Op-amp Definition and 217 Threads

  1. J

    Engineering Op-Amp circuit to supply constant power

    Homework Statement see image Homework Equations The Attempt at a Solution I can make 2 different circuits to solve this. However, Using just op amps and resistors I am not sure how to make a single circuit that could do this
  2. xortan

    Low-pass filter with unideal op-amp

    Hello, I am designing an op-amp to be used as a low-pass filter and am using a TLC271. I have attached an image of the topology of the circuit. I found the transfer function to be G(s) = Y(s)/X(s) = 1/(10^-4s + 1). I plotted the bode plot in MATLAB and have attached the result in the...
  3. H

    Design Op-Amp Bandpass Filter for 500 & 1500 rad/s

    Homework Statement Select component values to design for corner frequencies at 500 rad/s and 1500 rad/s. Homework Equations KCL, transfer function The Attempt at a Solution Gain: [1] G = 1 + \frac{R_{A}}{R_{B}} Voltage division: [2] V2 = V1\frac{R_{2}}{R_{2}+1/sC_{2}}...
  4. R

    Determining the gain of an op-amp with feedback?

    Homework Statement Homework Equations I have two "golden rules" I was given which are "no current into the op-amp" and V_{-} = V_{+} and the open loop gain is infinite Basically my notes and textbooks are leaving me with pretty much nothing though The Attempt at a Solution tried...
  5. H

    How Do You Design an Op-Amp Bandpass Audio Filter with LED Indicators?

    I am attempting to build an Op-Amp circuit in which a sinusoidal input is used. Below is the description: An active, op-amp bandpass filter circuit for audio frequency inputs. The implemented filter circuit must provide a maximum gain of 14 dB inside the pass-band and less than 9 dB of...
  6. J

    MATLAB How to simulate Op-Amp in MATLAB

    Good day. Could anyone tell me how to simulate an equivalent Operational Amplifier in Simulink? I read somewhere that I had to do it with 2 adders and a gain block, but I don't know how. Thanks.
  7. M

    Find Vout for Op-Amp Circuit with Attached Image

    1. Please refer to attached image. 2. The attempt at a solution. I noted that Vb was grounded and would therefore be equal to 0 and because one of the two op-amp rules states that Va = Vb, both will be equal to 0. I wrote an equation at node Va: [Va - Vin]/R1 + [Va - Vout]/R2 =...
  8. G

    Engineering Calculating reliable bits of op-amp circuit

    For some reason I can't get the answer right. It is given as 6 bits but I calculated it to be 5. What am I doing wrong?
  9. S

    Ideal Op-Amp: Voltage Gain Formula | R1, R2, R4

    Derive a symbolic expression (i.e., a formula containing symbols R1, R2, ..., etc., andarithmetic operators instead of numerical values) for the voltage gain of the amplifier What I am stuck at is the two nodes on each side of R4 I initially disregarded the node to the right of R4, which...
  10. H

    Engineering Calculating R2 for 5W Output in Op-Amp Circuit - Homework Help

    Homework Statement Calculate the value of R2 required to deliver 5W to RL if Vin equals 5V. Homework Equations Vout=iRL P=Ri^2 The Attempt at a Solution I started by using KVL for the input loop, noting that current is going counter-clockwise: Input loop: iR2-Vin=0→R2=Vin/i...
  11. O

    Engineering Op-amp circuit peak current and swtiched circuit transient

    Homework Statement I have uploaded the questions in the attachment. I am having trouble with 2. e,f and 3.c untitled.png is the parts that I am having trouble with. untitled1.png and untitled2.png is the entire question. Homework Equations y(t)= steady state+transientThe Attempt at a Solution...
  12. E

    Analysing Non-Inverting Op-Amp Circuit: Questions & Answers

    I'm supposed to be analysing this circuit to go with my lab report. However I haven't seen a circuit like this. First off I'm not sure what the symbol is on the top left resistor (15kΩ//1.2kΩ) means. Secondly I'm used to doing inverting op amps and they generally don't have many/ any...
  13. U

    Help Find an Op-Amp for Popular Electronics Project

    Hey everyone, Whelp, I've had this project dancing around in the back of my mind for a good six months now and I'm here to ask for some help. I'd like to build this biofeedback device from an old issue of Popular Electronics...
  14. C

    A question on ideal op-amp (finding a current).

