Op amp Definition and 307 Threads

Homework Statement I recently completed a lab where I set up a buffer amp. Its input was a function generator set at 5Vp amplitude and we placed various load resistors on the output to test Vout on an oscilloscope ( 75kΩ, 3300Ω, 510Ω and 68Ω.) From my data I noticed that the Vout was the same...

Q1. Why do we connect the Diode 2 in the Op Amp- Relay Circuits? (Check the image ) Q2. Why shouldn't a high current pass through an Op Amp? Q3. Why should there be a resistor in between an LED and an Op Amp output?

What's the feedback for an op amp? And tell me the formula.

Homework Statement Solving for this circuit here, where V = -5V Homework Equations The Attempt at a Solution I found the equation for a summing op amp like this one, plugged everything in and ended up with -3V, which is marked wrong. I'm really at my wit's end here and the homework has been...

Hello there, this isn't necessarily a homework question. I came across this qn during revision and didn't know how to solve it. Any help would be greatyly appreciated. The answer is 0.97 1. Homework Statement For the ideal OP-Amp in negative feedback configuration shown in Figure Q30...

Homework Statement I need to find the gain. Homework EquationsThe Attempt at a Solution I know gain will be Vo/Vs. I originally tried to write different equations for each node, but I ended up with 5 eqns and 5 unknowns, and in the end it gave that vs=0V. Can someone give me an idea of what...

Homework Statement I am wondering if in this circuit Vb will be 0V? Homework EquationsThe Attempt at a Solution I have found all the other ones, but I am unsure if Vb will be 0 or not, and if it is then what is the logic behind it?

Homework Statement Determine the Op amp gain of the following circuit. V1 = 1v Vo = 4 V Homework Equations A = Vo/ VI The Attempt at a Solution Using voltage division I determined the voltage for the node at the +ve terminal VI = V1(1k/ ([1000 + 1]k)) = 1/1001 V Vo = 4v Given Therefore...

According to my professor's model answer for an assignment, when we derive the transfer function of an op amp circuit, we have a "K" value, which is the open loop gain of the op amp (I am not 100% certain), multiplied to the op amp circuit (1+R1/R2 for non-inverting amplifier for example). I...

I have tried many times testing some Op Amp LED flashing circuits on a breadboard from the internet. So far, none of them works. The photo above is one of my attempt using a Ti IC chip LM358. I have double checked my wiring and swap the 100k with 10k and 56k resistors. what is the problem...

Homework Statement An internally compensated op amp has a DC open-loop gain of 1,000,000 (V/V) and an ac open-loop gain of 40dB at 10kHz. Provide the expected gain in dB at 1kHz... Homework Equations Please help, I don't know what to use for an exact answer. The Attempt at a Solution Beyond...

Hi everyone. I am tasked with amplifying an input voltage of around 1nA at anywhere between 10,000kHz to 1MHz to a sufficient amount. We've been using op-amps in multiple stages in series to amplify the signal. At our disposal we have a function generator, oscilloscope, breadboard and...

Hello everyone, In my lab class we've been given task of using op-amps to amplify a current of 1nA and frequency of order of madnitude 1MHz to a discernable level. We've been given breadboards, a selection of different op amps, resistors, an oscilloscope etc to achieve this task. We've made...

Homework Statement Homework Equations V=IR KCL/KVLThe Attempt at a Solution I have a similair problem to this one in my notes and I know how to solve this circuit, but I am confused on some parts of it. First, at V1 why can we say the voltage there is 0V? Is it because it is connected to...

i connected pin 4 and 8 to gnd and +5 v respectively .when pin 2 touches wood, or hand pin 1 is high. i understand skin is capacitive , but wood?

Greetings, I'd like to invert a signal I get from a photodetector (the signals are up to 100 mV). I decided to use an inverting op amp circuit for that, however, when looking online through the op amp catalogs - the minimum input voltage in the descriptions is a few volts while my input would...

Hello I am developing a low noise preamp and would like to change the roll off of my design to sharply decrease the gain for very low frequencies "1-5Hz". The results of my current design are as follows. I would need something that looked more like this.. I understand the simple equations...

