Opamp Definition and 152 Threads

OpAmp "Non-standard" Feedback Hello, This is my first post here. Please excuse my poor English and grammar. I will try to make my questions clear. As I understand, with a negative feedback, where the output connected to the inverting input and in the ideal case, the Vn and Vp will be...

An ideal opamp is said to have infinite gain and high input resistance. But why do the designers want to have infinite gain? This makes it impossible to use it as differential amplifier as even small voltages will have very large values. We have to add a negative feedback to use the opamp...

Homework Statement Homework Equations Can anyone help me how to find the current 3.6mA analytically? I have tried but I didn't get any right answer. Thanks

Homework Statement Design an Opamp circuit for which the output voltage will be of the following form Vout = 2v1 - 3v2 Check with Multisim Homework Equations The Attempt at a Solution We have only learned the basics of Opamps thus far, so I am confused with the...

Homework Statement I need to simulate an OpAmp in Simulink but I can't seem to find an OpAmp block that works in SimPowerSystems, so I kept searching and found out sort of an equivalent. However, the simulation still gives me an error. I would highly appreciate if anyone could tell me what I...

i have attached a bode plot and the opamp dc second order lpf circuit. the opamp Tl082 has a gain bandwidth product of 4Mhz according to the datasheet. this circuit has a bandwidth of 414.25khz. can we determine the opamp' individual gain-bandwidth product from this plot ?? if yes , how do we...

We all know the Differentiator and Integrator configurations of the Operational Amplifier. I realized that the RC circuits used as low pass and high pass filters can also be used as integrators and differentiators. Its obvious from their differential equations actually. As for current to...

Hello, A little while ago I built myself a passive mixer (some resistors, some switches and a bit of solder). Now I've decided to take this further and build a proper mixer using op-amps. So I have got myself some NE5532 opamps to use. I am trying to build a very simple test circuit...

Hey everyone, I am trying to solve for the circuit that I have attached. So I know that for a opamp, it does not draw any currents into its input side and the nodes b and c are the same potential. To figure out the potential at node b, i need to know I_6, but that 6k resistor is messing...

Homework Statement I am trying to figure out how this ckt works. But no idea, where to even begin. see attachment tp.png Homework Equations The Attempt at a Solution Q1 is diode connected. The Vbe temperature dependence is amplified to indicate the temperature. -2mV/ deg C Gain...

I am working with Pspice student verison 9.1. Is there any simply way i can find out the input and output resistance in pspice? basiclly my opamp is same as this without Rg resistor Thank you

Homework Statement Hi, I am trying to use pspice student to work out a ideal opamp. This is what i did: Homework Equations I have find out the gain for my opamp using simulation. But the problem is how can i find out the DC open loop gain using this software? i have google it and it just...

Hi, i am using Pspice schematics to build up an inverting opamp with 10 gain using an input sinusoidal source. For other opamp model, i will need to connect Vp and Vn to the top and bottom of opamp. But for this opamp (shown in the fig. below). Where should i connect my Vp and Vn? And how can i...

I'm trying to solve this problem and the first 2 questions on it are giving me a tough time. Picture Attached. (1) Determine the equivalent impedance Zeq of the OpAmp circuit. Assume that the OpAmp is ideal. (2) Determine Rx, Lx, and Ry as a function of R, R1, and C such that Zeq of the...

Hi gents. In a rig several times an OpAmp LM-324 burns and melts (and support too ! ). The circuit works perfectly for many hours and suddently ... I must precise that high voltage ( -6 kV) is not very far. My question : is ESD able not only to destroy OpAmp but also to make it melting ?

Hi, Just a general question. For an ideal opamp, does any current flow from its output terminal? What is the reasoning behind whatever the answer is? Thanks

can opamp work this way ?? can opamp work this way ..? when i input 2volts the output is 4volts , when i input 5 volts the output is 25 volts in simple words can opamp takes the square of input signals ?? is it possible ? i know how it work as differentiator, integrator, Summing amp...

I am trying to understand Type1, 2 and 3 opamp compensators used in DCDC converters. Type 1 is just an opamp integrator. Type 2 has a C in feedback loop with parallel RC. How does this boost the phase Margin? (page 307 - http://tinyurl.com/3qyt5dc) I understand phase and gain margin when...

Hey guys, first of all this is my first post in here so I hope I am doing the procedure of asking questions the right way. My problem is; I want to add two signals and generate a 1.5 period of sinusoidal wave only at the beginnig. It will be a sine wave starting at t=0 and ends at t=1.5T...

Ok, sorry for this basic question, I am currently designing a sallen-key high pass filter using a TL072 opAmp, with the schematic shown below, This circuit is connected to a piezo trasnducer whose signal I wnat to amplify. I was wondering, what do I connect to the Vcc+ and Vcc- pins of...

Homework Statement What is the gain of this Op-AMP. Express symbolically (Eg. in terms of R1, R2..) http://img195.imageshack.us/img195/3389/opampproblem.png Uploaded with ImageShack.us Homework Equations KVL/KCL The Attempt at a Solution i1=i2 Vx (the voltage at the...

I can't understand an opamp circuit whenever there is an active element in the feedback loop. For example, in the current monitor ckt(attached). I don't understand how it works. I can't figure out how the opamp offset and BJT gain would affect the output. This ckt is from national semi AN31.

Can anyone please give me the design of a high power opamp based amplifier, Vcc(100-200V, single power supply), Output current(tens of amperes)

In an inverting opamp let the output be feedback to inverting input through a feedback resistor Rf. We write the direction of flow of current from input terminal to output terminal in the feedback resistor Rf. But if this direction is correct then how can we say that input is fed back?? it seems...

ideally input current of an opamp is 0. If input current is zero then how is that the opamp can give an output? is it that in a real opamp a very small quantity of current flows?

