Questions tagged [single-supply-op-amp]
For questions about op amps that are marketed as capable of "single supply" operation. While all op amps can be operated with a single supply, op amps that are marketed as capable of "single supply" operation typically include an input common mode range and output voltage swing down to the negative supply voltage. Always use with the "operational-amplifier" tag.
204
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Single-supply non-inverting op-amp for summing DC voltages at unity gain
Is it possible to use this single supply, non-inverting, summing op-amp configuration to sum multiple arbitrary DC voltages at unity gain?
I've used the inverting summing op-amp config on bipolar ...
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-1
votes
1
answer
71
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Op-amp level shifter to shift 0.33-3.3 V to 0-10 V
I have an input signal ranging from 0.326 V to 3.3 V and I need to amplify and shift it so that the output will swing between 0-10 V. How can I achieve that using an op-amp? I know I could do that ...
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2
votes
2
answers
102
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When is the DC gain error of a single supply op-amp zero?
Suppose I designed a single supply op-amp, with \$V_{dd} = 1.8\mathrm{~V}\$, and \$V_{ss} = 0\mathrm{~V}\$. Furthermore, I designed the op-amp such that \$V_{out,max} = 1.3\mathrm{~V}\$ and \$V_{out,...
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2
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3
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82
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Input common-mode offset voltage ranges of op-amp
I'm using an MCP6V81 op-amp.
While trying to understand, I see that the output of the op-amp can't be greater than Vdd and less than Vss. If that's the case, could someone clarify how the common-mode ...
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4
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5
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Opamp with unbalanced rails
I'm using this - opamp.
I'm powering the MCP6V81 off +0.5V and -5.0V supplies. So the supplies are very unbalanced. Will this cause us any issues? Such as output offset, and drift?
Also, in the ...
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0
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100
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Narrow band band-pass filter design with LM358 op-amp
I am trying to design a narrowband band-pass filter with an LM358 op-amp, single supply 0-5 V. My requirement is a gain of 30 dB at center frequency 4 kHz and 20 dB attenuation at 3 kHz and 5 kHz.
I ...
-2
votes
1
answer
102
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Can't get op-amp to work [closed]
I'm working on a project where I want to amplify a small voltage from a DC motor to around 1-2 V using an LM358. I'm using a battery to supply Vcc and I don't need it to be able to output negative ...
0
votes
0
answers
65
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Need help with op-amp comparator circuit
I have two op-amps connected in series:
The first op-amp only acts as a voltage follower. It is connected to the voltage divider resistors and outputs V/2.
The second op-amp is acting as an inverting ...
-1
votes
3
answers
76
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Why do the following two ways of measuring op-amp DC offset show different results? [closed]
I tried following two configurations for measuring op-amp offset, which should give the same results by theoretical definition of offset where it is modelled as a voltage source at one of the input ...
11
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6
answers
517
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Need clarification regarding op-amp's ground/ reference and common mode dependence on supply
I am confused about several aspects pertaining to op-amp DC biasing and its effects on ground/common mode limits. The more I read about this, the more muddled up I get. I will try to frame my queries ...
1
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3
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144
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Why doesn't this op-amp schematic work?
If I use just the first-stage op-amp it works, but the output from the first stage is 2.5 V. If I give it some signal the output will be 2-3 V. In the second stage I use a voltage divider and the ...
3
votes
2
answers
565
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Single supply op-amp
In this example,
there is a "A TLV2461 operational amplifier IC is connected to provide a virtual ground for proper operation of the TLC074 from a single supply voltage."
I don´t quite ...
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0
votes
1
answer
101
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Why is my audio amplifier oscillating?
I'm trying to make a small audio amplifier using a TDA2822 stereo amplifier. It is working as expected, but it has some noise that will make you not hear the audio when I increase the volume on my ...
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0
votes
1
answer
54
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Bluetooth audio amplification
I made a circuit that consists of an operational amplifier and some capacitors and transistors so I can amplify the coming signal from any voice. Now I want to make this signal come from a Bluetooth ...
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1
vote
1
answer
98
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LM13700 does not completely reduce the sound
I have a problem with LM13700 - it does not completely reduce the sound when the control current is zero. For testing, I put together the most basic circuit, where the control pin is connected to the ...
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15
votes
2
answers
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What is causing the distortion in the negative cycle of this push-pull speaker driver?
I'm trying to build a unity-gain push-pull output stage to drive a small ~8 Ω speaker (measured DC resistance is 7 Ω; I don't have a datasheet for it).
