Questions tagged [unity-gain]

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Unity gain differential amplifier null adjustment circuit not working

I have a differential op amp that I believe I have set up as a unity gain differential amplifier. When I measure the potential difference across pin 6 and ground and adjust the 5K trimmer ...
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1 answer
106 views

Stability of the op-amp?

I am confused if the below amplifier will be stable or not when it acts as unity gain amplifier ( with a feedback factor of 1) ? My analysis: PM = zero from the bode plot , so the system is stable ! ...
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1 vote
2 answers
105 views

How to use voltage follower after BJT amplifier in LT SPICE

Hello in a circuit I'm trying to create, a voltage follower is placed at the output of a BJT amplifier in order to create a buffer from the rest of the circuit. When I do this with the "ideal op-...
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4 votes
4 answers
301 views

Unity-gain bandwidth circuit with uA741 op-amp

Q: Using Op-Amp uA741, design an amplifier that offers a passband gain of 40dB with a minimum bandwidth of 20kHz. The current through any resistor in the amplifier should not exceed 10 mA. Include the ...
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1 answer
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Help in explaining op-amp voltage follower behavior

In the following circuit, I'm having a hard time figuring out the reason for the output. The op-amp is the OPA1662, powered at 3.3V. It is rail-to-rail and unity stable. When R?/Rth is not installed,...
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2 votes
2 answers
74 views

Voltage divider high resistace

I need to build voltage divider to measure the battery voltage (7.3V) using max 3.3V ADC. As the device most of the time spends in the sleep mode (<1uA), the current drawn from the battery should ...
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1 answer
105 views

Voltage follower output current

We know that voltage follower will have a nonzero output current. How do I solve for this value? Let's say I am using an LM358 op amp to implement the buffer (unloaded), do I just use the Output ...
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0 votes
3 answers
165 views

Unity gain buffer giving DC out

I am feeding square wave (0-5V) at 1kHz through a AD713JNZ op amp which I have wired up as a unity gain buffer, but I'm getting 5V DC on the output: What am I doing wrong?
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3 votes
2 answers
670 views

Significant error with unity-gain feedback op-amp

I used this OP97 op-amp to make a simple unity-gain feedback circuit. I would expect the output in this case to follow the input with very little error, however the output is actually measured at \$ 2....
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2 votes
3 answers
2k views

How to design a 2nd Order High Pass Butterworth filter with a cutoff frequency of 0.5 Hz? [closed]

c1=c2=10µf, R1? R2? using the unity-gain Sallen-key topology what should I do?
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1 vote
2 answers
91 views

Misunderstanding of calculating gain of amplifier

I’ve been reading in my textbook that the gain is Gain= Vout/Vin= 1+ Rf/Rin However, what if there isn’t a resistor like this amplifier? Would it be 1V/V or 2V/V? Or am I totally misunderstanding this?...
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0 votes
3 answers
146 views

protect op amp input from overvoltage from piezo sensor

I use a piezo to register the moment of a knock via a micro controller's analog in (1.8V Max) So far I used the scheme in the figure without any diodes. This works so far, but depending on the knocks ...
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1 vote
1 answer
773 views

What is the difference between the transition frequency and unity-gain frequency?

What is the difference between the transition frequency and unity-gain frequency? I hear these terms being used all the time and I thought they referred to the same thing (the frequency at which the ...
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2 answers
94 views

Smoothing capacitor for half wave rectification

I'm trying to implement a half-wave rectifier using just a diode. I'm using a unity gain opamp for isolation from the mains. At the output of the opamp, I'm using a smoothing capacitor to get a DC ...
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  • 143
1 vote
1 answer
478 views

Voltage Follower - OPAMP

I am going through an OPAMP Voltage follower/Buffer Circuit. I have 1 question regarding this Voltage follower circuit using OP-AMP and 2 questions in general regarding OP-AMP: Let's say my Vcc ...
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0 votes
1 answer
493 views

unity gain buffer large input offset voltage

I'm using a unity gain buffer to drive a power amplifier voltage reference. Here's a schematic for the buffer configuration. The op-amp in question is a LMV321. I've set the voltage divider at the ...
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0 answers
174 views

Help refining a current control loop circuit

As a follow up to this question. (Sorry if this linking other posts is wrong. I'm new to forums) Will this design for an XHP70.2 LED Driver with arduino control work to the params specified? TL;DR: ...
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1 vote
2 answers
973 views

Op-Amp Unity Gain Frequency

I'm tasked with finding the unity gain frequency of an op-amp using the datasheet specs provided to me (just a homework exercise, not a real op-amp). There is no direct spec given for "Unity Gain ...
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0 answers
144 views

Output different from input in unity-gain op-amp (voltage follower)

I am using an LM358p op-amp as a voltage follower (unity buffer). I have a battery as a 9V voltage supply, two resistors for a voltage divider so that the non-inverting input of the op-amp gets 5.6 V....
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1 vote
1 answer
136 views

What do you call unity gain? 1V/V or 1V/V plus a small tolerance?

I designed a two stage single ended op amp with an internal frequency compensation. There's a minor problem that I noticed in my loop gain transfer function. I forced the gain to reduce to around 0....
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0 votes
2 answers
451 views

How do parallel resistors and capacitors reduces frequency peaking in opamps?

I'm trying to understand a schematic from the front end of an analog discovery scope. It uses an AD8066 opamp, and has a resistor and capacitor in parallel on the inverting and non-inverting terminals....
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1 vote
0 answers
105 views

Does a Microcontroller act as a Capacitive load or resistive?

