Op amp Definition and 307 Threads

Homework Statement (See attached figure) I need to find V0 in terms of R1, R2, R3 and C.Homework Equations V0 = -RC (dVs/dt) for a differentiatorThe Attempt at a Solution I understand I have to apply KCL at the node between C and R1, and I've also determined that R1 and R2 are in series (not...

please help me i need a replacement for lm1013 IC please does anybody have an idea ?

hi everyone , i solved a textbook question which says : http://img268.imageshack.us/img268/8994/img1379sa.jpg http://img685.imageshack.us/img685/3228/img1380z.jpg and found analytically : ia = -470 uA, ib = 770 uA , ic = 22 uA, ig= 322 uA, is = 64.5 uA Ra= 1kohms, Rb=2kohms, Rc...

Hi this is my first subject in this forum and i hope you can help 1.we have been given an assignment to analyze this non-ideal op amp with both positive and negative feedback and to be honest i don't even know where to start i know i should post an attempt of trying to solve but honestly...

Hello, I was trying to derive the transfer function of a simple inverting op amp topology, incorporating the output impedance, Ro, of the non-ideal op amp, to see how it, when combined with a load capacitance can induce oscillations (or at least ringing). I haven't been able to get a valid...

To start I have attached an image of the circuit. We are to relate the V_{0}to V_{s}. I am not exactly sure where to start with it. I know that V_{-} and the V_{+} on the op amp have to have the same voltage. The resistor that bridges the two inputs is throwing me off. Not sure if this is the...

Homework Statement http://www.freeimagehosting.net/jqqoz Homework Equations V(output) = V(input)(R2/R1) The Attempt at a Solution The equation above is valid if the back part of the upper circuit (involving R3,R4 and the Earth wire) does not exist. I tried to improvise with it by...

Design a noninverting voltage amplifier which can be varied between 1 and 100 capable of driving a 10 K load to +5V at a frequency of 1KHz. Also how do i design same thing with inverting. Can any1 help me schemetic with multisim or pspice. also make me understand how we should...

Homework Statement Design an op-amp-based integrator with the dc gain equal to -10 V/V (use R1 = 200 Ω and R2 = 2 kΩ). Knowing the gain-bandwidth product of the μA741 op amp, find the proper value of a capacitance C of the integrator so that its 3dB frequency is 50 kHz. Homework Equations...

I have tested this circuit on the computer and it works but when I try to make it both on a pcb and breadboard the circuit will not work at all. If i swap the thyristor - TIC106D - for a transistor - TIP121 - the circuit works fine so I think the problem can be isolated down to somewhere between...

Somewhat unusual question: Do you think LMP7721MA would get degraded by xrays used for luggage screening? It is an electrometer opamp with extremely low input bias current: http://www.national.com/pf/LM/LMP7721.html#Overview Normally the electronics is not affected by the xrays but this...

Homework Statement A thermistor T is included in the circuit shown. Calculate the resistance of resistor R such that the output of the op-amp will change polarity at 6oC if at that temperature the thermistor has resistance 3 kΩ Homework Equations The Attempt at a Solution The...

http://pokit.org/get/8119a4b8a37171c67971c3fb13b33063.jpg Consider picture above. I understand how an integrator behaves when the capacitor is full. It(capacitor) acts as infinite resistance ergo open loop so we get positive saturation at the output. What I don't understand how come we are...

Help me ! I have designed a multi op amp circuit, and am now looking to build it. will i find any practical issues with such things as external interference, resistor tolerance, op amp imprfections, bandwidth issues, internal resistance. If so why?

Homework Statement I have to find the transfer function of a linearly and ideally operating OP Amp. http://i.imgur.com/u3f6E.jpg Homework Equations The Attempt at a Solution I know that the current through the capacitor, R1, and R2 is the same, so i=C(dv/dt) = Vin/R1 =...

1) What is a typical voltage level coming from an 8Ω speaker being used as a microphone to record a human voice at average volume? I kept forgetting to bring it to school to measure it's output with the oscilloscope, so I'm wondering if anyone here knows it. 2) I seem to remember reading...