I am also having an op-amp problem. I want a simple voltage gain through an op-amp with inputs ranging from 0-5V, which will then be fed through an integrator. I am using the LM358 op-amp. The datasheet and the diagram are attached. For some reason, though, I am getting a gain far exceeding...

In the datasheet it says the voltage max is +/-18V. Does this mean that the maximum on Vs+ is 18V, or that the maximum voltage between Vs+ and Vs- can be 18V, or 36V? I want to power it with Vs+ at 36V and Vs- at 0 volts.The datasheet is here: http://focus.ti.com/lit/ds/symlink/opa627.pdf

I have a fliter that uses OpAmp based integrator. I want to make the same filter but using OTA-C instead of opamps. But I'm confused on the process of doing that. Anyone can help me on how to get the same behavior from the transition from one to an other?In other words translating the RC values...

The first part of this problem was to find the gain using an ideal OpAmp. I am on the second half of this homework problem, where we find Vout/Vin, aka Gain, using a non ideal OpAmp. The attachment is the picture of the circuit. I know that since the OpAmp is no longer ideal A no longer...

I'm trying to build a circuit using a lm741 op amp, and normally the opamp requires +-15 V to run it. However currently I don't have a power supply that has a negative output. Correct me if I'm wrong but isn't connecting the device from +15 and -15 the same as just connecting a +30 to ground...

helllo i am having a problem designing this circuit i should use opamps resistors and switched i have a fixed 5v dc input i should get an outpout of -1 -2 -4 -8 -16 the user should choose which one he should use can i get some help please?

Homework Statement http://img3.imageshack.us/img3/3939/opamp.jpg Draw an imaginary boundary around the op-amp, and apply KCL at the five wires that intersect the boundary Homework Equations The Attempt at a Solution I am having quite a problem understanding the question...

So I was playing around with logarithmic & exponential amplifiers in my lab class. I was looking at the following equations: http://upload.wikimedia.org/math/7/7/6/77663157d5b97ceb2e3edac5f587a620.png and http://upload.wikimedia.org/math/b/3/c/b3c569c85552561e41dec916f6e8ebe8.png...

I used LM324N(4 opamps on 1 chip) from ON semiconductor to build an Instrumentation Amplifier circuit. I chose the values of the resistors so as to give a gain of 640. But when i checked the gain on the CRO the gain was around 175. What problem could this be? Datasheet...

Homework Statement Circuit: Both inputs are connected to a person's wrists (we tried it with fingers too). The resistors are both 1Mohm "What is the name of the resulting waveform?" The Attempt at a Solution All we saw is noise and something that looked like a triangle function...

hi friends, i cannot understand the derivasion of OPAMP as an integrator. my book has suddenly replaced a term 1/s(where s=jw ) by an integral with time as variable, without any explanation. another thing is that if OPAMP can act as integrator, then why is it not THE BEST...

Can PNP input opamps be replaced with NPN input ones? I want to replace the LM324N with something better.

what is the difference between opamp & differential amplifier?

I have what seems like a simple problem. I was asked to use a simple resistor divider as a scaling circuit into an A/D converter. My problem is that I have a low steady-state current requirement, and so I needed to increase the resistor values. I was told this is not an option because it...

Homework Statement If you were to generate a square wave with zero offset voltage using a function generater. What shape wave would the V out be if put through an opAmp?? The Attempt at a Solution For some reason this seems like an odd answer to me, because i want to say a sine...

i have problem in understanding the basics of op-amp let's consider an opamp as voltage follower (i.e) the output is connected to inverting terminal directly and if V1(say 3v) is applied as input voltage ,to the non-inverting terminal, the output gets saturated immediately +v-cc(power...

Homework Statement We're modelling a coax-cable. This is the first cable segment (/m): .. ----._.----./. ----dR1----dL-----------... ..|.........|...|... Vdc.......dR2...dC8... ..|.........|...|... ..-------------------------------------------GND ... Empty Space A short DC...

I have a few questions concerning opamps. First what is the big deal about infinite common mode rejection? It seems to me by looking at the open-loop gain equation A(V2 – V1) = V0 it is obvious that when V2 = V1 the output is zero (common mode rejection). This may be where I am confused …...

Hello Everyone, I am trying to model a circuit using Orcad Pspice 9.2 I am trying to solve the time when the opamp saturates with maximum voltage operation of 10v and -10v. I am applying different voltages to the circuit, when I do the transient analysis, i am not getting the right time. For...

Does someone know a good book or site or something about opamp's Thx guys

Problem I: Can someone help decribe what this circuit is meant to do ie. its basic operation? I am not quite sure what is going on. I have attached the input/output waves and the actual circuit diagram. The smaller signal (green) is the input (from the left) and the larger signal...

The professors have taught you that in an opamp, the voltage in one terminal is equal to another. Suppose you put a 5V voltage source in one terminal and 2V voltage source in the other. What happens then?

Homework Statement http://img440.imageshack.us/img440/9996/untitledbq0.png Homework Equations Please see picture. The Attempt at a Solution Please see picture. --- I have a strong feeling this is incorrect. I think I'm missing something important here... I don't know what...

Homework Statement There is a non-inverting op-amp below. http://img291.imageshack.us/img291/8242/chapter5lastproblemea1.jpg The op-amp is NOT ideal. We assume that R_i\,=\,\infty, R_0\,>\,0 and A is finite. Find the general Thevenin equivalent circuit seen at the terminals...

I was wondering,how does positive feedback works in opamp circuits?Like is there any formula for calculating positive feedback?I know that with negative feedback we have Vp=Vn but I don't know how it works with positive feedback!Thanks for the reply!