This is for use with a single rail battery ...
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0
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0
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93
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Voltage controlled amplifier with single supply
I'm trying to make a voltage controlled amplifier circuit to control the feedback level of a delay effect. My big problem is that the circuit must be powered by a single power supply. I seem to have ...
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4
votes
2
answers
562
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How to lower input resistance of buffer (unity-gain) op-amp?
A practical op-amp connected in a unity gain configuration will have a very high input resistance (mega-ohms or higher). How can I add an external resistor to modify the input resistance to the kilo-...
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1
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96
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Converting op-amp circuit into inverting op-amp, single supply?
I'm currently trying to build an inverting op-amp with single 12 V supply for audio applications.
The circuit below is the one that worked super well with 12-0-12 (had low noise and low distortion), ...
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votes
1
answer
47
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Op-amp clarification in table
I'm using this Op-amp with Vcc of 5V and GND, voltage follower configuration.
Input to the non-inverting terminal is 0-2V (from a DAC). Output pin is connected to the inverting terminal.
Since, it's a ...
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1
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Does an op-amp's input-referred noise increase or decrease with decreasing supply voltage?
I plan to use the OP97F in an application using a single 5V supply, but all of its parameters are listed for +/-15V supply. There's a noise density graph showing it's valid from +/-2V to +/-15V but I'...
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OPA452 op-amp output voltage problem
I have a question about an OPA452 op-amp IC.
I am using the op-amp as a single supply amplifier.
My gain is 8, and V+ is 40V and load is 1k resistive to ground.
If the input voltage is 1V I measure ...
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0
votes
2
answers
223
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Need help to understand op-amp input resistor and capacitor network
I'm trying to understand the circuit design from this application note.
Here is the figure:
The author said:
Resistor RIN provides a dc return path for the VS/2 reference voltage and sets the ...
1
vote
1
answer
153
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Single transistor VCA for gate type CV signals
I am in the process of designing a sort of mini synth / noise machine and I'm struggling with the output stage. I only want sound to come out when I press the button, so based on some designs I have ...
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votes
2
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139
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Op-amp with both inputs the same doesn't output zero [closed]
In the picture below:
We have exactly the same input at both + and - pins of the op-amp's input (in the above picture, In1 and In2 are identical).
Normally we must have a zero output all the time but ...
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-1
votes
2
answers
111
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Simulating ground cancelling output stage in LTspice [closed]
I've tried to simulate ground cancelling mentioned by Douglas here:
The simulation cannot cancel ground noise:
V3 is noise pollution, V2 is microphone signal generator, V1 main power.
R8,R10,R9,C1 ...
- 552
4
votes
3
answers
791
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TL072P Opamp behaviour
After noticing a strange behaviour from a TL072P Opamp in a circuit I was building, I decided to test my stock, coming from two different batches, side to side.
I am getting confusing results when ...
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0
votes
2
answers
179
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Photodiode amplification circuit
I'm going to build photodiode amplification circuit which is then connected to ADS1115 controlled by Raspberry Pi, it has sampling 3.3k. The operational amplifier I ...
2
votes
5
answers
574
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High precision resistance meter
I'm designing a high precision resistance meter, which will measure the change of resistance of a given remote resistor, which is not placed on the circuit PCB, against temperature.
I want to do this ...
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votes
2
answers
110
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Why this ZCD not working?
I have a simple drawing of ZCD by using potential divider to stepdown the voltage feeding to the inverting and non-inverting input of LM358N.
The simulation result as below
In practical, I connect ...
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votes
1
answer
66
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Power/Sense line connections when a relay in path
I need to connect a power supply instrument with (power and sense line) to my IC; this IC is separated by a relay.
Can I connect/tie the sense line of the instrument close to IC in the layout (as ...
1
vote
2
answers
165
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Supply voltage for opamp in a current sink circuit
I want to use an opamp in a current sink configuration in order to control the emitter-base current of a PNP transistor via a digital-analog pin from a microcontroller.
The circuit is as shown below.
...
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1
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66
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Amplifying a pyranometer's small output using a single-supply amplifier
I am making use of theApogee SP-110-SS Pyranometer which outputs 0.2 mV per Wm-2. This pyranometer gives its true output over two cables, described as a positive and a negative output, where the mV ...
0
votes
2
answers
281
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Band pass filter with single-supply op-amp not filtering
I am working on a university project that requires me to build a 40kHz band pass filter for receiving an ultrasonic signal.
