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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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Level shifting 0-5V signal to +-2.5V Signal

Part of the data sheet of the ANS1115: Hey guys, I am new to electronics and hope that you could help me. I got a 49E linear hall effect sensor (data sheet) which outputs a 0-5V signal. I am feeding ...
Daniel's user avatar
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1 vote
4 answers
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Trying to Build Basic IEPE Circuit: Facing issue with the Op-amp

I am building a simple IEPE Circuit for this IEPE Microphone but I am facing issues with the Op-amp. I have connected the signal output from 22uF capacitor to non-inverting configurated Op- amp ...
Brendan D'souza's user avatar
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2 answers
108 views

Op amp Inverter Amplifier

In the following circuits, ideal op-amps are used: Circuit 1 - The non-inverting input is grounded through a 2 kilo ohm resistor. Circuit 2 - The non-inverting input is grounded directly. Are the ...
madhuranga ishaka's user avatar
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1 answer
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I want to know R2 value wrt Vin and Vout of HCNR201 circuit

I'm trying to learn this circuit, it is HCNR201 (Source - HCNR201 High Bandwidth Evaluation Board User Guide). I want to calculate value of R2 w.r.t. Vin, Vout and HCNR supply. Specially trying to get ...
Bhushan Waghe's user avatar
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2 answers
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Differential line driver built with discrete components

I need to establish an SPI communication over one meter in a very noisy environment. To do this, I am planning on using differential communication over a twisted pair cable. I would use a dedicated IC ...
zeeman_effect's user avatar
1 vote
1 answer
275 views

Why I can't get required OpAmp gain?

I have this basic non-inverting opamp. Input is 20Vpp with required output of 101.8Vpp. LTC6090 seems to fit the bill. However, to get gain of 5.09, LTSpice simulation shows output is clipping and is ...
Ariel Narboada's user avatar
3 votes
3 answers
274 views

Increasing current biases of multistage amplifiers

I remember my professor talking about op amp and he said when we have a multistage amplifier (for instance an op amp) bias current for second stage of amplification must be more than the first stage ...
amin mokarami's user avatar
-1 votes
1 answer
31 views

Sensitive Transimpedance Amplifier frequency bandwidth [closed]

I've built the transimpedance amplifier based on this project Sensitive Transimpedance Amplifier Oscillates. I've used op amp LMC6001, symmetrically power 5 volts, feedback resistor Rf = 100MΩ, ...
Paweł Chmolewski's user avatar
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0 answers
35 views

STM32L432KC used for negative voltage?

My TIA circuit's opamp needs a negative supply in order to get a output with a 2V dc bias and ac signal that the stm adc can sample. This is needed since the opamp needs a ~3V difference between input ...
Visje999's user avatar
2 votes
4 answers
168 views

Is there current from Vin in this ideal op-amp circuit?

Before we start: yes, I already know the there is no current flowing into the inverting or non-inverting terminals of an ideal op-amp, and that the node between R1 and R3 is 0 V. The Question: ...
MikeWazowski's user avatar
1 vote
1 answer
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Placing the feedback components close to the inverting input pin or output pin?

In closed-loop operation amplifiers design, should we place the feedback components close to the inverting input pin or output pin in our layout? and why? For example for this design: I put the ...
Andromeda's user avatar
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Why can't this op-amp circuit output 0V with a single power supply?

I have this basic design. The input is from a signal generator (rectangular pulses 0V-6V 10Hz.) The desired output is 12V pulse 10Hz. I would like to avoid using -15VDC supply but with a single ...
Ariel Narboada's user avatar
3 votes
1 answer
118 views

Negative feedback circuit (op-amp)

This is kind of school works. I have to calculate a voltage gain of the circuit below. Prof told me that the circuit can be simplified as a op-amp circuit which has negative feedback. To obtain the ...
abeloejmn's user avatar
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1 answer
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How do I read amplified voltage using an Arduino UNO

...
Official Pyramid's user avatar
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2 answers
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Best way to generate a variable clean DC current

On one end I have an amArduino or other microcontroller. On the other end I have a small electromagnet coil with about 20 turns of 1 inch diameter. I need to drive this coil with some precision (say 5-...
user1402154's user avatar
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23 views

Does a buck-boost converter serve as enough circuit protection for an automotive application? [duplicate]

I am designing a circuit for a automotive application which is meant to map voltage ranges between two airflow sensors (i.e. 1 sensor has an output range of 1.75-7.0V and I want to replace it with a ...
Jayson Okhman's user avatar
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1 answer
42 views