I want to use a differential amplifier to separate the digital and analog ground portions of a circuit, but am not confident in my understanding of the datasheet of the amps I have on hand (amp03). http://www.analog.com/media/en/technical-documentation/data-sheets/AMP03.pdf I think that...

The output voltage of op amp is greater than the power supply voltage (+/- 5V). Is Op amp burned out?

Could anyone verify if this is an impossible circuit, I put it in pSpice and it didn't work, I have no op-amps or voltage generators to build the circuit otherwise I would have built it. What do you all think, is it possible to find the transfer function of the far right op-amp? The schematic is...

Currently working through a chapter on op amp circuits, fundamentals. Came upon this practice problem in the section on inverting op amps imgur link: http://i.imgur.com/2DrQLXk.png imgur link: http://i.imgur.com/7KRKzKC.png A working of this problem is not given. I got the correct answer...

hi, i reallyt need help in this question. i tried this but i am not sure how to start this, so if you can provide me little help i will really appreciate it its based on OP AMP circuit thanks guys

Homework Statement [/B] Hello, I have attached the problem below. I am trying to find the value for v1 - v2 and iA. The given values are V, RA, and R for the other resistors. There are no numbers. Homework Equations It is given that the op amp is ideal, therefore v- = v+, and i- = i+ = 0 for...

Homework Statement Hello, I just came across a design problem based on an inverting op amp. The requirement output values are -25G and not greater than 1kOhm output impedance. With inputs 1V p-t-p and 75Ohms input impedance Choosing values for the gain seem fairly easy, but how these values...

Homework Statement Simplify in order to find voltage output. Homework Equations Vout= -Vref x (A + B/2 + C/4 + D/8) The Attempt at a Solution Firstly is this even correct? Secondly, I have 2 voltages (2.5V and 5V), what should I do now? what is my Vref?

Hey guys, need help with a problem here. Sorry for the quality of the image. I understand that above the op-amp, is the active low pass filter. So if I were to figure that out with respect to V2 and Vout, it would just be Vout/Vs = -(Zf/Zs) where Zf = (Rf/(1+jwCfRf)) Zs = Rs But I...

< Mentor Note -- thread moved to HH from the technical engineering forums, so no HH Template is shown > Hi, I'm working on a lab project and I have limited instruments/electronics. I am trying to use this op amp to amplify a few uA pulse to a 5 mA pulse. The pulse is passing through a...

Hi everyone, I am trying to make a Summing Amlifier. I have simulated on computer where it is working correctly, but on real circuit it is showing some mal functioning. I am using OP 27 Op Apmp. The circuit diagram is attached. When I try to add DC voltage to AC sine wave, initially sine wave...

Hello. I really don't get a concept of a way to generates negative voltage as a one of the supply voltage to typical OP-AMP. (Operational Amplifier) The output voltages is supposed to swing to more than 10 V thus supply voltages to OP-AMP should be +15V and -15V. I'm thinking of supply these...

Hello. Please see the attached image first. 1. The textbook seems say resistor to + input in this image is necessary to provide a return path to ground. I completely don't understand even what it mean. Could you help me to clarify this? 2. Instead of understanding directly what the book said...

[ mod note: thread title corrected ] Hi All, My first post in the forums, hopefully I'll be able to give out as much help as I receive. I'm currently stuck on an Op Amp gain derivation. Attached is the question and diagram, the derivation I am struggling with is part B. I understand the...

Homework Statement Write output voltage in terms of input voltages for the circuit drawn. I drew the circuit and then feed back loop. Homework Equations Ohms Law V=IR Basic Properties of Op Amps (ideal), voltages are assumed equal at both inputs... The Attempt at a Solution The...

Hi everybody I'm a newbie and working on LM324 to learn Op-Amp. this is my circuit: http://img4.uplood.fr/free/qx3o_20150425_172843.jpg One of the resistors is 217ohm and another 978ohm. then the gain should be 4.50691 as you can see. so far so good. I know this is for ideal Op-Amp. I applied...

