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Questions tagged [dc-offset]

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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 ...
Dimitri Petrucci's user avatar
0 votes
1 answer
35 views

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 '...
Jack Black's user avatar
0 votes
1 answer
36 views

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 ...
Jack Black's user avatar
1 vote
1 answer
63 views

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 ...
Omnistic's user avatar
2 votes
2 answers
121 views

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 ...
jonatan.wilund's user avatar
1 vote
3 answers
103 views

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 ...
Keestu's user avatar
  • 25
1 vote
2 answers
120 views

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 ...
JackSparrow9875's user avatar
1 vote
1 answer
141 views

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 ...
Beans Carlo's user avatar
1 vote
2 answers
138 views

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 ...
boltscorpion's user avatar
0 votes
0 answers
34 views

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 ...
Harish's user avatar
  • 1
3 votes
3 answers
1k views

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'...
user1402154's user avatar
0 votes
1 answer
167 views

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 ...
Barzi2001's user avatar
  • 113
1 vote
1 answer
114 views

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 ...
Nabil's user avatar
  • 111
0 votes
2 answers
418 views

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 ...
Developing Electronics's user avatar
7 votes
3 answers
916 views

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 ...
misk94555's user avatar
  • 392
1 vote
1 answer
280 views

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?
K. M. Sayem Bin Rahmotullah's user avatar
1 vote
1 answer
519 views

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?
Ali Buğra ÇETİN's user avatar
0 votes
1 answer
250 views

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 ...
prashanth's user avatar
  • 116
0 votes
0 answers
86 views

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 ...
zstewart's user avatar
  • 121
2 votes
1 answer
468 views

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 ...
zstewart's user avatar
  • 121
4 votes
6 answers
1k views

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 ...
Jerzy Przezdziecki's user avatar
4 votes
3 answers
614 views

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 ...
Jonathan S.'s user avatar
9 votes
2 answers
515 views

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 (...
Javier Soto's user avatar
3 votes
1 answer
190 views

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 ...
Jack Black's user avatar
0 votes
3 answers
983 views

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 ...
SubZero's user avatar
  • 338
3 votes
2 answers
2k views

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 ...
Ognyan Petkov's user avatar
0 votes
1 answer
347 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 ...
GbNusko's user avatar
  • 11
1 vote
1 answer
594 views

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 ...
Jack Black's user avatar
0 votes
2 answers
1k views

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 ...
harry's user avatar
  • 11
2 votes
3 answers
827 views

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'...
MikeSchem's user avatar
  • 153
0 votes
1 answer
265 views

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....
asim's user avatar
  • 600
2 votes
2 answers
958 views

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 ...
user avatar
1 vote
0 answers
163 views

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 ...
PrematureCorn's user avatar
0 votes
1 answer
935 views

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 ...
DSP_CS's user avatar
  • 1,227
0 votes
3 answers
579 views

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 ...
A.H.Z's user avatar
  • 633
2 votes
1 answer
100 views

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 ...
Dat's user avatar
  • 449
0 votes
3 answers
508 views

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. ...
needbrainscratched's user avatar
0 votes
0 answers
88 views

How to block DC offset voltage on a potentiostat output?

I have an AUTOLAB potentiostat: working electrode (WE, Pt wire), counter electrode (CE, Pt wire), reference electrode (RE, Ag/AgCl solid state). I would like to capacitively couple the potentiostat ...
Ryksa's user avatar
  • 13
3 votes
3 answers
2k views

How to implement gain and offset in a single opamp?

I tried designer here in this page. But my particular case (Case 2) seems not working in the page. Then I Read this document and my case there, is section 4. But my calculation results are not ...
UB_Roy's user avatar
  • 163
1 vote
1 answer
308 views

Remove DC comp offset of AC current

I am attempting to build a circuit that excites a sensor which requires an AC current of ±1mA and 20kHz frequency. For this, I used voltage to current converter integrated circuit XTR110, which is ...
Mr.Edel's user avatar
  • 11
1 vote
1 answer
198 views

Unkown DC offset of an isolation amplifier circuit design

I am designing an isolation amplifier that consists of the following blocks: A comparator which produces a PWM signal A coupling capacitor that achieves galvanic isolation A voltage follower that ...
Karol Warvic's user avatar
1 vote
3 answers
218 views

Low-frequency high.pass filter drifts with temperature

for a phase sensitive measurement, I would like to have the DC offset of a signal cancelled. The AC-signal will be amplified and then the phase of it is measured in reference to another AC-signal. My ...
T.K.'s user avatar
  • 11
4 votes
5 answers
2k views

Accurately amplifying a number of current sense transformers

I've got 16 current sense transformers that are being used to monitor AC loads. The SCTs are current output type, producing 50mA on a 100A load. The maximum burden resistance is 10Ω, thus the voltage ...
Polynomial's user avatar
  • 10.7k
1 vote
2 answers
145 views

What kind of op-amp circuit is this?

I am trying to understand the circuit have shown below. As far as I tried, it seems a differential amplifier for me. So, I tried to solve it in the way we deal with DC signals. But I failed to solve ...
CNA's user avatar
  • 675
3 votes
2 answers
143 views

Wheatstone bridge to create offset

While comparing schematics of two old analog oscilloscopes (Tektronix 475 and Goldstar 9020,) I was expecting many differences to get better frequency response since the first is a 250MHz and the ...
Paul Ghobril's user avatar
  • 2,906
3 votes
0 answers
165 views

Sawtooth VCO DC offset issues

[Apologies in advance for possible misuse of terminology. I don't have any formal education in EE and am mostly self taught, so I may be lacking in some fundamentals.] I am trying to design a discrete ...
wurly's user avatar
  • 31
0 votes
0 answers
75 views

What is the practical difference in this DC offset remover?

I am working on audio signal oscillators. My oscillator generates 0V to +5V triangle wave. Then I'm removing DC bias to get -5V to +5V signal. I have found two examples on how to do this: What is the ...
somerandomusername's user avatar
1 vote
1 answer
97 views

high voltage DC biasing on top of low voltage AC with floating load

I am in process of designing a power supply for heating a filament in an electron gun. The AC heating current has to float on top of DC high voltage acceleration voltage. The following circuit seems ...
Don I's user avatar
  • 13
1 vote
2 answers
1k views

Meanwell Led driver: internal 3-in-1 dimming circuit

In Meanwell led drivers like the ones from the XLM, HLG or LCM families, how does the internal circuitry for the 3-in-1 dimming feature (0-10V, 10V PWM, 0-100kOhm) look like? I use a LCM-25 in my ...
Sim Son's user avatar
  • 2,793
0 votes
1 answer
351 views

ua741 DC offset on the output

I have ua741cn and connected it to 10V. V_+ =10V V_- =GND Just to verify I have a valid chip I did a little test. I connected the non-inverting input to GND and the inverting to 10V I would expect the ...
DDonkey's user avatar
  • 83