Homework Statement A certain op amp has the maximum offset voltage magnitude of Vos = 2 mV, the maximum bias current of Ib = 100 nA and the maximum offset current magnitude of Ios = 10 nA. The op amp is used in the noninverting amplifier shown in the diagram below. Find the worst-case DC...

Homework Statement A certain op amp has a maximum output voltage range of ±9 V. The maximum output current magnitude is 20 mA. The slew-rate limit is SR = 300 kV/s. The op amp is used in the amplifier circuit, shown in the diagram below. For a frequency of 10 kHz and RL = 2.2 kΩ, what peak...

I am trying to understand how some of the standard ICs work in terms of simple components I understand, i.e. transistors, resistors, capacitors, and inductors (although I doubt there are any inductors in an IC.) I was trying to build and op amp from transistors, resistors, etc, and I noticed...

Quick question: how do you solve an ideal op amp circuit with the two terminals connected to independant power sources?

Hey guys we're learning about op operational amps and I'm having a struggle on how to transform any given circuit with an amp into its equivilant. i understand all the math involved once the equiviliant has been found, just getting to that point is a bit confusing for me. An example i found...

hello, I have a strange problem! I wanted to amplify my signal and i used 2op amps, each of them has a feedback resistor between (-) pin and output( pin 2 and 6 in 741) the ratio of resistors(r2/r1) is 150, but my signal only amplify 5times! I change the R2 resistor but nothing changed! i put...

hello, Is there a limit for the numbers of op amp we use to amplify a signal?! I mean is there a problem if I use 3 or more op amp to amplify a signal?!

Hello. I have a very quick op amp question. I'm trying to understand an omp amp. My question is will vout of an op amp go to zero if the inverting input is greater than the non inverting input ( even if there's a negative/positive feedback)?

I need help calculating the R values for this circuit from the following article: AN HIGH RESOLUTION RESISTIVE PROBE FOR NONLINEAR ANALYSIS OF TWO-PHASE FLOWS L. Cantelli, A. Fichera, A. Pagano This is only a section of the circuit, there is more but I'm only interested in this part of...

Hi, I was wondering what the disadvantage of using a non-inverting summer was rather than using an inverting summer. I was told that inverting summers are better, but not why they are. I ask because I'm making a circuit that performs a center of mass calculation: (V1 + V2) - (V3 + V4) =...

current gain of an op amp? Homework Statement need to convert current(output of a detector) in the range of pico amps to voltage between 1-5V Homework Equations (to connect to an adc) The Attempt at a Solution I've connected an op amp(for current...

Homework Statement i have this circuit http://screencast.com/t/6rgXUvZW but I am not sure if i have set it up correctly, firstly is where I've put the multimeter V out? I am not quite sure and are the Vins supposed to be in AC or DC? and are they supposed to be connected to ground like i...

Homework Statement Find the output voltage Vo in the following circuit Homework Equations V = IR The Attempt at a Solution Hey everyone, this question has me stumped. The answer to the question is -IR_2 but I'm interested as to how this answer comes about. I'm not particularly amazing at...

Homework Statement 1. Using the LM324 op amp build an inverting amplifier with a gain of 50. Measure the cut-off frequency 2. Plot your results on a graph as a function of log(frequency). Comment on the results I have done this in a lab and then graphed it, it seems to be around...

Greetings Physics Forums, I'm reading up on Radio Circuits and studying for my General's Amateur Radio License and was learning about AM Demodulators. I understand that in AM you can use a peak detector to get the modulated audio out however in SSB radio don't you have to double the...

Hi there, does anyone have experience with amplifiers in cryostats? I would like to have one close to the sample inside the cryostat. The problem is that there will be at least 4T of field with large gradients and I guess that I have to insulate it. The sample is at 15Kelvin but I am thinking...

Homework Statement The problem is within a lab, so I guess I need to give some background first. Pretty much, I'm starting with the circuit shown here. http://imgup.com/image-EC69_4D91309A.jpg For the part of the lab I'm interested in, the values of R1 and Rf were put as 1 kohms and 10...

Homework Statement Homework Equations KCL & KVL. The Attempt at a Solution Using KVL: -9 + 10kI1 + 6 = 0 -10 + 20kI2 + 6 = 0 12 + 30kI3 + 6 = 0 40kI4 + 6 = 0 :. I1 = 0.3mA I2 = 0.2mA I3 = -0.6mA I4 = -0.15mA Now here's where the problem is. When I take KCL at the...

