Questions tagged [741-opamp]

For designs using the venerable LM741 opamp.

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Using ua741 with an Arduino to increase the voltage range of a photodiode

I am trying to follow the instructions on this site to boost the voltage range output by a BPW34 using a ua741 opamp. It isn't working. I believe my opamps are not broken as I have tested them ...
Peter's user avatar
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OpAmp Offset Null Pins in LTSpice

I'm simulating the following circuit, where the Op Amp is an LM741: The LM741 is an 8-pin device, and this design calls for using 7 of them. From the datasheet, here are the pin connections: I have ...
Dan's user avatar
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2 answers
279 views

Offset on op amp output

I am building an integrator circuit on a breadboard using an LM741 op-amp. Below is the circuit diagram: The input to the circuit is a 10 kHz signal with a peak to peak of 1 volt (with 0 offset). The ...
MattODwyer's user avatar
1 vote
1 answer
93 views

Why doesn't my current source simulation in LTspice work?

I am trying to simulate a voltage-controlled current source in LTspice using the feedback current of an OP-amp as the load current. My circuit is: As an output, I get something around I_L = 620pA. As ...
Arad's user avatar
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287 views

How do I measure the output impedance of an inverting op-amp built with the LM741?

I am trying to measure the output impedance of an inverting op-amp. I tried it by connecting a variable resistor to the output. My objective was to use that resistor and output impedance as a voltage ...
Isuru Bhathiya's user avatar
1 vote
1 answer
84 views

How does the thermistor activate/not activate a circuit?

I have this schematic which is temperature-dependent and would only make a sound once the heat detected is above the threshold of the NTC thermistor. Can I get some help with circuit analysis? How ...
geekyhez's user avatar
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2 answers
101 views

Op-amp high-pass filter and low open-loop gain at higher frequencies

How can a high-pass filter work when the open-loop gain of an op-amp completely attenuates from a certain frequency? I understand that the open-loop gain of an op-amp is what limits every closed-loop ...
Gabriel9721's user avatar
16 votes
6 answers
2k views

How to tell what configuration a transistor has in a complicated circuit

Apparently transistor Q15 in the following circuit is in common collector mode (well, actually it says it's an emitter follower but my understanding is that this is the same thing as common collector ...
Urthona26's user avatar
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1 answer
142 views

How can I add a negative voltage with a positive voltage?

I am trying to measure the output voltage of a full H-bridge. I will post an image of the circuit that I am going to use. The design of the H-bridge is a bit more complex in reality but it is only ...
WalterPH's user avatar
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144 views

HB100 Doppler sensor calculation

I have a question about the first circuit schematics. I calculated the second circuit's fcutLow and fcutHigh frequencies like this: f2CutHigh = 1/(2 * π * 1M * 100p) = 1.6 kHz f2CutLow = 1/(2 * π * ...
Grammerking's user avatar
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The amplified output of a haptic motor does not produce a sine wave

I generate a sine wave (100-500 Hz) and amplify it using an LM741 op-amp with a gain of 3. When I measure the output everything is fine; I see a pure sine wave of the same frequency as that of the ...
mangozu's user avatar
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2 answers
270 views

741 in non inverting - single +5V suppl;y?

I need to amplify a +1mV to +100mV input with a gain of 10. I was thinking of using a 741 with this circuit https://www.electronics-tutorials.ws/opamp/opamp_3.html The specs say it's dual supply, ...
KevInSol's user avatar
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What is the effect of V+ given from bottom in this multivibrator?

In the astable multi vibrator, the second figure has a V+ voltage given additionally. What is the output of that circuit digram compared to first figure?
O-Negative's user avatar
1 vote
3 answers
470 views

What are the activation functions that can be generated using op-amps and filters?

There are varies activation functions in neural networks such as reLU, sigmoid and etc. I figured out that reLU function can be generated using simple diode circuit. What are the other activation ...
O-Negative's user avatar
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61 views

How can I sense the output voltage of an H-bridge using a microcontroller?

I have developed a circuit to control a Peltier cell using a H-bridge controller with two PWM signals. The brain of the whole project is a PIC24F, the circuit works (in this project I usually change ...
WalterPH's user avatar
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2 answers
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Do two or more subcircuits connected together change behavior?