    Homework Statement I had an exam question on ideal op-amp asking to find a number of unknowns. I found them all except that I'm skeptic of my attempt in finding the output current which is symbolized on the circuit (io), so I have come to ask to throw my skepticism away. See the circuit below...
  15. Femme_physics

    Op-Amp Trick Questions: Formulas for Av and LED Circuit Solutions

    Homework Statement http://img502.imageshack.us/img502/4082/vddvss.jpg I'm asked to 1) Develop a formula for Av = Vout/Vin And 2) If the LED was flipped the other way, what must we do for for the rest of the circuit so current would still flow through it The Attempt at a...
  16. M

    Engineering Set time delay for a comparator Op-amp circuit

    Homework Statement [See attached diagram] I'm trying to design a circuit that connects to the input terminals of the noninverting input of this comparator circuit such that: -The input to my circuit consists of a SPST switch and a 9 volt battery -When the switch is thrown on, there would be a...
  17. P

    Op-Amp Slew Rate/Gain-Bandwidth Product

    Question The op-amp selected for the unity gain inverter, has a gain-bandwidth product, and maximum slew rate at its output of 1V/μs[/b] (i) Justify the statement that a high gain-bandwidth product necessarily leads to a high slew rate (ii) The phase sensitive detector is expected to operate...
  18. M

    Engineering Op-Amp Circuit Help: Voltage Follower & Multisim Guide for Homework

    Homework Statement in the attachment Homework Equations The Attempt at a Solution for q.1) its a voltage follower non-inverting Vcc has to be greater than 5V for the zener diode work? formulas? q2) does anybody know how to use multisim ? if i copy the figure in multisim...
  19. E

    Convert 1-5V to 4-20mA: Which op-amp ?

    So i found this post about voltage to current conversion. http://www.allaboutcircuits.com/vol_3/chpt_8/7.htmlhttp://www.allaboutcircuits.com/vol_3/chpt_8/7.html It talks about how to convert 1-5V to 4-20mA which is exactly what I am trying to do. I have attached the circuit which I am...
  20. R

    Protecting an LM324 Op-Amp in a Vacuum Tube Deflection Amplifier

    Hello. Here joined is the schematic of a small deflection amplifier. Outputs H0 & H1 are connected to electrodes placed in a vacuum volume. These outputs are protected by varistors. High voltage to collectors is 200 V DC. Sometimes, not very often, the head Op-Amp (LM324) is burnt. The only...
  21. Femme_physics

    Engineering What is the name of this op-amp circuit arrangement?

    I know this is a comparator, but I am asked for the name of this circuit. Can I just say a comparator circuit, or a comparator op-amp? Or is there a specific name for this circuit arrangement?
  22. D

    Lower DC voltage on single supply op-amp

    Howdy, I'm using the opa2350 op amp to amplify a <1mV signal by 2000. The problem is I want to have a greater gain (either second stage or larger feedback resistor) however the DC level is reaching too high so that it reaches over 2 V, and I need it under 2 V in order for a digital read into an...
  23. G

    Understanding the Virtual Earth Approximation in Op-Amps

    Homework Statement I'm studying op-amps at the moment, and I came across a statement and I don't understand it. 'To understand how the inverting amplifier works, you need to understand the concept of the virtual Earth approximation. In this approximation the potential at the inverting input...
  24. G

    How does negative feedback in an op-amp work conceptually.

    Consider an op-amp in which there is a DC voltage of 100mV for example applied to the non-inverting (positive) terminal of the op-amp and the negative terminal of the op-amp is connected to the output directly. Also take the voltage supplied to power the op-amp, Vcc, to be 15V and the gain, A...
  25. Femme_physics

    Who is Right: Op-Amp True or False?

    True or false: In the following circuit no current flows through R since Vout equals Vin. http://img10.imageshack.us/img10/2263/thehellisthat.jpg I say TRUE because it's the same as Voltage follower My classmate disagrees with me, says it's false, saying "if vout passes through a...
  26. Femme_physics

    What type of op-amp is being used in this circuit?