Hi! I solder the following circuit: http://en.wikipedia.org/wiki/File:Op-Amp_Non-Inverting_Amplifier.svg With an opamp of +-5V or 0-10V operation I use a 12V dc supply and give a Vin of 0.05V with resistors 10k and 1k. For all cases no matter what I supply I get Vout = Vsupply...

Homework Statement Hello everyone. I tried solving this ideal op amp for V0 but kept becoming confused because of the structure at the bottom. I only have experience solving ideal op amp questions when they are grounded and have not encountered one like this before. All the data is...

Homework Statement An original picture can be seen http://images3a.snapfish.com/232323232%7Ffp733%3A%3A%3Enu%3D52%3A%3A%3E379%3E256%3EWSNRCG%3D335%3B%3B7%3A542347nu0mrj". Homework Equations The Attempt at a Solution I am not really sure how to start, how would I find out what...

Homework Statement A picture of the original problem can be seen http://images3a.snapfish.com/232323232%7Ffp733%3C2%3Enu%3D52%3A%3A%3E379%3E256%3EWSNRCG%3D335%3B%3B84268347nu0mrj" along with some extra labels. Homework Equations superposition The Attempt at a Solution So I tried...

Homework Statement Find Vo(s)/Vi(s) for the OPAMP circuit in the attachementsHomework Equations V = iR, Kirchoff current law. 1/sC = Laplace transform of capacitor impedance. The Attempt at a Solution Make the voltage at the node = v'. ir1 = (vi - v')/r1 ir2 = v'/r2 iz = (v'-vo)/z z =...

Is op amp or any amplifier circuit/device a over-unity efficient device? The above question has been stuck in my mind, and I can't figure it out, as Vout is greater than Vin which Pin>Pout. So is it? I heard a lot about free energy and aether, thus come to this question.

Inverting amplifer question http://img210.imageshack.us/i/electronicsquestionsq30.jpg/ Can do part a) ! Vout/ Vin = -R2 / R1 and found part d) in a book, that closed loop gain is less but more linear and am able to draw the graph. Any help with b) c) e) f) would be great, particulary...

I am trying to drive a NPN transistor with a LM324 op amp. The darn transistor does not turn on when driven by an op amp. This is basically a current limit circuit. Instead of using a large value sense resistor, I used a small resistor(0.1 ohm) and used an op amp to sense and increase the...

Hello Am reading about amplifiers, and the articles i read suggests that for a successfull amplification the op amp should have an input impedance and zero output impedance. I want some explanation about this information, why the input and output impedance are important factors?

Homework Statement I have a question which asks for the weighting factors associated with several input voltages to an op amp. What is meant by this? This terminology isn't used anywhere in the text.

This is a very silly question. I can't believe I have forgotten. I have a 30v bench power supply and I am looking to test an op-amp running at +/- 15v. I have a supply which has a negative output/ positive output and inbetween a green common/earth output. How do I wire them to produce the +/-...

What is the output of the op amp when either Vcc or Vee is not connected. I simulated this and got Vsat. +Vsat when Vee was missing and -Vsat when Vcc was missing. But I don't know why the output saturates to +Vsat, even in a inverting configuration. Shouldn't it go to ground, since the...

In a pirani vacuum gauge the pressure is determined by the rate at which heat is conducted away from a resistance wire by gas moleculs. The heat is supplied using a constant current source and the rate of heat dissipation determined by the temperature induced change in the resistance of the...

In a pirani vacuum gauge the pressure is determined by the rate at which heat is conducted away from a resistance wire by gas moleculs. The heat is supplied using a constant current source and the rate of heat dissipation determined by the temperature induced change in the resistance of the...

Homework Statement Design a simple Op Amp circuit to find the position as a function of time of a falling body Homework Equations y=y_0+1/2gt^2 Assume y_0 = 0 at t=0 The Attempt at a Solution I used an integrator Op Amp with a triangle wave input. I chose the values of the...

Homework Statement Hi. Just like the title says, why is the output impedance of an op-amp so small? (as in physically, I understand why a low output impedance is a desirable characteristic)