Op-amp Definition and 217 Threads

example of a varible capacitor input op-amp to voltage level circuit. I'm not sure how to turn reactance to a voltage level using an op-amp? :wink:

Homework Statement Okay, This time it's an exam question. I am doing some past papers and there are questions about comparators which are not introduced in this course (this course is preliminary course for engineering students who are interested in electrical, electronic or computer...

Hi everyone, I'm trying to implement the attached circuit. (the .txt is for http://www.falstad.com/circuit/) Since I only have a single power supply and I ultimately want to drive this with a battery I am powering the opamp with a virtual ground. Using a voltage divider to achieve this. Opamp...

Homework Statement I need to characterize the circuit below in order to compare measured data to theory. Can you determine any the theoretical relationships for the frequency, amplitude, gain of the two voltage outputs? I measured the output voltage of each op-amp while varying both of the...

Does current flow through the feedback resistor without going through the op-amp at all? After all, the op-amp is supposed to have very high input impedance right, so if the current just flows through the feedback resistor, wouldn't there be nothing going through the op-amp? Also, how does the...

I'm trying to build a circuit to solve the differential equation x''+2x'+x = f(t), where f(t) is a sine wave with frequency 5Hz and amplitude 0.5V. I am supposed to get a sine/cosine wave (as the diff. eq is just the same as the ove governing spring-mass forced oscillation) as solution, but...

I know how to derive the expression Vout = -CR*d(Vin)/dt for a circuit differentiator that consists of a capacitor and a resistor, how I can understand the attached circuit, which is part of practice exercise for my class. Why do we need to add R2 and R3? When I run the simulation Vout =...

Hi. I have moved on to the next question. There is something I am confused. The question wants us to express Rf in terms of R such that vo = -15vi. After doing the last task, I think I understand the flow of solving it. But here still exists a problem. My attempts and question are listed in...

Homework Statement Given the ideal op-amp, determine the resistor R2 and the current I2 where Vin=500mV, Vout = 2.5 V, and R1=5kV. Homework Equations No current passes through op-amps, the op-amp tries to make V+ and V- equal. Ohm's law, voltage divider equation The Attempt at a Solution...

In the following circuit, compute the values of R1 and R3 in terms of R2 and R4, such that vo is always equal to v1 - 5v2.I have marked 3 nodes, A, B and C. v+ = v- as assumption for the op-amp. Consider node A. v- = v+ = v1 × (R2 / (R1+R2)) Consider node B and C. (v- - v2) / R3 = (vo - v-) /...

Given this ideal op-amp, determine Vout if Vin = 2V and Vs = 15 V. So I know that the ideal op-amp has infinite gain. As the difference between V+ and V- is substantial (2V), wouldn't that mean the output would theoretically by infinitely large but instead max out at Vs? Am I understanding...

Hey all. I have a question regarding an equation in a document I am reading about convex optimization of OP-AMPs. The document is attached, the equation is of section 3.4 and the equation number is (9). Can you please explain how it came to be? I understand that i3 = i4 = i5/2 but I don't...

For the simplest case you have a feedback resistor and an input resistor. The non-inverting input is connected to ground. 1. If the gain is only dependent on the ratio of the resistors, is there some sort of advantage in picking higher valued resistors (in the k range) rather than 10 or 20...

It is possible to use a capacitor/inductor in an op-amp to allow it to perform the mathematical function of differentiating or integrating an input signal. It is also possible to do this without an op-amp, using simply resistors, inductors and/or capacitors. So what are the advantages of using...

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

Homework Statement For an input potential (Vin ) which is a 1V (peak) sinusoidal source. Calculate V1 and Vout Homework Equations - The laws for an op-amp - NVM The Attempt at a Solution Here is my attempt not sure if correct.

I am using (attempting to at least) a photodiode to count fringes from a Michelson interferometer. Here is the amplification circuit I am using: Coming out of the op-amp into the comparator I get about 4.2V in a well lit room, 2.17V in total darkness, and 2.33V when the brightest part of the...