Micro switch capacitance on the inverting input pin of operational amplifier

I want to use a microswitch on the inverting pin of my transimpedance amplifier to be able to select two different channel of my transducer as follow: It the microswitch datasheet in is mentioned ...
Andromeda's user avatar
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Operation amplifier optimized layout- Noise- Signal Integrity

I was watching a seminar from Fedevel academy, in this seminar as all the datasheet has mentioned, we need to remove GND and PWR plane underneath the negative inverting pin and the output pin of the ...
Andromeda's user avatar
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0 votes
4 answers
101 views

Op-amp power dissipation

I would like to use an LT1210 op-amp with a +/-12 VDC supply. The input is from a signal generator (10 Vpp, 400 Hz sine wave). The required circuit output is 5 Vrms (14.01 Vpp), 400 Hz and drives a ...
Ariel Narboada's user avatar
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0 answers
46 views

LHP zero in voltage buffer compensated opamp

I am observing a LHP zero for the following miller compensated opamp with a unity gain buffer in the miller feedback loop. I am not intuitively being able to analyze the source of this zero. Would ...
Anweshan's user avatar
2 votes
1 answer
65 views

Bias Voltage affecting op-amp at 0v

This question is a follow-up from the setup described here Recap: I am designing a circuit which is intended to map a signal in the 0-5V range to the 1.75-7.0V range. To do this I am using an LM317T ...
Jayson Okhman's user avatar
4 votes
5 answers
963 views

Unity Gain Amplifier Purpose

In layman terms, what is the main use and purpose of unity gain amplifiers? I am reading that it is used to "buffer high impedance sources" but I'm unsure what this means practically.
RL1's user avatar
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1 vote
2 answers
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Decoupling capacitors for operational amplifiers

when in the refence design of an amplifier (for example OPA856) we see the + sign in a capacitor schematic, does this necessarily means we should use electrolytic capacitors? If there is no positive ...
Andromeda's user avatar
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What circuit protection devices are needed for an automotive application? [closed]

I am designing a circuit for a automotive application which is meant to map voltage ranges between two sensors (ex. 1 sensor has an output range of 0-5V while the other has a output range of 1.75-7.0V)...
Jayson Okhman's user avatar
3 votes
3 answers
120 views

Selecting appropriate Opamp for RRO applications

I am designing a circuit which is intended to map a signal in the 0-5V range to the 1.75-7.0V range. To do this I am using an LM317T voltage regulator in conjunction with a TLC2272 Rail-to-Rail opamp. ...
Jayson Okhman's user avatar
0 votes
2 answers
85 views

How to modify this TIA amplifier in this scenario?

I want to use a photodiode in photovoltaic mode with a TIA amplifier and be able to set the gain with a feedback resistor and also minimize the dark current offset related and with certain linearity. ...
cm64's user avatar
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Operational amplifier layout- Controlled impedance

In the following picture, we can see a reference layout by Texas instrument for OPA838: I noticed, in the polygon on the top layer, they have used a specific gap=0.5 mm, I wonder if they used a ...
Andromeda's user avatar
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1 answer
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Connecting thermal Pad to the negative supply voltage

I want to use OPA856 and there is a thermal pad. In the datasheet it is mentioned that it should be connected to V-. In my configuration it is V- is -5v, but there is a very small copper region for -...
Andromeda's user avatar
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1 vote
1 answer
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Analog Devices Photodiode Circuit Design Wizard result

Regarding Analog Devices Photodiode Circuit Design Wizard tool, when I need BW of 100Hz with a feedback resistor Rf = 50k, I expect a required feedback capacitor value from the formula: Cf = 1 / (2πRf*...
cm64's user avatar
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3 answers
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Adding reference voltage to oscillator

I have designed a very basic Schmitt Trigger LFO. However, the power supply for the op amp has to be 9 and 0 V instead of 9 and -9V. For doing so, i supose that i need to add some voltage reference ...
miguelfuzz's user avatar
3 votes
6 answers
916 views

How can I create 4-20 mA current souce

I have one op amp based circuit that converts 4-20 mA from current sensor into 5-9 V DC. Right now I don't have any such sensor to test this circuit. I want to create new circuit that produce 4-20 mA ...
Bhushan Waghe's user avatar
6 votes
3 answers
280 views

Problem implementing a voltage divider with a buffer amplifier

I'm currently working on a project where I need to implement a voltage divider followed by a buffer amplifier to scale down a voltage signal by a factor of ~10. However, I'm encountering some issues ...
LeCarthique's user avatar
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1 answer
44 views

Confusion with the sum of open-loop gain and feedback attenuation

Regarding the following statement taken from here: Looking at amplitude response on the log plot, circuit instability occurs when the sum of open-loop gain and feedback attenuation is greater than ...
pnatk's user avatar
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2 votes
0 answers
95 views

Constant current feedback op-amp analysis

Above is the schematic for the convoy XHP35 flashlight driver. As you can see, the current control loop uses the op-amp as a comparator between a setpoint (low-pass filtered PWM output from a ...
roaibrain's user avatar
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0 votes
4 answers
80 views

Is this expression wrong about single/split supply op-amps?

