Questions tagged [operational-amplifier]
Questions relating to the construction and applications of operational amplifiers, which are DC-coupled, high-gain electronic voltage amplifiers with a differential input and, usually, a single-ended output.
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op amp code I/P E/SL I/SL
I'm quite new in the field. I need to purchase an op amp chips MCP6004, but I found different version (seems not listed in datasheet)
enter link description here
MCP6004-I/P Microchip,, Op Amp, RRIO, ...
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Configurable Constant-Voltage / Constant-Current IO
I'm currently working on designing a datalogger/signal processor for a project that requires a bank of analog output pins able to be switched between either constant voltage (0-10v) or constant ...
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How can I implement current control for proportional valves?
I am currently working on operating a proportional valve for airflow, but I am facing some challenges. Initially, I attempted to control it using a DRV8871 motor driver with PWM frequencies of 500 Hz, ...
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How do you turn on an LED when the input voltage is less than 12V?
I am designing a device that will check whether a fuse box motherboard is outputting 12V or not. I first considered diodes as they each have a 2V drop so I had 6 in series and functioned well but ...
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What are the commercially available op-amp ICs in the Indian market for making a charge sense preamplifier for a gamma ray dosimeter? [closed]
I need to make a gamma ray dosimeter as part of my academic project. Most of the op amp ICs used in journals and articles aren't available in the Indian market. Please help me with the list of the op ...
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Output voltage offset in an op-amp
I am trying to solve section d in the following question by substituting a current source of -Ios/2 at the '+' and +Ios/2 at the '-', as the resistor(s) found in section c would nullify the output for ...
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Using an opamp, I want to double a DC input signal that varies from 230 mVDC to 2300 mVDC. I want to use a single supply voltage of +5 vDC
Source: Circuit Digest - Practical Example of Non-inverting Amplifier
I want an opamp to double an input signal that varies from 230 mVDC to 2300 mVDC. That is, with 230 mVDC in, I want an output ...
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Find resistors for an inverting op amp band pass filter
I'm trying to save a problem that shows the following band pass filter:
Note: the op amp doesn't need to be a TL081, it's an abstract, ideal op amp.
I need to find resistors \$R1\$ and \$R2\$ so that ...
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Circuit analysis / understanding the control board for a heater
A very old heater unit at work broke down so we replaced one of its ~50 controller boards. All the boards are the same.
Just for the sake of practise electronics, I asked if I could take the board ...
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Convert square wave to DC using opamps
For a project I need to convert a 0-24V 200Hz square wave to DC.
The DC is supposed to represent the duty cycle of the square wave signal.
From this website I drew inspiration.
I've made a 2nd order ...
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Resistor values for a voltage-controlled current source circuit
simulate this circuit – Schematic created using CircuitLab
During my bachelor thesis, I am learning IGBT gate driver circuits. I am struggling with understanding the following circuit. It is a ...
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Can opamp directly drive the MOSFETs?
There is a 12 V DC source. I am also generating a 10 V source from it. The output is connected to a battery. This is basically a battery charging and cutoff circuit. The charging part is working fine ...
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How do the input current bias and the driven ground circuits in OpenBCI Ganglion work?
I am trying to understand how the OpenBCI Ganglion board works, but I can't figure out how these two sub-circuits work. I'm sorry I'm not too familiar with op-amps.
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Transfer function for CMOS opamp design
I am currently working on my bachelor thesis about readout interface for resistive gas sensors. In the whole schematic a use an opamp which I am currently trying to design. At first, I want to have ...
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How to find the tolerance on the output of an op amp circuit?
I'm trying to determine the accuracy of the DC circuit below but I am unsure how to account for input bias currents, input offset voltages, open loop output impedance, input resistance and open/closed ...
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Multiple Resistors for Rf in Op-Amp
Is it allowable to combine the R6 and Rx resistors shown below? The resistors R6 and Rx are in series, and I need to calculate the gain. Given R6=2kOhm and Rx=2kOhm, then can Rf be taken as 4kOhm?
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I don't understand this temperature controller circuit's behaviour [duplicate]
I am trying to build a circuit to regulate temperature for a few microheaters. Here's the circuit I am using:
This is a constant temperature controller circuit often found in the research papers and ...
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Is it good to equalize input impedances in cascade active opamp filters?
In my design, I designed a first 2nd order high pass filter with a Sallen key cut-off frequency of 0.2Hz and an input impedance of 250kohm. Then, I designed a second-order Multiple-Feedback low pass ...
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Nanovolts to millivolts signal amplification [closed]
I need to amplify a weak signal (a few nanovolts) from solenoid to a few hundred millivolts. I am working on an energy harvesting device but I am unsure of the output since the DAQ (HP 34970 A) works ...
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Simulation isn't working for high voltage amplifier
Been trying to simulate on multisim a circuit I saw about high voltage amplifier:
Schematic source seems to be:
EDN Design Ideas, 2004 - page 123 of 155 (displayed page number 110)
High-voltage ...
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OP Amp Circuit works with bench PSU but not laptop
I have a CMOY op-amp headphone amp I've cobbled to together mainly from the design here:
https://tangentsoft.com/audio/cmoy/misc/cmoy-tangent-sch.pdf
It works fine on my bench PSU but switching to an ...
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what is the purpose of the additional resistors and capacitors in the reference design of the multiple feedback fully differential low pass filter?
What is the purpose of the additional resistors and capacitors added C14 R12 R14 R13 R15 C15 in the reference design of the .second order multiple feedback fully differential low pass filter?
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Temperature and Light-Based Fan and Light Control Circuit Design [closed]
I am currently working on a project that involves creating a circuit to intelligently control the speed of a room fan based on the temperature and the room and toggle the room light on/off in response ...