Hi all, I realize I'm asking for the world here, but google hasn't been very helpful. I've found a few candidates with some/most of what I need, but wondering if there is some holy grail op amp out there that everyone is using. I'm growing tired of making work-arounds for the LM324's I have...

Hello, Like the title said, how can you tell if it's an inverting or non-inverting op amp just by looking the the schematic like this one. textbook said this is an inverting op amp. I thought whichever input node (+/-) the signal go through dictate the classification of an op amp if it's...

Is it possible to model memristance using op-amps? I searched google but found nothing.

Homework Statement An inverting amplifier with the DC gain of -9 (V/V) is built with an op amp having its DC gain of 105 and corner frequency of 30 rad/s. ▪ Determine the 3-dB frequency of the inverting amplifier. ▪ Sketch the magnitude Bode plot of the voltage transfer function of the...

Homework Statement Hi Guys, I am trying to solve this question, please look at the attached picture Homework Equations The general equation for a inverting amp is -Rf/R1 * Vin = Vout The Attempt at a Solution Well as the question says the two resistors, R2 and R must be treated as parallel...

Can Op Amps replace transistors? Can they do everything a transistor does? They can be used as comparators and amplifiers. Will they become obsolete.

Homework Statement The op am in the circuit shown is ideal. Calculate the following. a) Ia b) Va c) Vo d) Io Homework Equations I have found three equations one at Vn, Va, and Vo. The Attempt at a Solution The attempt solution is on the attachment. I currently have three equations with four...

Homework Statement Find Vin/Vout Homework Equations Vout = Rf/R1(Vb-Va) ? The Attempt at a Solution I think the answer is the first one. Answer choices: Vin/Vout = -2, Rin = 100 Vin/Vout = -2, Rin = 200 Vin/Vout = -2.5, Rin = 100 Vin/Vout = -2.5, Rin = 200 Vin/Vout = -3, Rin = 100...

Homework Statement Find V0 and i0 of the circuit. Homework Equations KCL The Attempt at a Solution I tried multiple times and never got the right answer. -------------- Hello, I am having trouble solving a problem. I will link a picture of the problem with answers, but it just seems I can't...

Homework Statement I have used words here I'm not sure will explain what I mean accurately. If you're confused, ask, and I'll provide as much context as I can. Given the below circuit a) What are the three properties of an ideal op amp? These properties provides background for two...

Getting confused on understanding how opamp works with zener in Feedback loop. Referring to the ckt here (attached.) (replace diode with 5V zener) Using virtual short, when the input voltage is zero, opamp output is 5V? Basically the opamp sources current into the zener. When the input is -1V...

For the above op amp circuit: Vin= squarewave with 10Vpp and 1kHz. C=0.01uF. Vcc and -Vcc is 15V and -15V. Using the above specs, I calculate R using these equations: Requirement: Create a triangle wave with output voltage Vo to be 10Vpp. This is a gain of 1. Using the above, I find...

Homework Statement Homework Equations The Attempt at a Solution Here is my attempt: http://i.imgur.com/oKjwI8O.png The problem is at the end, I get 0=0. What did I do wrong?

it is my understanding that the input referred noise current (density) can be obtained from Ibias via inoise=sqrt(2*q*Ibias), where q=1.6e-19. on op-amp datasheets, both Ibias and the input referred noise current are both specified. Yet, the value typically shown for the noise current...

The type of op amp I am using is Voltage-to-Current Amp. Under DC voltage input, it works perfectly well, boosting the current of a signal generator (DC mode) up to 250mA with the help of single supply working at 25V. However, when I turn the signal generator in AC mode, hoping to achieve...

I need to run a signal through a configuration so that it has a gain of 1/2. I'm trying to figure out what the best way to minimize the noise for a low frequency input. So far I've only really thought of 3 ways to do this: 1. Voltage divider into a voltage follower 2. Measure the input so...

I have to find both of the voltage ratios. This is just ugly algebra. Here is what I came up with, and was wondering if I was correct. Thanks