I'm trying to understand why some op-amps are sold as "single-supply" even though it seems all op-amps can be used with single supply voltages. And I came across this paper which states: ...
user1245's user avatar
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0 votes
1 answer
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Buck converter Sim not working

I am having some issues getting a simulation of a buck converter I've been trying to design to work. For some reason the op amp (circled in Red) isn't seeing any voltage on either of its inputs (both ...
Bren's user avatar
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3 votes
0 answers
66 views

Whats the relation between RC time constant and the GBWP of an opamp?

If I'm not wrong, an opamp circuit's feedback resistor and capacitor dictates the response time of it. So in case we have the control over Rf and Cf we can set the response time. But in that case, ...
user16307's user avatar
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-1 votes
2 answers
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why is output of a voltage follower non zero [duplicate]

Why is the output of a voltage follower non-zero and equal to the voltage at the non-inverting terminal if the voltages at both the inverting and non-inverting terminals are the same?
Archan Archan's user avatar
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0 answers
62 views

Capacitance on op-amp input (inverting pin)

I have the following configuration for my amplifier, which is an transimpedance amplifier: I need to connect my transducer to the inverting pin of my amplifier by using a dip switch to be able to ...
Andromeda's user avatar
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5 votes
4 answers
471 views

Ground in differential opamp situation

I have a setup like such in the provided schematic. The idea is that I do have a -2.5 to 2.5V signal which I'd like to convert to a signal between 0 and 5V. How should I connect my opamp? Should the ...
Mart's user avatar
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0 votes
3 answers
152 views

Sine to square wave circuit

Following this question Sine wave to square wave - Schmitt trigger, I am trying to simulate a sine to square wave circuit using an op-amp. I am playing around with components values to see their ...
JeanB_01's user avatar
0 votes
1 answer
91 views

How to measure overshoot of an op-amp without having an oscilloscope

I need to measure the overshoot of an op-amp but have no oscilloscope or other measuring device available. I should therefore have a circuit to do so. I have created an input pulse and want to apply ...
Fateme's user avatar
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0 votes
1 answer
56 views

High distortion problem with common source MOSFET amplifier

I am simulating this circuit, it is a MOSFET common-source amplifier biased using the drain-to-gate resistor configuration. MOSFET parameters are: VTO = 1.25V, Lambda = 0.005, Kn = 0.065 (A/(V.V)), W/...
ferer's user avatar
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3 votes
2 answers
869 views

Tantalum capacitor for op amps

Normally for opamps supply voltages, it is suggested that there should be (100 nF + 2-10 uF) on the positive and negative supply pins. The second capacitor which is in range of uF should tantalum? Or ...
Andromeda's user avatar
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0 votes
3 answers
178 views

Can I get very high current (1000s of amps) using multi stage op amps?

If I wanted to build a power supply that could output 1000s of amps at low adjustable voltages, could I do this by using multi-stage op amps? Is this the best way to build a high current adjustable ...
jlaufer's user avatar
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0 votes
4 answers
152 views

General Formula for the inputs to an op-amp?

I was wondering if there is a single formula that expresses the voltage to the inputs of an op-amp, lets say an inverting op-amp, in every case? In the example attached, I understand how the ...
5eamus's user avatar
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0 votes
2 answers
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Calculating output impedance of this op-amp

Let the following schematic from pages 9/10 of "link" I'm tasked to calculate the output impedance so we used this circuit which is equivalent to the under picture model, with \$R_L = VR1 + ...
Knowledge Seeker's user avatar
4 votes
2 answers
891 views

Please help check why my opamp calculation has a different answer from my lecturer's

My Lecturer's Solution Why is the first equation = 0? Couldn't there be current sinking into the Vee rail of the opamp or being sourced out from the Vcc rail of the opamp and then outputted into the ...
MikeWazowski's user avatar
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Is my approach correct for this task?

In this circuit, we're using a non-inverting amplifier. I need to determine the output voltage (V(OPV+)) and the voltage gain (Ak). First, I calculated the total resistances for R1 and R2, as well as ...
caramello209's user avatar
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1 answer
46 views

Wiring non-inverting opamp

I have an Texas Instrumentes OP07 and am trying to wire it as non-inverting amplifier. I have made some photos. On the "near" photo you can barely see the "orientation circle": I ...
Hansebenger's user avatar