    Homework Statement http://img38.imageshack.us/img38/8373/circuit950.jpg At first I thought a comparator, then I noticed a line connecting the Vout and the lines that connect to V- and V+, so it can't be a comparator, can it? I don't see any other option... As far as the question, I...
  27. S

    Op-Amp Frequency Response Theory

    Homework Statement We did a lab analyzing this inverting, negative feedback circuit for a 741 op-amp: We measured the closed-loop gain and phase shift of the signal for several values of the input frequency with R_2/R1=1000,R_2/R1=100 and R_2/R_1=10. The gain curves all looked like...
  28. B

    Audio amplifier using only 1 op-amp [single supply]

    As the thread suggests, I am trying to amplify the signal from a microphone. Now, I have a circuit which uses 2 op amps with dual supply. That circuit works pretty well. I have to make now, a amplifier using only one op amp, single supply. The sound itself isn't of much...
  29. Femme_physics

    Engineering Electronic circuit with Op-Amp, Switch and Diodes

    Homework Statement http://img689.imageshack.us/img689/6668/mycircuit.jpg Given a circuit that includes Operational Amplifiers, double-switch - S, for two situations, 1 and 2. Type of switch - DPDT - Double pole double throw. Two diodes and two lightbulbs, L1 and L2. Given: Voltage...
  30. B

    How Do Zener Diodes Impact a Triangle Wave Op-Amp Generator?

    Well another op-amp thread, while the other one is being cooked. http://pokit.org/get/a09120280ee2f6b6e3de7a99989b8bd9.jpg To speed you up, this is a triangle wave op amp generator. It generates a triangle wave at U2. In general I understand how the circuit works, but from the engineering...
  31. B

    Pulse-with modulation using op-amp.

    http://pokit.org/get/c2d0bb4355d353d0ff5bc47c7158ce45.jpg Suppose we have an op-amp configured as a comparator. At -ive lead, we are sending the carrier wave, specifically in my example, triangle wave. At +ive lead, we are sending the input signal, the one that we want to modulate...
  32. Femme_physics

    What is this unique op-amp's name and how do I find Vout?

    Homework Statement http://img16.imageshack.us/img16/9341/shtoeta.jpg Find Vout. Homework Equations http://img687.imageshack.us/img687/7393/formulaspage.jpg The Attempt at a Solution This is the first time I see Vin connected to both the + and the -! I scanned my known...
  33. C

    Configuring op-amp to supply constant current

    Homework Statement How could an op-amp with feedback be configured so that it would supply a constant current to some load, even if the resistance of the load changed? Homework Equations None. Just a general question. The Attempt at a Solution I don't really know how to approach...
  34. Femme_physics

    Op-Amp basic problem with a LED diode

    Homework Statement http://img822.imageshack.us/img822/1859/theque.jpg Given the following circuit, including an Op-Amp and a LED diode. The voltage on the LED diode is 1.4 Volt. In your solution assume that the Op-Amp is idealHomework Equations (In the solution...) The Attempt at a Solution...
  35. B

    Op-Amp Precision Diode: Eliminating Voltage Drop

    [PLAIN]http://pokit.org/get/3deef3b185bf6b18007a25ddc18ce7d5.jpg So I have another thread running on op-amps, and while waiting for mr. Jiggy to come back online, I want to ask another op-amp question. This precision diode. I understand what is the point, and why it is so useful...
  36. Femme_physics

    Differentiating Op-Amp basic exercise

    Homework Statement Given here is an Operational Amplifier, its feeding Voltages are +-10. A) Calculate Vin to get a Vout of -2V, point out the direction of the current in this case (From a to b or b to a) http://img72.imageshack.us/img72/2550/needheed.jpg The Attempt at a Solution...
  37. B

    Op-Amp Input Voltage: Explained

    op-amp --- input voltage Hello, I find op-amps very fun! And I understood mostly everything I was offered to study. But here is the thing. Why does the voltage has to be the same at the input leads? To be more specific. Lets say we have a inverting op-amp. And we have an imput Vin at -ive...
  38. M

    Finding the output current in an op-amp.

