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.
230
questions
4
votes
4
answers
249
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Single supply positive-only signal amplification using INA126 (two op-amp in-amp)
I need to amplify a 0.15-0.8 V very low frequency signal to the 0-10 V range of an ADC. I'm having a hard time figuring out why an INA126 does work as expected with dual supply but seems not to work ...
2
votes
1
answer
107
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Apparent contradiction in op-amp datasheet
I'm building a high-voltage regulator whose error amplifier is an op-amp.
I'm relatively new to op-amps and currently using cheap single-supply LM324 so mistakes don't cost much. The error amplifier ...
1
vote
1
answer
83
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Oscillation when oscilloscope is attached to op-amp output
I have a simple op-amp circuit (LT6200) designed to amplify a narrow-band signal centered around 1 MHz. The schematics is shown below.
And below is the simulation in LTSpice
I have two problems:
...
2
votes
0
answers
78
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Advice on active line-level audio mixer using a single supply rail
A few years ago a asked a question about an active audio (line level) mixer I wanted to make. I got some advice about how to run it off a single supply to make things easier and I was hoping to come ...
1
vote
0
answers
37
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How to determine gain of this op-amp setup
This circuitry is present to form current signal (from current transducer - LEM) to voltage signal (to be feed to the ACD).
It doesn't represent typical setup of non-inverting opamp (lack of the ...
1
vote
3
answers
248
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LED in op-amp`s feedback loop shines dimly. How to eliminate this?
I am working on my project's visual indicator part.
Everything woks as expected, but LED shines dimly when connected in feedback loop and with no control signal. Shining is barely visible, but it is ...
3
votes
5
answers
584
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LM358 output problem
I have a problem when using LM358 in compare mode.
I'm trying supply LM358 with 5V (V+ = 5V, V- = GND).
The non-inverting input is 0.6V and the inverting input is 0V and 1.2V, respectively. When the ...
0
votes
3
answers
331
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How to isolate audio signals from each other using op-amps with the same single supply?
Reuploaded corrected picture, as the old one was with confusing ground connections:
I am new here, so please be patient if I'm doing something wrong. I really need some help as I can't figure it out ...
0
votes
3
answers
67
views
2nd-order Sallen-key low pass filter with unity gain outputs rail voltage when input is 0V
I was designing an active low pass filter for simple sigma-delta modulation signals. I found that the op-amp will output 3V when the input is 0V given that the power supply is 0~3.3V.
I simulate the ...
0
votes
1
answer
138
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Op-amp schematic connection questions and DC biasing
In the first stage the signal is converted to single-ended, and it is amplified using a digital potentiometer in the second stage to be able to change the gain with a microcontroller.
In the last ...
1
vote
2
answers
211
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I would like to know what type of op-amp this circuit is
This circuit is connected to 250V AC power and I would like to calculate the values of the resistor and capacitor, but I don't know which formula to use to calculate it.
I think this circuit is ...
8
votes
4
answers
1k
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Hysteresis on inverting terminal for comparator circuits?
If you examine 98% of circuits online that include hysteresis for a comparator, they always implement the hysteresis on the non-inverting input, like so:
This is easy enough to calculate. However, ...
2
votes
1
answer
164
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Noninverting input voltage seen on V+ pin of OpAmp
I've built this exact circuit here, except for one variation: SHDN is connected via a 10K resistor to ground. The opamp should be off!!!
What happens is when I connect a battery (or power supply) to ...
0
votes
1
answer
36
views
Unity gain circuit with LF353 is creating gain over 1 for low signals
I have larger curciut with a small stage for signal decoupling and stabilization using a unity gain amplifier based on an LF353. I don't have any real requirements for speed. My signal input is quite ...
2
votes
1
answer
110
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LM358 Output Voltage Issue / Compensation
I am working on a PCB to take a 0-5 VDC signal and convert into a 1-5 V signal with two channels and two op-amps. This is done with a voltage divider that takes the 5 V signal and converts to 0.995 V, ...
0
votes
1
answer
111
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Single source, single-ended to differential output low pass filter
I want to design an IEPE sensor signal conditioner. This signal conditioner that I will design will not include gain and attenuator parts. The signal from the IEPE sensor will pass through the ...
2
votes
1
answer
62
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How to smooth DC output from an op-amp precision full wave rectifier?
I am using the circuit below to rectify the AC voltage from a current sensing transformer. It is a single supply full wave rectifier, which I intend to use to measure this voltage with a ...
0
votes
1
answer
88
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Non-constant active filter gain
I designed an amplifier using an instrumentation amplifier and an operational amplifier. Here, I used a 2 Hz high pass and 100 Hz multi feedback low pass filter, but I could not get the efficiency I ...
1
vote
1
answer
83
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ad8426 instrumental amplifier design
I'm having a problem with my AD8426 instrumental amplifier design. As I show in the image, I use a 3.3 V supply and after increasing my input signal, I use 1.8V virtual ground to make it oscillate on ...
6
votes
2
answers
303
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Single-Supply OpAmp design
I am trying to come up with an amplifier that can amplify an input audio signal about 4-5 times. This is my first time designing an amplifier, so please bear with me.
The circuit must operate on a ...
0
votes
0
answers
49
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Analog isolator to Differential Amp to Differential ADC
I'm using an ADC from Linear Technology, LTC2344-16 , and i have to measure an isolated voltage through an analog isolator TLP7820 and a FDA,like in figure below:
I draw the schematic with the goal ...
2
votes
1
answer
297
views
Understanding powering op-amps
I am working with an op-amp LM741. I'm not using it for audio applications, just simple DC voltage stuff for educational purposes. As long as the output is ultimately a positive voltage (think non-...
2
votes
1
answer
152
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Output voltage drop LM358
I am running a LM358 in a simple non-inverting amplification circuit. I am using the single rail supply option, grounding V- and applying 24V to V+. The input voltage is 4V and I want to amplify it as ...
-1
votes
2
answers
123
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Understanding and specifying op-amp and transistor spec to deliver maximum current from input to output
I have the circuit below working in LT Spice and on a breadboard. It appears to be working as expected - but I'm now at my theoretical limits so I need some help developing and testing it from here 1.
...
0
votes
2
answers
72
views
Pressure sensor output not clear from datasheet
Planning to use the following sensor:
https://shop.bb-sensors.com/Druck/Drucksensoren/
Part number SHOP 0391 0004-02M.
I am planning to give 3.3 VDC to sensor. Pressure input will be 0 to 10 bar. It ...
2
votes
3
answers
376
views
Should op amp reference terminal be connected to ground?
I would like to amplify the voltage from my thermocouple and had a couple of INA122s on hand. This is from the datasheet.
Should pin 5 be connected to GND? (pin 4)
5
votes
5
answers
1k
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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 ...
-1
votes
1
answer
210
views
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 ...
2
votes
2
answers
264
views
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,...
2
votes
3
answers
300
views
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 ...
4
votes
5
answers
1k
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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 ...
0
votes
0
answers
385
views
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
104
views
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
87
views
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
109
views
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
votes
6
answers
943
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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
vote
3
answers
167
views
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
724
views
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 ...
0
votes
1
answer
140
views
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 ...
0
votes
1
answer
71
views
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 ...
1
vote
1
answer
193
views
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 ...
15
votes
2
answers
1k
views
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 ...
0
votes
0
answers
222
views
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 ...
4
votes
2
answers
735
views
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-...
0
votes
1
answer
148
views
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), ...
0
votes
1
answer
51
views
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 ...
0
votes
1
answer
74
views
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'...
1
vote
1
answer
79
views
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 ...
0
votes
2
answers
470
views
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
347
views
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 ...