Arduino Stack Exchange
Arduino Stack Exchange

Questions tagged [op-amp]

An op-amp (operational amplifier) is a high gain analog voltage amplifier with differential high impedance inputs, and a low impedance output. A basic building block in signal processing, like as amplifier or active filter.

An opamp is a high gain amplifier, which amplifies the voltage difference between its two inputs.

An ideal opamp has the following properties:

  • infinite open-loop gain
  • infinite bandwidth
  • zero input current
  • zero output impedance
  • zero offset voltage

Real op-amps often have gains of minimum 100 dB, which makes them of little use without feedback. Negative feedback is most often used, and allows the design of inverting amplifiers, non-inverting amplifiers, integrators, differentiators and filters. Positive feedback is used to construct Schmitt-triggers.

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HX711 - Inconsistent Readings

simulate this circuit – Schematic created using CircuitLab Wiring is based on the scheme presented below - (Reference: https://electronics.stackexchange.com/a/174580) I am using Arduino Mega 2560, HX711 and four load cells to build a weighing…
PSharma
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Controlling op amps amplification ratio by arduino

Is there any option how to control amplification ratio of operational amplifier by some logic signal which can be produced by arduino? I am talking about some clasic op amp like lm356 or ui741 in basic inverting or non-inverting circuit (i would…
FoksaK
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I am facing a problem of firing multiple interrupts on nodemcu 1.0 on single rising edge pulse.what is problem and what are the solutions?

I am working on a project which involves counting the drops falling in a drip chamber of a IV fluid gravity based therapy bottle(saline bottle).I am using IR trans-receiver at the drip chamber to detect a drop falling. I am using a comparator to…
CHETAN NIRADWAR
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Amplify Piezo Sensor

I am trying to amplify a piezo sensor per the instructions found at the link below. I am not trying to trigger a buzzer only print to the serial monitor whether the vibration was detected or not. I am a NOOB with respect to circuits and unable to…
GBG
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How to offset PWM output so it would also have negative amplitude?

So PWM goes from 0 to 5V. How could I do -2.5 - 2.5V? Basically I am asking how to add offset to PWM signal. Should I use operational amplifier? How would I use it? I never had to deal with them, but I have LM2904P laying around.
Name
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Signal clipping in Arduino Serial Plotter

I would like to understand why did Arduino clipped the input signal as shown in the attached diagram? As far as I know, Arduinos are able to read analogue voltages up to 5v, that is 1023. But for some reason my signal got clipped at 390 which is…
Nawaz
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Mesure sensor voltage by 328p and OP Amp in parallel

I am designing a circuit to measure the temperature via a thermistor via the ADC pin on a 328p and I am looking for some advice. As a failover I am also using an OP Amp as a comparator, to see whether the voltage exceeds a certain threshold. My…
jack
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Reading ground signal from circuit

I am trying to detect whether a signal is high or low from an ESU LokSound 5 decoder for HO locomotives. My idea was to use one of the auxiliary pins used to drive an LED (AUX 3 in my case). The problem is that these decoders are common positive…
DuluthIsSuperior
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Arduino IDE on Attiny45: What kind of power does a chip need?

I have this little AtTiny45 which I'm loading a program with Arduino as ISP. My goal to use this chip along with a op amp, a piezo buzzer and a press button, and have it automatically sleep between uses. I intend to use 2 3V pill batteries in…
B7th
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Noise in Analog Read Serial from an instrumentation amplifier(ina122p)

I am trying to read the values from a simple EMG circuit (with an INA122P) using the analogRead() and plotting in the plotter using an Arduino nano v3. I am powering the ina1222p from the 5v pin of the Arduino. But no matter what I do, the signal…
Plutonian Fairy
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Amplification of microphone circuit

I am getting constant values and I need to know the amplification of the circuit. I believe that amplification = R8/R6 though I am not sure.
Diana Lc
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Arduino Uno - Analog Circuit Simulator

I control an analog circuit with Arduino Uno. I want to simulate an Arduino Uno with operational amplifiers (741). Can I simulate Arduino with SPICE?
Νίκος-Μάριος Κοκολάκης
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Stable amplitude of amplified signal

Is there any circuit with opamp where can be (by arduino) set constant output amplitude which doesn't depend on input signals amplitude?
FoksaK
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Does using multiple HX711 amplifiers change the supply voltage of an Arduino?

I’m creating essentially a load cell using an Arduino Nano and an HX711 amplifier. However, I want to have two HX711 amplifiers running off the same Arduino. Will that change the supply voltage since I’m using two (ex. Does it change from 5V to…
Suomynona
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op amp circuit single sourced from arduino power

Getting an audio signal from a 3.5mm jack amplified (non-inverted) and fed into analog in pin on a Mega 2560. I am having problems using a potentiometer as a variable resistor to adjust gain. I'm also getting a lot of noise (+/-10 units on the…
What The J
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