    Homework Statement The problem is gives an ideal op-amp and wants me to find the output current of it. Here is a picture of the problem. http://i.imgur.com/NfO6q.png Homework Equations vp=vn in=ip=0 The Attempt at a Solution So what i did is take KCL at the Vn node...
  39. S

    Understanding Op-Amp Gain with Potentiometer Configuration

    Homework Statement Here's the network: R1=100 The gain ranges from -1V/V ---> -10V/V and the potentiometer R4=10. Is R4 and R3 in parallel with each other? I can't seem to get the right answer... Moreover, this is what was done: -(R2/R1)(1+(R4/R2)+(R4/R3))=-10 Can someone...
  40. O

    Op-Amp Current Analysis: Solving for Collector Currents with Base Resistors

    Find all Collector currents I don't even know where to start, I added base resistors but am still getting stuck how can I find current in the first transistor?
  41. R

    Understand Differential Gain & Bias Voltage of OP-amp & Transistor

    What is the meaning of differential gain? Iam studying a document that says, opamp can provide differential gain unlike transistor. I don,t know what does it mean. Can some clear me out. More, what is meant by bias volatge in case of op-amp. I am very beginer to electronics.
  42. R

    Understand Rail-to-Rail Output Swing & Multi-Channel Data Acquisition

    I am just reading an op-amp datasheet. In that, they have written in features as "RAIL-TO-RAIL OUTPUT SWING" and in Applications as "MULTI-CHANNEL DATA ACQUISITION". What does they mean? Can someone explain me in simple way.
  43. E

    Question with my circuit in multisim dealing with op-amp

    I am drawing a circuit but not getting right result. I am to assemble the circuit below using +-10V supplies with all those specifications I have put in. I leave Node A open and adjust R4 to make Vc=0V. When I measure Vc originally it is about 10VDC(on the DVM). If I use a 100M resistor it only...
  44. S

    Digital to analogue converter(DAC) using op-amp

    Hello experts! Here is 3-bit digital to analogue converter. I have a question related to this. 1)What does it mean if you have to say to perform operation on it with 101? 2)And we can obviously conclude and see output voltage on oscilloscope. But by calculation how can you predict...
  45. A

    Solving the Inverting Op-Amp Circuit Puzzle

    Here is the Problem. http://img577.imageshack.us/img577/3769/screenshot20110803at231.png Uploaded with ImageShack.us I know the first part where the signal goes from A to B and i know what the signal will look like at B, as i used the inverting op amp formula. Vo=Vin x -Rf/R1 I understand...
  46. C

    Amplifying Load Cell Output - What Am I Doing Wrong?

    So I have a load cell that outputs a + and - signal in the range of 0 to 30 mV depending on the force applied. I fed the +signal through a non-inverting amplifier that bumps up its value to about 4 V. However, when I applied force onto the load cell, the voltage range did not get amplified. The...
  47. J

    Is this op-amp configuration the solution for measuring haze at ambient?

    Im doing my thesis its about measure haze at ambient, so I found very little information about DIY schematics to work with photodiodes, at last my tutor found something, but when I was doing the circuit I found that this doesn't worked! well I made some mods and for a mistake I found a...
  48. J

    Basic Op-amp Integrator circuit question

    Hello All, Today, I was experimenting with a basic op-amp integrator circuit (I have a piezo element that I ripped from a buzzer, which I would like to use as a mechanical pressure sensor). So I'm using an integrator circuit to integrate the voltage signal produced by the piezo to get a...
  49. N

    What is the role of the feedback resistor in an op-amp circuit?

    I just started learning about Op-Amps. Working through basic equations seems straightforward, however I was curious about the function of the feedback resistor. As the name implies, one might infer the current/voltage potential "feeds back" from the output back into the input (I know there are...
  50. M

    Single supply op-amp configuration

    I'll try to make my description quick so you don't tldr me. So I worked on this project in school on a 6.5inch woofer. I took it from an old computer set (creative) and the amp was dead. I designed and built a new dual supply class ab stage amplifier with a low pass filter. So now I don't...
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