This circuit for example: This is an op-amp circuit. It contains several subcircuits. I want to know how I can analyze this circuit. I found that I need to break the circuit into subcircuits, but I ...
Heroz's user avatar
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Practical integrator using op-amp

I'm trying to simulate a practical integrator using NI Multisim 741 op-amp. But I dont quite understand a variation in my waveform. I'm applying a 1 kHz, 5 V sinusoidal signal as input to the op-amp. ...
Techie5879's user avatar
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76 views

Op-amp linear inverting circuit question

I'm trying to implement a linear inverting circuit using NI Multisim. I'm using a 1 Hz sine wave with a 1 V amplitude as input. According to my circuit, the gain should be: $$A_v = \frac{-R_2}{R_1}=-...
Techie5879's user avatar
-4 votes
3 answers
366 views

Cannot amplify DC voltage using op-amps

I am trying to amplify a DC voltage scaled from 5-10V to another DC voltage with maximum 12V. Why I am not using just a DC voltage with that value? Because the input DC is variable according to some ...
M-125's user avatar
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-2 votes
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How to amplify DC voltage using Op-Amp?

In some real-application, a certain module is used, and the output voltage from this module is from 5 to 10 v. The required voltage should be scaled to 10, i.e. the 10v yields a 12v, 5v yields a 6v, ...
M-125's user avatar
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180 views

Amplifying signal with op-amp 741 doesn't work

I have a 500 Hz sine wave with amplitude 1V, and I need to amplify this signal 3 times, i.e. the required amplitude is 3V. I tried to connect the circuit two times as shown below, using gain 3/1, ...
M-125's user avatar
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2 votes
3 answers
290 views

Simulated 741 op amp has unexpectedly small output swing

While trying to understand the internals of op amps, I tried to implement a 741 circuit from Wikipedia in LTspice like this: (hooked up as 4x non-inverting amplifier, 0 and 24V supplies, some light ...
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1 answer
389 views

Trying to get a negative voltage for an op-amp

I am trying to make a curcuit using an op-amp, but the op-amp needs a -Vs and +Vs voltage. I don't know how to get the -Vs voltage. I'm looking for a method to get a negative voltage so I can use it ...
MarCoPolo's user avatar
1 vote
3 answers
704 views

Differential amplifier using LM741

I am trying to build a differential amplifier using the lm741 op amp, and simulate it in LTSpice. The dynamic range of the output is too small (about 20mV), I use a rectangular wave (3.3V) and 1.8V DC ...
MoMoIsBack's user avatar
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1 answer
50 views

Magnitute and phase, operational amplifier

I was solving exercises related to operational amplifiers and I got to a part where I am not sure how I am getting the arg part of the result. Can someone please explain this to me. Thank you very ...
mkdavor's user avatar
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1 answer
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Why would a 741 op-amp circuit saturate, and can it be fixed?

Some background: I teach circuits labs at a university and we use the 741 op-amp chip. I am aware that these chips are horrendously obsolete, but they are what we use. We specifically use the LM741 ...
Michael Stachowsky's user avatar
2 votes
1 answer
495 views

Why is CMRR defined differently in open loop and closed loop configuration of opamp?

I have recently been studying "Linear Integrated Circuits" and I am currently studying about opamp circuits. The books I am referring are Microelectronic Circuits (Seventh Edition) by Sedra ...
Anubhav's user avatar
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2 answers
560 views

What do the PNP transistors in a 741 differential pair do?

I am working on a project using the internal circuitry of LM741 op-amp and I've found its differential pair quite interesting. Mostly its NPN to PNP input. I've searched it to see what it does but ...
PowerTb321's user avatar
2 votes
3 answers
242 views

Why is voltage across sampling capacitor going below 0V

I am trying to design a sample and hold circuit for a project, but I am not understanding some of the results for my current simulation. When my control signal (V1) is turned off, the voltage over the ...
uhhhhhhhelp's user avatar
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1 answer
291 views

Small output offset in square wave generator using LM741

I am building a square wave generator using LM741 just like in this Falstad simulation. My problem is that the output has a small offset and I don't understand where it comes from. When measuring ...
PowerTb321's user avatar
-1 votes
2 answers
844 views

How to improve slew rate of LM741?

I am trying to implement a square wave generator with a specific output frequencies (15 - 45 kHz) but I've encountered a problem, the 0.5 V/μs slew rate. From what I've researched the main component ...
PowerTb321's user avatar
1 vote
3 answers
347 views

Active high pass filter experiment result

The pictures above are the circuit model and plot. uA741 of Texas Instrument was used as an op-amp on the circuit. 1 Vrms was used as an input voltage so that the output can be the voltage gain. The ...
Bak Gwang jin's user avatar
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2 answers
370 views

How to limit the output voltage of an op-amp astable multivibrator

I'm trying to make a square wave generator with an adjustable range of output signal amplitude (between 0 and 5V) using an LM741 op-amp and the following circuit: The thing is, VOUT is limited by the ...
PowerTb321's user avatar
0 votes
2 answers
231 views

Closed Loop Gain with Phase Reversal in 741 Op-Amp

This is a typical example of negative feedback in an Op-Amp - For this case, the feedback of the output can be controlled using a resistor divider, and let's call the feedback fraction to be X. We ...
electrovolt's user avatar
-1 votes
1 answer
379 views