Homework Statement Consider the circuit drawn below This diagram was the closest I could find online to the one equivalent to my question, but there are some adjustments I need to clarify. 1)Replace Rz, Rf, and Rin, to R1. 2)Also, in my question, there's an extra wire connecting Vout to the...

hi guys My op-amp theory is a bit weak ... I have gone to a dozen sites trying to identify the layout in the circuit below ( this was from some one in another forum asking Q's and I got to a point where I couldn't describe any further) he was first asking about the back to back zeners so told...

Homework Statement I have got transfer functions W(s) and Wk(s), where Wk(s) is correction transfer function. So I calculate W(s) and Wk(s) in series. Magnitude graph before correction: Magnitude graph after correction: The task is to make whole circuit and simulate it. Homework...

Hello, I am working on this previous final exam question. I am totally stumped with getting my answer with frequency. I believe my answer is correct with impedance, but I am having a hard time changing this to ω

Homework Statement http://puu.sh/8mUJ5.png here is the image the question is to find the A at Vo1 and Vo2 The attempt at a solution I don't know how to calculate A at Vo1 but at Vo2, what I need to do is just A= 1 + R/R is that right? At Vo1, what I think is only A= 4R/R but is...

Homework Statement Homework Equations Vp=Vn Ip=In=0 The Attempt at a Solution By voltage division: Vp = 8/(8+8) V3 Vp = 1/2V3 Vn = 1/2V3 By node-voltage method at the inverting input terminal: (Vn-V1)/4 + (Vn-V2)/4 + (Vn- V0)/8 = 0 Multiply equation by 8 2(Vn-V1) + 2(Vn-V2) + Vn-V0 = 0 V0 =...

So this is the circuit(with equations which were written by me, so I don’t know if they’re correct) and this is the graph I should get, but I don’t know how.( g(x) is the current vs resistance) I assume that those two equations collide somehow and I get that g(x), but I’m not sure. So my...

What is the work of the earthed line with zero potential between two power sources in the op-amp. What is the normal function of Earth wire except for preventing shock?

Homework Statement For vi(t) =V0 cosωt, obtain an expression for vout(t) in the circuit below and then evaluate it for V0 = 4 V, ω = 400 rad/s, R = 5 kΩ, and C = 2.5 μF. Homework Equations The Attempt at a Solution For this problem, I am having difficulty taking that second term...

Homework Statement Determine vo across the 10-kΩ resistor in the circuit below. Homework Equations The Attempt at a Solution For this problem, using the ideal op-amp model, I believe the currents are zero in both the positive and negative terminals of the op amp. Therefore, there...

Homework Statement http://i.imgur.com/TBrFMIT.png Homework Equations The Attempt at a Solution So I basically start with node voltages at the positive terminal of the op-amp, and I label that node E, so the node voltage goes: VE/80 + (VE - VD)/20 = 0 (I labelled the node at the...

Homework Statement Design an op-amp circuit that can perform the operation:Vo = 12VS1+3VS2, while simultaneously presenting an input resistance of 50 kΩ on the input side for source VS1 and an input resistance of 25 kΩ on the input side for source VS2. Homework Equations The Attempt...

Homework Statement Find Vo as a function of Vs Homework Equations The Attempt at a Solution My thought process so far is to do KCL and find Vo as a function of Vn2, then Vn2 as a function of Vo1, then Vo1 and Vo as a function of Vn1, then Vn1 as a function of Vs, finally giving me...

Homework Statement Problem #6 on the attachment Homework Equations The Attempt at a Solution I am stuck because if I do KCL at the node above the current source, It seems like all of the current should go back into Rs and none from the current source goes up to Rf

Homework Statement Problem statement is in the attachment HW 5, it is problem #1. Homework Equations The Attempt at a Solution I am just stuck with a whole bunch of variables and this just looks like a complete mess

Homework Statement I need to find an expression for the gain in this circuit. I know it is an interting amplifier, because with the models we were given to look at, this one fits the inverting amlpifier. I've also constructed a simulation in a simple Java applet that I have. My problem...

