Skip to main content

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.

Filter by
Sorted by
Tagged with
0 votes
1 answer
38 views

LT6268-10 Opamp Oscillation and Offset

Below is my Photodiode-OpAmp circuit that is configured as Transimpedance Amplifier. When I put both inverting and non inverting into ground, no signal is coming out. However when I connect ...
LifeIsBeatiful's user avatar
0 votes
1 answer
44 views

Op-Amp for microelectrodes in PBS conductive solution

I am using micro electrodes in a conductive solution (PBS: Phosphate Buffered Saline) and I would like to be able to measure the voltage with a National Instrument measuring device (PXIe6345). I apply ...
Jad Rabhi's user avatar
1 vote
1 answer
40 views

How to set a timer for this circuit?

I have this circuit however I need to make a timer that works for 2 - 2.30 hours, so I have this circuit here: But I need to know how much should R1 and C1 be approximately to fulfill this job? Note: ...
Hazardous Voltage's user avatar
0 votes
2 answers
52 views

Need help opamp or optocoupler?

What is the best route? Optocoupler or opamp (if opamp, which one?) I need to reduce this 5.8V pulse generator to 0.84V Have an automotive application I am trying to find a solution. Basically I want ...
Matthew Hussey's user avatar
3 votes
3 answers
350 views

Constant volatge at the output of LM311

I made a PCB based on the following schematic. The inputs of the comparator work as expected (i.e., the capacitor voltage or the voltage at the non-inverting pin gradually increases and, after a few ...
Hamid Saneie's user avatar
0 votes
2 answers
31 views

Strange asymmetric saturation with ADA4099

Good afternoon — my first question here, I hope I follow all the rules... So, I am trying to design a series of filters with op-amps that have a shutdown pin, using only 0 ­→ 3.3V supply and an analog ...
Rmano's user avatar
  • 287
-2 votes
0 answers
61 views

Audio amplifier for a physics experiment, how do I make it? [closed]

The experiment includes a mic taking in sound(2KHz-4KHz) and sending it to a DSO. I need an audio amplifier circuit in between that to amplify the signal so it would be visible properly. The ...
Aether Void's user avatar
0 votes
2 answers
74 views

What type of amplifier circuit do I need to drive a piezoelectric ultrasound transducer?

I would like to drive the following piezoelectric transducers at 200 V or their maximum voltage (60-1000 V): https://www.manorshi.com/16mm-Dog-Repellent-Ultrasonic-Transducer-25khz-Detect-Sensor-...
Alex's user avatar
  • 9
2 votes
2 answers
82 views

TL072CP non inverting circuit doesn't amplify

I am using TL072CP op amp in inverting mode to amplify guitar signal. This is the circuit I have made: I assembled it and even when changing resistors of different values and trying out different ...
vjeran bach's user avatar
1 vote
2 answers
59 views

How to simulate for the Gain of opamp Bridge Differential Amplifier?

Hi experts, I have this circuit, with a bridge connected to an op-amp in differential form, and I want to simulate it for the Gain of the circuit in PSPICE. I have found it's gain by hand, which comes ...
Vibhav shivadeker's user avatar
0 votes
1 answer
52 views

Audio Codec Input/Output Channel Stages

I am planning to build a PCB for a Eurorack Modular Synthesizer, incorporating an STM32 for DSP and a bidirectional Audio Codec like the TLV320AIC3104 to handle the ADC/DAC. Eurorack audio signals ...
95lux's user avatar
  • 1
5 votes
7 answers
959 views

Infinite output impedance in amplifier, instead of 0?

The question asks: "Exercise 14.5 Assume an ideal op amp and use the summing-point constraint to find an expression for the output current io in the circuit of Figure 14.14. Also find the input ...
Nitai Michalski's user avatar
0 votes
0 answers
60 views

Applying KVL in op amp with floating source

From my understanding, the solution first applies the summing point constraint even though there is no ground on the non-inverting input, leading to 0V on both inputs. But how do they apply KVL across ...
Nitai Michalski's user avatar
6 votes
4 answers
321 views

Is it correct to apply KVL through the 2 inputs of an op amp?

The question asks; "P14.25 Analyze each of the ideal-op-amp circuits shown in Figure P14.25 to find expressions for 𝑖𝑜. The top part is the question, the bottom is the solution from the ...
Nitai Michalski's user avatar
3 votes
2 answers
217 views

How are opamp node voltages being set in the following circuit and what is the use of the diode configuration?

I am using a PCB which has the following opamp configuration implemented. It's supposed to be a precision buffer for the source V3. I accidentally connected the source V4 as well and observed strange ...
needbrainscratched's user avatar
4 votes
3 answers
489 views

Issues with ICL7660 ICs from eBay - Overheating and Failure

I recently purchased several cheap ICL7660 ICs from eBay to use in an OpAmp circuit. Unfortunately, I've encountered issues with these components, specifically overheating and subsequent failure. Here ...
Special.Guest's user avatar
0 votes
2 answers
86 views

What is the maximum dBu I can send into a microphone input in this schematic?

