDT switch) only when the switch (...
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1
answer
312
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How does the offset correction work in this circuit?
I'm reading a paper about a received signal strength indicator (RSSI) amplifier. The amplifier was to estimate the relative power of the input signal, and was designed by cascading 6 limiting ...
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3
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2k
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How is DC bias offset removed in a differential amplifier circuit?
Looking at the long-tailed pair, if we remove the dual supply and bias the amplifier for single supply operation it will generate a DC-shifted signal. How is this DC-offset typically cancelled for ...
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2
answers
3k
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DC offset of DC signal with op-amp
I have a DC signal from a DAC in the range of [0:3,3]V and want to convert it to be in the range [-5:5]V. My approach would be to scale with op-amp with gain 3 and then DC offset.
I've read that this ...
0
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1
answer
505
views
What could be the cause of a constant voltage offset on the STM32L041G6 ADC?
I have been testing the ADC on my STM32L0 with 12-bit resolution and for some reason, every measurement I take has a 0.048 V offset. I've tried a different supply voltage (from 1.8 V to 3.3 V), but ...
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What is the reference voltage of Vin- and Vin+ in this circuit?
I'm trying to make a PCB board to measure Electrocardiogram (ECG) signal. I have some doubts about the DC offset of the 2 input signals (\$V_{IN-}\$, \$V_{IN+}\$) with reference to analog ground. I ...
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Calculating offset voltage [closed]
This is a circuit that is in my textbook, the derivation for the offset voltage is not provided only the end result is. I would really appreciate it if someone could please help explain how this is ...
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3
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1k
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How do I calculate a voltage divider with an offset
I've got the following circuit:
simulate this circuit – Schematic created using CircuitLab
By running the simulation I can see that a signal voltage of 3.13 converts to an output of 2.14, but I'...
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1
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327
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DC offset and amplifier
I have a very small AC signal from a receiver coil of Metal Detector that I want to provide some DC offset so it can be handled by a microcontroller after it is amplified. I came up with this solution....
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2
answers
1k
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Removing DC offset in MATLAB
My teacher has a demodulated signal and he removed the DC offset with this one line of code in MATLAB:
y_dc = y - mean(y)
Can someone please explain how this line ...
user279216
1
vote
0
answers
246
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Measure dynamic comparator's offset voltage
I'm trying to characterize a comparator I built and I am wondering how I can plot offset voltage over time. I would like to eventually add a calibration block that will reduce the comparator offset ...
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1
answer
2k
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Confusion regarding term "offset"?
I am confused regarding term "offset".
What is its meaning in context of function generator and oscilloscope?
I have tried to google, but I get results in context of op amp and some results ...
- 1,181
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3
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838
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Why is it important to eliminate ground-shift at the ground of a microcontroller?
I've asked a question about differential amplifiers and their uses in measuring current through a shunt.
In doing so, lots of people advised me not to sense current on the low-side since that can ...
- 653
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1
answer
122
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How does this DC offset sinwave input work?
I have learned that this circuit will move the sin wave up to a DC points due to the voltage divider, that is:
V_out = V_in + Vcc*R2/(R1+R2)
I was using LTSpice to simulate this and it works, I try to ...
- 521
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3
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852
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Is using a passive RC high pass filter at the output of an opamp a good method to remove DC offset?
All the information I am able to find related to this discuss about AC coupling the inputs of an amplifier but never the output. I wish to know if there are any issues with AC coupling at the output. ...