I'm designing a unity gain buffer (IC MCP6002) and in the datasheet, it says that a small series resistor is required at the output, if the load is capacitive and is >100pF. The input of the buffer ...
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2 votes
1 answer
434 views

Unity Gain Phase Splitter- Why outputs have different voltages

I’m trying to calculate the values of the biasing resistors for this phase splitter circuit. (I know the actual values of the resistors, but I just wanted to manually work it out). When I made the ...
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  • 273
11 votes
2 answers
2k views

Expected and actual unity gain bandwidth LM324N

I have an LM324N configured as a unity gain voltage follower. The split rail power supply +/- 4.5V is provided using AA batteries. I am aware that better opamps exist, but this is for study purposes ...
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  • 357
2 votes
1 answer
329 views

Simple op-amp frequency response

In my textbook, there are two interrelated equations. 1. wb = wt / (1 + R2/R1) 2. wb = wt / Ao where ...
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2 answers
504 views

Opamp Voltage Follower Oscilates

I am trying to measure voltage across a 0.1R shunt resistor. When i measure voltage between input1 and input2 with multimeter i can see 10 mili volts. When i connect input1 to a voltage follower in ...
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2 votes
1 answer
453 views

High freq OP-AMP voltage follower is ringing and is unstable

I try to design analog buffer for the 5MSPS STM32 ADC. I try to use TSH114IDT or CLC4007 opamps ( I need 8 in total). I have done so far: Tried the design below with or without some of the elements - ...
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3 votes
2 answers
763 views

LM358 opamp unity gain cap

I'm using an LM358 op-amp for unity gain (feedback to V-). However, I'm getting some unexpected results. When Vin is from 0v - 3.75v, op-amp output is as expected 0 - 3.75v. However, when Vin is ...
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0 votes
1 answer
4k views

Unity negative feedback controller, why does Gain K go on the numerator of the transfer function

I have a system G(s). It has no zeroes, but some poles. When applying unity negative feedback, with a static gain K, why does K remain on the numerator of my transfer function T(s) which describes ...
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  • 115
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1 answer
197 views

Op-Amp for the 50MHz unity gain voltage

I have tried many different op-amps in many configurations. But almost always I am getting a very unstable configurations: https://youtube.com/watch?v=ybhDs-dw6j8 https://youtube.com/watch?v=...
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2 votes
2 answers
597 views

How do you use Gain Bandwidth Product to estimate bandwidth at different gains?

I was doing a question related to the dependence of op amps on frequency.This question is from 2nd year electrical engineering micro electronics by sedra smith. Here is the question: So there is a ...
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1 answer
407 views

Can any Op-Amp be used as a voltage follower(buffer)?

I have a square wave, to which I have to add a buffer. The Frequency of the square wave is around 10MHz. I am new to Op-Amps, but I have read that I need a high slew rate. Can I use any Op-Amp(with ...
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2 votes
2 answers
2k views

Adding offset voltage to sensor signal

I have a pressure transducer outputting 0-5V which is sampled by an ADC with a 0.5V minimum input voltage. I need to offset the sensor output voltage by a fixed voltage of 0.5V. I've looked at an op ...
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  • 197
3 votes
3 answers
697 views

500V unity gain buffer

I am currently in the process of designing a high-voltage bias supply for use with an ionization chamber. The voltage source itself is taken care of however I need a unity buffer to drive the guard of ...
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3 votes
1 answer
2k views

Op-Amp with Voltage Controlled Gain and Unity DC Gain

I have a car seat motor that I am driving via PWM and am aiming to measure its position by counting the minor variations in voltage across a current sensing resistor attached to the low side of a FET ...
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0 votes
1 answer
1k views

Unity Gain Op Amp Configuration: Stability?

I'm planning to use the ADA4610 in unity gain configuration as a current buffer for a high precision (16-bit) DAC chip. The chip is labeled as being stable in the unity gain configuration. I currently ...
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  • 191
-2 votes
1 answer
73 views

How does op-amp gain = 1 - error?

Please see attached image. How does the voltage gain end up being equivalent to Av = 1-error? Thanks
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0 votes
1 answer
451 views

Follower current source?

I need advice on a problem I'm having I need a follower to transmit an AC signal into a low impedance load which is the cathode of a triode but I also need it to be an adjustable current source to ...
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1 vote
0 answers
60 views

Unity Op amp Question Gain and Resistances

The Question asks what is the gain in dB and also what are the input and output resistances I know the gain is 1 so dB that would be equal to 0 dB But I am confused on how to find the input and ...
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1 vote
2 answers
779 views

Unity gain op amp gives static, incorrect output

I have the circuit shown here: where I'm using a switching regulator (not the linear 78xx shown) to provide me with 5V to power an Arduino and a little more circuitry that the Arduino is monitoring. ...
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2 votes
1 answer
1k views

Sine wave distortion in simple op-amp circuit- bypass capacitor?

I've built a simple unity-gain buffer op-amp circuit from the UCSB lab here, with a 12V power supply and a 1V, 1 kHz input sine wave. simulate this circuit – Schematic created using CircuitLab ...
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  • 497
0 votes
1 answer
2k views

Practical Opamp integrator problem

The opamp has an unity gain of 1 MHz.So when the resistor in parallel acts a feedback to bias the opamp stable.So if not for the capacitor,the circuit would have been a inverting amplifier with gain ...
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2 votes
1 answer
411 views

Terminating unused unity-gain Unstable op-amp

I am trying to terminate the unused unity-gain unstable op-amp. I have tried to terminate it with the typical unity-gain stable configuration (http://www.maximintegrated.com/en/app-notes/index.mvp/id/...
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