The schematic below is from the Icom 9700 radio service manual (page 80). I would like to feed this input from a mixer board's ALT-3/4 outputs, and I want to avoid blowing the TS462 microphone preamp ...
KJ7LNW's user avatar
  • 2,180
0 votes
1 answer
64 views

Part name of this IC - "LLA#537"

I want to know the part numbers of the components marked as shown in the attached image.
Bang Duong's user avatar
4 votes
1 answer
188 views

Part name of this IC - Analog Devices, 8-pin, "S 6B" A 06" "C 42"

I want to know the part numbers of the components marked as shown in the attached image.
Bang Duong's user avatar
1 vote
0 answers
52 views

Need help analyzing sability of op-amp in a current source in LTSpice

I have to perform stability analysis on an op-amp (AD8671) which is being used as an op-amp in the circuit attached. I am using LTSpice to perform this. My approach is to give a 1V AC small signal at ...
Riyan Dahiya's user avatar
-1 votes
2 answers
70 views

Opamp inverting and non inverting issue

I want to get inverting and non inverting square wave at the same time. I am using EL2444 quad op amp, gain not required. My input is approx. 550 kHz, 50% duty cycle square wave. I assume that I will ...
ksoni's user avatar
  • 3
0 votes
0 answers
42 views

PCB track widths for optimized layout for operational amplifiers

When designing a PCB track, its width, length, and stack-up can introduce inherent inductance and capacitance. These parasitic elements can significantly impact the performance of sensitive circuits, ...
Andromeda's user avatar
  • 557
2 votes
1 answer
129 views

About the vout of a different opamp circuit

I greet everyone in the community, While trying to solve such an opamp circuit on paper, I could not find the formulation, I simulated it, but I could not find the value in the simulation. I find ...
smartony152's user avatar
2 votes
1 answer
62 views

port 7 and port 4 in the opamp that I can't make sense of

I greet everyone in the community, I have a sample circuit like this and this is how I simulate it. theoretically X and B values on paper; X = 1.5 VOLT B = 3 VOLT as But in the simulation I find the ...
smartony152's user avatar
3 votes
2 answers
90 views

Related to the opamp question solution (a point I don't understand in the difference amplifier)

I greet everyone, I am in the process of learning opamps, I got stuck here while solving a question about the difference amplifier. When finding the Vo value, we do the following operation; \$V_O = \...
smartony152's user avatar
1 vote
1 answer
63 views

How would one calculate the transconductance of the FETs in this circuit?

I was given formulas to find the transconductance (gm) of the FETs using IDSS, VP and VGS, however, none of the ways I tried them leads to the correct answer (given as 2,55mS).
Alonso Vargas Sabean's user avatar
0 votes
0 answers
45 views

Op-Amp oscillations when controlling P-MOSFET Vgs

My background is digital design, I guess the answer is obvious for all here, but not for me. I am studying example of analog physical layer for USB 2 protocol which I found in this paper. Also ...
converged_hyppo's user avatar
1 vote
2 answers
272 views

Solving complex opamp circuits

I'm having some troubles understanding how to solve complex circuits with opamps like the following: During my lab course (I'm a physics major) the professor showed us the solution of very simple ...
deomanu01's user avatar
1 vote
1 answer
33 views

How to gemerate a square wave circuit with lower level at 20V and higher level at 40V with several DC power supplies

I would like to ask for help to build a circuit that is able to generate a square wave with a lower level of 20V for 1 ms and an upper level of 40V for 9 ms. It is quite challenging for me as it needs ...
Eddie Zheng's user avatar
6 votes
5 answers
2k views

What is the purpose of the BJT in this circuit? [closed]

What is the purpose of Q1? Is it just to amplify the current? What region will Q1 be operating in and how do I determine this?
Harrison's user avatar
0 votes
0 answers
16 views

AD8232/AD8233 not working for sEMG

I am working on an sEMG circuit using the AD8232 and cannot figure out what is going wrong, the circuit isn't outputting the correct signal when connected to the forearm. I am using the 3 lead ...
user2608683's user avatar
0 votes
1 answer
78 views

How to Properly Select Resistors and Capacitors for a Voltage Reference Circuit with BJTs

I am working on a reference voltage circuit and I am having trouble when selecting the appropriate resistor and capacitor values. The circuit involves OP07 operational amplifiers and transistors (...
Cheche Romo's user avatar
1 vote
1 answer
93 views

Why does this two stage op-amp not work?