The filter is to be implemented into a portable device powered by a 9V PP3 ...
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4
votes
1
answer
484
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Op-Amp Voltage Follower not working at "extreme" voltages
I was testing the AD712 on LTSpice with a simple voltage follower.
In a perfect world, I'd get this.
Instead, I'm getting this.
Now, I am aware that op-amps do not reach their V+ and V- voltage and ...
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3
votes
1
answer
129
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Op-Amp inverter not working at high frequencies
I set up an inverting Op-Amp with the following schematic, inputting a 32.8 kHz signal. Two identical resistors on each side of the inverting input. Bias voltage is 7.5 V, Supply voltage is 15 V and 0 ...
- 707
1
vote
1
answer
129
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Ngspice convergence problem AD8606 simple simulation
I am new to electrical circuit simulation and I would like to simulate the behaviour of the operational amplifier AD8606 in a simple follower configuration, facing different loads.
In order to do that ...
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3
votes
5
answers
445
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Measuring bidirectional voltage drop across current shunt on positive rail
I want to measure a voltage drop across a current sensing resistor (in both polarities) on rails up to 30V using an Arduino / AVR ADC with 1V1 reference.
For background, this is a part of a battery ...
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1
answer
109
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Are there any differences between an inverting opamp with gain X vs. a voltage divider with gain X followed by buffer?
I'm looking for the advantages/disadvantages of using one over the other, especially for low-noise applications where I'll be feeding the output into an ADC.
In terms of AC response, the BW looks the ...
- 149
1
vote
2
answers
197
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Voltage follower configuration
for the LM4952 chip (class AB amplifier), I wanted to add an NE5532 OA in voltage follower configuration at its input.
That to take care of whatever input source will be plugged into it. Is it a good ...
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1
vote
2
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213
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Using a voltage follower to stabilize the ground in a single supply op-amp circuit
I was building a distortion circuit using op-amps and had to figure out a way to power the op-amp using a single supply, in other words I wanted to obtain +half supply voltage and -half supply voltage ...
1
vote
1
answer
65
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Converting a range on high side to a range on low side for very precise voltage sensing in ultra low power application
I have an ultra low power design running on CR2032 where it is critical to monitor precisely the current usage and the primary cell voltage during dev.
So I added a second MCU dedicated to ...
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1
vote
2
answers
180
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SMPS Pre Regulator Minimum load
I am designing a 30 V 5 A lab bench power supply having SMPS as a pre-regulator for the linear stage which will keep the SMPS output always 4 V higher than the main output voltage. This means SMPS ...
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votes
2
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184
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I am planning to design comparator based on Opamp but I am not getting the exact pulse output in LTspice [closed]
I am trying to simulate this but I am not getting the exact "RECTANGULR" pulse output. Kindly help me to figure out where I am going wrong.
I am going to use this circuit as pulse generator ...
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votes
4
answers
315
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In this voltage follower circuit why isn't the output voltage equal to the input voltage?
The image below shows the circuit and the plot of vin/vout in function of time. The green curve is the voltage source that is connect to the non inverting input of the op amp (so the 10V) and the blue ...
- 763
2
votes
3
answers
157
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Single supply op-amp saturates every time
Given a reference voltage level, I need to pick the difference with respect to that reference, amplify it and then convert it to digital. (Yes, I want to measure small voltage drops between two lines)....
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2
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131
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How to pass from a double-supply filter circuit to a single supply filter circuit?
So here is the main circuit, it's a lowpass filter-4th order bessel, so 2 sallen-key low-pass circuits in cascade. I already have all the components and transfer functions figured out but i would like ...
- 763
0
votes
1
answer
328
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High-voltage current sensing with floating isolation amplifier
I need to sense 200 V (to GND) 0.5-20 mA DC with minimum component count. After a lot of searching I think an isolation amplifier followed by a post-amp would give the lowest component count.
An ...
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1
vote
2
answers
360
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Single-ended 3.3V guitar preamp circuit is clipping and offset
I'm designing an audio signal frontend to take an electric guitar analog output and deliver it to an ADC channel on a microcontroller. The µC/ADC are 3.3V devices (...
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2
votes
2
answers
206
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What is the relationship between power supply rating and audio amplifier power rating?
I use many different types of Class D amplifiers in my designs. I am aware that the rated audio (RMS) power (with typical 10% distortion) relates to a sine wave which is not typical of music and audio ...
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