Qualitative explanation of the high open-loop gain of a 741 op-amp using its internal circuit characteristics

Here is the internal circuit of a 741 op-amp: Using small signal analysis, I can claim the open loop voltage gain to be the product of the current gain of the transistors in the Darlington pair(Q15, ...
electrovolt's user avatar
1 vote
1 answer
625 views

Absolute value single supply op amp circuit on TL072 or MC4558

I would like to obtain an absolute value of input signal with TL072 or MC4558 op amps (or other amp) with single supply. When I connect the circuit upper one follows the signal and adds noise and ...
Jomonger's user avatar
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1 answer
85 views

Is it possible to use single power supply for both op amp bias and powering the mic?

Question as in the title. Can Vcc from identical source be used both for the op amp bias and powering the mic?
MBH's user avatar
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3 answers
1k views

DAC: Converting a DAC output 0-3.3V to 0-5V. Is it possible when the power supply is 5V?

I would like to convert the DAC output of a microcontroller from 0-3.3V to 0-5V. I will use the MCP6002 (rail to rail.) I have a power supply with 5V output. Can I get exactly 5V on output (Vout) or ...
ΝΙΚΟΣ ΠΑΠΑΣΤΕΦΑΝΟΥ's user avatar
0 votes
3 answers
1k views

How are potentiometers connected in an amplifier gain circuit?

I am trying to understand the circuit below. Please look at the highlighted circle, Imagine that the potentiometer has 3 pins namely, A, B, and C. If A is connected to -ve inverting input of the op-...
GeekWithGlasses's user avatar
0 votes
3 answers
60 views

Op-Amp circuit output analysis trouble

What is the output voltage Vo of the OPAMP circuit given below? Attempt at solution: THE ANSWER IS GIVEN: 6V, but according to me as the positive terminal is grounded the negative terminal will be ...
PRITAM the cat of Newton's user avatar
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0 answers
465 views

Interesting driving circuit of a voice coil actuator

I have an interesting circuit to drive the voice coil stage of an old acoustic microscope. I am struggling to understand what the different functions of the opamps in this circuit are. The circuit ...
REMberry's user avatar
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1 answer
601 views

PSpice Simulation of a 741 Op-Amp BJT configuration not working?

I'm simulating the following circuit of the 741 operational amplifier with BJTs: I've configured my circuit to be a non-inverting fashion, so in theory the gain would be -Rf/Ri. However, no matter ...
Zashiony's user avatar
0 votes
1 answer
98 views

Using a UA741 IC as sensor for an existing AA LED

I am trying to know if an air conditioning is ON/OFF (Daikin with only Wired Remote Control). I want to read its LED. The circuit is fed by a simple 17.8 V two wires from the machine. I've read the ...
Juan Falgueras's user avatar
2 votes
1 answer
989 views

Non-inverting UA741 opamp simulation on QUCS

According with instructions provided here https://www.youtube.com/watch?v=dBY1k5qK2w4 (in Spanish), I tried to simulate an inverting opamp configuration, but I couldn't figure out the right vout ...
Stefano Fedele's user avatar
-1 votes
1 answer
599 views

Tinkercad: amplify TMP36 signal with an opamp problem

I want to amplify the TMP36 signal with a simple opamp, but the multimeter Vo shows no result. The same happens for other configuration. How do I fix it?
谢RenS's user avatar
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0 answers
44 views

when there are 2 opamps in a circuit working simultaneously how do we sketch transfer characteristics?

could you please help me finding transfer characteristic (v2/v1) of this circuit.
youthwing's user avatar
1 vote
2 answers
1k views

Audio equalizer circuit using multiple feedback bandpass filter for each frequency band

I have a project to design an audio equalizer circuit with the following specifications. Bass band, center frequency = 180 hz, quality factor =0.7, range of adjustable gain 0.4-8 Midrange band, ...
EE Padawan's user avatar
4 votes
2 answers
841 views

Why does the datasheet only has one input bias current value?

There should be two input bias currents, one flowing into or out of the inverting input and the other, the non-inverting input. Their difference is the input offset current. A typical datasheet only ...
KMC's user avatar
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0 votes
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486 views

Problem in controlling the device temperature using an op-amp

OBJECTIVE: I have a device to which voltage is applied and this voltage has to be controlled according to the temperature detected by the thermistor that is placed on the device. If the temperature of ...
lomesh pudipeddi's user avatar
2 votes
1 answer
245 views

Optical quadrature encoder goes out of sync at higher speeds

I'm trying to get a microcontroller (stm32) to read a quadrature encoder, but running into an issue when at higher speeds line 1 seemingly gets narrower pulses until it gets out of sync with line 2. ...
oleg's user avatar
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