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Convert analog piezo "transition" to digital signal
I'm trying to get what amounts to a knock indication into a microcontroller input from a piezo sensor. It's looking fairly good now at the fifth iteration, and about ready to provide digital levels ...
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Getting a square wave as a output of op-amp
I have the following op-amp circuit and i am trying to find out what is the open loop gain.
In order to make this simulation properly, we need to make sure that the
DC operation of the amplifier is ...
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Do you know how to add VEE and VCC power teminals to op-amp in Cadence that will be fit for simulation?
This is the op amp that comes with Cadence. I need to add a capacitor to the \$V_{CC}\$ wire and ground the \$V_{EE}\$ wire. However, there is clearly not a VEE or VCC on this op amp. Also, I know ...
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Voltage Buffer Vs Impedance matching
I am designing an Amplifier circuit for the microphone. For this, I am using a buffer in between two stages for isolation and I am confused between 2 circuits. I know, in voltage buffer circuits, the ...
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Measuring accurate voltage across a shunt resistor for high frequency AC current sensing
I am trying to measure the voltage across the shunt resistor to then be able to measure the flowing current. The output voltage will then be fed to a microcontroller or other ICs for further analysis. ...
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Calculate Gain of TS922
Im trying to figure out the gain of this opamp inside a st board. Here is the schematic where this opamp is used.
As you can see, the closed loop opamp with feedback has a voltage divider on the ...
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Differential Amplifier with the same entrance in both inputs
So, I'm supposed to find an equation that relates the output and input of an OpAmp. For both zero and first order. The circuit is the one in the image, it should be easy, since it's a Differential ...
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Impedance matching: headphones out / hijacked op-amp pin -> guitar input
I have a Vox "amplug" pocket amp which has a female 1/4" mono input, it's supposed to be dangling directly from the guitar's output jack, and has 3.5mm TRS headphones out. I'd like to ...
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Simple inverting op amp not working
I'm trying to amplify an electret microphone signal with an inverting op amp (LM358). I don't have access to an oscilloscope at the moment but with a voltmeter I read around 12mV at V1 and around 12mV ...
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Why is the output of this LM324 op-amp circuit 0V? Orcad/pspice question
I'm trying to make a function generator using three op-amps, specifically the LM324. Right now I'm trying make the first square wave output using a DC input:
My OrCad simulation's output constant ...
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Is using a buffer before a non-inverting input redundant?
I came across a circuit in someone's paper and noticed he buffers the input signal and routes it to the non-inverting input of the opamp:
I thought this is redundant since non-inverting input has ...
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Conception of an inverting op-amp with a specific gain
Consider the following circuit:
Consider the input voltage is \$v_1 = 0.1 \sin(\omega t) \$ with maximal current \$ 5 \mu A \$. I am asked to manipulate the circuit such that the gain is of \$ A_v = -...
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Voltage follower op-amp logic
Given the following circuit:
I don't really understand it. The potential at the (+) input of op-amp is 0 thus no current is going through the \$R_s\$. So it's basically just \$v_1\$ existing there, ...
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How to design an I/V Converter for Arduino
I'm new to the world of electronics and could really use your expertise. I'm attempting to create an I/V converter for a NOSHOK series 653 pressure sensor, and you can find the datasheet at this link: ...
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Non inverting opamp with bias DC
I'm doing a lab work on a circuit that takes a square signal in the input and first amplify it, then shape it and the amplify it again. So the circuit is actually composed by: an amplifier (inverting),...
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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, ...
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Which op-amp should I use to measure voltage across a current sense resistor?
I want to implement current sensing functionality on an MCU (STM32F103 bluepill), but in order to read voltages across the shunts, I would need a differential amplifier to eliminate noise first before ...
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How to make an LED light when motor stops running?
How can I make the LED light when the motor stops running (aka the output from the op amp (pencil drawn) is low and so the transistor base input is low)?
In this configuration. My LED lights when the ...
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PSRR of a folded-cascode op amp varies a lot in corners
My design of fc op amp can't pass Monte Carlo (mc) analysis in Cadence Virtuoso because my PSRR varies significantly in corners. PSRR varies from 80dB to 120dB in corners, where temperature changes ...
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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 ...
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Noise in high frequency photodiode op-amplifier
I am trying to use an op amplifier for my photodiode using this scheme:
The expected amplification is 5, ut instead I am getting a nearly constant output independent of light on photodiode.
I tried ...
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Determining Open Loop Gain of an opamp in LTspice
I'm trying to extract two characteristics: "Input Offset Voltage" and "Open Loop Gain" of an opamp LM741 by using LTspice.
To do that, I use the following circuit model and plots where the horizontal ...
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What is the purpose of these capacitors connected directly to the OpAmp output?
I am studying this schematic and I come across the following section:
As can shown capacitors are connected directly between the Op-Amp output to the supply (5V). What is the purpose of these ...
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LED "optical noise" when powered by DC
I am currently designing a circuit where:
An LED driven by a constant current driver shines directly into a photodiode. (I have also tried without the op amp constant current circuit.)
The photodiode ...
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How does the transistor in an op-amp log amplifier work?
In the figure, you could connect the transistor Q1 as a diode by shorting its collector with its base, but instead it is done by keeping both base and collector at ground.
The text says that if it ...
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How does Vout (DC) track VX (DC)?
I examined the both Vx and Vout with the Aspect Ratio in all transistors. I found that both are equal and I don't understand how this happens.
Could someone please explain with details, because I want ...
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How to generate a clock signal using an op-amp
I am trying to build a circuit which toggles a lamp on and off. I am using a JK flip-flop for the toggling action.
I want a clock pulse of 1 Hz. I know there are many ways to generate a clock pulse, ...
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