I was trying to simulate a two stage op-amp I had just learned about. I am going step by step i.e. as you can see from the schematic I have started with ideal current sources. I know that this op-amp ...
Koustubh Jain's user avatar
0 votes
1 answer
81 views

50 Hz 2.5 Vpk-pk signal amplification [closed]

I get a 49.8 Hz 2.5 Vpk-pk sine signal. I want to amplify this signal and drive a 22 Ω resistor. Do you have a chance to provide an example of amplifier circuit design? As a result of this upgrade, ...
Ozan AKYOL's user avatar
1 vote
4 answers
97 views

Instrumentation amplifier input bias currents direction and error

I am trying to understand how the input bias currents flow in op amp and instrumentation amplifier circuits and what errors they create. I came across a circuit that looks like the following: ...
Robert's user avatar
  • 49
-1 votes
1 answer
93 views

Chinese clone op amps , not talking about counterfeit / fake op amps [closed]

I already know about Chinese counterfeit / fake op amps, AKA getting a totally different op amp and re-etching the IC or faulty op amps going to china and these op amps getting sold. But what about ...
Michael Weaser's user avatar
1 vote
1 answer
50 views

Voltage Divider + Unity Buffer as a power supply

I'm working on an application where I need to step down a 3.7V LiPo down to a 1.0-1.5V for an embedded device that takes AAs (effectively an AA-to-LiPo conversion kit). In order for "low battery&...
Felix Jen's user avatar
  • 217
2 votes
1 answer
53 views

IRF540 MOSFET Replacement [closed]

I am looking for a drop-in replacement for an IRF540 MOSFET with a more robust transistor. I want to find a MOSFET with a larger, Safe Operating Area because it is the pass element in a linear 14-volt,...
Dereck's user avatar
  • 652
1 vote
1 answer
61 views

Transfer function of differential controller

I found an op amp circuit that is designed to be a derivative controller (D-controller) simulate this circuit – Schematic created using CircuitLab and the transfer function $$ \frac{V_o}{V_i} = ...
vvttr's user avatar
  • 41
2 votes
1 answer
87 views

Implementation of Circuit in AN104 for Load Transient Test

I have been testing the transient response of line regulator simply with a MOS and the resistor, this method, however, cannot generate arbitrary current and the current is not accurate. To improve the ...
cc Lau's user avatar
  • 23
0 votes
0 answers
94 views

TPA6111A headphone amplifier oscillation

I came up with this simple circuit to mix two small audio signals (about 0-400mV) coming from a pair of DAC output channels, and provide an headphone output with the help of the TPA6111A2. I ...
Dimitri Petrucci's user avatar
1 vote
0 answers
69 views

Amplification Calculation

I have a question about how to calculate the amplification of amplifier. Here is the circuit: The equation provided by in the datasheet for calculating the output is: CURphase = VOFS - amplification *...
WC_iOS's user avatar
  • 19
1 vote
1 answer
56 views

Wideband Photodiode Amplifier (>= 50MHz) and Obnoxiously Big Input Bias Currents of Current Feedback Amplifiers

I'm toying with the idea of building a >50MHz Bandwidth Photodiode Amplifier, built around a 1GHz AD8009ARZ Current Feedback Amplifier. I got two photodiodes that have a bandwidth exceeding 1GHz. ...
Virgil_Tibbs's user avatar
1 vote
1 answer
56 views

Why does LTC6253-7 not perform properly on LTspice?

I am working with LTC6253-7 op amp which should have a bandwidth of 2 GHz but when I simulate the output for a follower and the output is being severely attenuated. Is there a technique that must be ...
the_circuit's user avatar
0 votes
1 answer
41 views

What is this pin for on LTC6253-7 [closed]

I have tried looking at the datasheet but can't seem to find any information on this pin.
the_circuit's user avatar
0 votes
2 answers
162 views

LTSpice simulation produced different results of phase margin when using step-signal % overshoot technique vs loop analysis technique

I am working on a class AB amplifier circuit to that can output both AC and DC current, controlled by an op-amp with feedback from the final output. The output will be driving an 50uH inductor. The ...
Zhi's user avatar
  • 41
1 vote
0 answers
137 views

Circuit works only when oscilloscope probe is connected and does not work otherwise

I have built the circuit shown below. The problem is that the circuit only works when I connect oscilloscope probes between node-A and the ground. If I remove or decouple the probe-ground from the ...
UTs's user avatar
  • 11
4 votes
2 answers
487 views

How is it possible to supply an LM833D with +12V and -8V supply?

I was studying a Philips CDR-765 circuit when I came across an output driver circuit consisting of an LM833 opamp supplied with -8VDC on the 4th pin and +12VDC on the 8th pin. This is the first time I ...
kunal pandit's user avatar
0 votes
1 answer
28 views

Keep the circuit stable even without the input capacitance on inverting pin of a transimpedance amplifier

I have designed an transimpedance amplifier for an ultrasound transducer as follows: Ultrasound transducer feature: C=1nF, R=1.2K, working frequency between 2-3 MHz When the transducer is connected ...
Andromeda's user avatar
  • 557
2 votes
1 answer
117 views

How to stabilize this op-amp circuit?

I have a "JFET enhanced" op-amp circuit shown below: "JFET Enhanced" op-amp circuit Similar to the circuit used in the TI app note: App Note The circuit looks stable in SPICE with ...
Chris192's user avatar

1
2 3 4 5
171