Hello, I have a question that I thought some of you may know an answer to. I was recently testing an op amp is several closed-loop feedback configurations. Primarily inverting, and non-inverting. When testing the output voltage of an invertin amplifier, I found that the output signal...

I am working on the prelab for my class right now, and I am having difficulties understanding how to get my Multisim to work. Sadly we have not learned about Op-Amps, and by design our instructor has us do problems involving things not taught in class in order to force us to do research and...

In the inverting operational amplifier circuit I've drawn below I am trying to calculate the output voltage and the voltage at the blue spot. The resistors are of the magnitude of several K ohm. I have done the following: Uout = Rf * (I1+I2+I3) = Rf * (U1/R1 + U2/R2 + U3/R3) The voltage Ux...

Homework Statement http://imagizer.imageshack.us/v2/800x600q90/690/0tab.png I'm asked to find the transfer function and then find the state space representation and seem to be stuck. Homework Equations The Attempt at a Solution My textbook states that for a noninverting...

This picture is from http://www.ecircuitcenter.com/Circuits/op_ibias/op_ibias.htm I am not very sure if I am getting the right idea of how the IB+ and IB- works, but when i solve it open up one of the IB to solve the problem. for IB+, (IB- is opened) Vout = V-( 1 + R2/R1), ... V- = IB+R3 Vout...

Homework Statement http://imgur.com/tJEPgbA http://imgur.com/tJEPgbA Homework Equations The Attempt at a Solution I started by focusing on the left Op-amp provided. My methodology to solve this question was essentially to assume a virtual short circuit so that the negative...

Problem in paint doc. I'm interested in why V- = 0. Is it always true that V- = 0? If not how was it decided that V- = 0 for this given probem?

Homework Statement Prelab material, I know how to solve for the gain and vout on a circuit. But reading the actual manual of a op-amp is confusing and I just want to make sure I'm correct. The initial input voltage will be a 1V triangle wave. Then later we increase the voltage to 3V. R1 is 1K...

Homework Statement Find the input resistances and voltage gains for those ideal op amps Homework Equations The Attempt at a Solution The original inverting circuit look like this : we already have the equations : input resistance = 10k voltage gain = -r2/r1 = -10 For the...

Homework Statement Determine the output level (maximum positive or maximum negative) for each comparator in Figure 4-52. Homework Equations A_{ol}=\frac{V_{out}}{V_{in}} The Attempt at a Solution I am new to comparators but I thought that since all of these op-amps are...

Homework Statement How will you measure a voltage of range 0.0001 volts using the 741 OP-AMP? Homework Equations The Attempt at a Solution This a viva question and i couldn't answer. I don't know how to begin. Should i use Sample and Hold circuit or something else?

Hi all, ME major here that's very confused about the integrating op-amp. It's pretty simple what I am confused about, just unit problems. Suppose you have the following integrating op-amp circuit: Feedback capacitor: 10μF Input Resistance: 10kΩ Input Voltage: 5V[sin(100t)] My...

Homework Statement Problem number 6a in the picture. Homework Equations Transistor: Ic = βIb Ic = αIe Ic = Is*e^(Vbe/nVt) OP-Amp: Vo = Acl*Vi Acl = 1 + (Rf/Ri) The Attempt at a Solution I tried to solve but just couldn't understand the behavior the transistor.

Homework Statement In a system to regulate speed, a speed gauge is connected to the following circuit What's the purpose of this circuit? What's the difference between Uout and U*out? The Attempt at a Solution I assume that the purpose of this circuit is to help prevent...

Homework Statement Design an op-amp based circuit to produce the function Vout = 5*V1 - 4*V2 Homework Equations The Attempt at a Solution I have no idea how to approach this. I know there are two voltages on the two inputs, and that the feedback resistors should be going to the...

Hi everyone, how should I manage to make the analysis of an op-amp when there is something between Vn and Vp,, for example my teacher gave me an exercise where between Vp and Vn there is a Current generator, how should such op-amp circuit should be treated, and how do you think and reason when...

Normally the connection of supply voltage is +-V but now is +V and ground. What happen if Op-amp (ua741) with only positive supply voltage? The op-amp still function?