Amp Definition and 377 Threads

  1. D

    Help with understanding of RF theory-Kinetic inductance parametric amp

    So this might be long question that requires some literature review but I will try condense it as much as possible such that hopefully I can get some help without the reader having to review the related paper. So I will start off by saying that I am involved in a honours thesis in which I need...
  2. U

    How to Calculate the Complex Op Amp in Circuit Diagram

    TL;DR Summary: How to calculate the operational amplifiers in the circuit diagram Hello Everyone, I am trying to learn the circuit diagram of one of a device in which I will be doing modifications as a part of my Masters's Research to make it performance better. My background is in Mechanical...
  3. PhysicsTest

    Optimizing an Op Amp Current Sense Circuit: Are the Calculations Correct?

    TL;DR Summary: Trying to solve the op amp current sense circuit as per the schematic. I want to solve the below current sense op amp circuit, Are the calculations correct? As of now i modified the circuit by removing the capacitors, i will add them once the above circuit calculations are...
  4. cnh1995

    Engineering Differential amplifier confusion (BJTs + Operational Amp)

    Here is the circuit diagram provided in the book. In the solution, the book has used the following approach (red markings in the image): Input to the left transistor is 2V. Considering base-emitter junction drop to be 0.7V, the emitters are at 1.3V (left red arrow). Now, using the "virtual...
  5. A

    Engineering Why are the voltages calculated in this way? (CE BJT Amp circuit)

    Hello! I am having trouble with this emitter circuit. I am given U0 as well as all of the resistor values and I need to calculate the following. ## I_c## ##U_{CE} ## ## U_{C} ## ## U_{a} ## ##U_{Ca}## ##U _{Re} ## Now important to note that all of these need to be calculated at the working...
  6. R

    "Ground" and "Center Tapped" Power Transformer Secondary in guitar amp

    Hello - thank you for reading this, and thank you in advance to anyone who replies and clarifies the mystery of "ground." I have finally gained a full understanding of how a full-wave rectifier, two-power tube electric guitar amplifier works in a push-pull manner, but one thing remains after I...
  7. altruan23

    Engineering Op amp circuit -- Did I calculate the output voltage correctly?

    can someone check, if i calculated the output voltage correct? i used virtual ground because V+-input of the op amp is 0 --> V- input is then also 0.
  8. A

    Inverting op amp frequency response Bode plot help

    Using analog discovery 2 kit and the bode plot produced by the network analyzer is off. The scope looks fine and everything is behaving how it should except for the bode plot. The magnitude of the bode plot will start at the correct dB then right before tapering off it shoots up a few dB and...
  9. karush

    MHB -7.8.1 Amp, Period, PS, VS of 3cos(\pi x-2)+5

    Find amplitude, period, PS, VS. graph 2 periods of $y=3\cos(\pi x-2)+5$ ok I think these are the plug ins we use $Y=A\cos\left[\omega\left(x-\dfrac{x \phi}{\omega} \right)\right]+B $ or $A\cos\left(\omega x-\phi\right)+B$ A=amplitude B=VS or veritical shift $T = \dfrac{2\pi}{\omega-\phi}$...
  10. E

    This op amp does not have gain?

    Had this as a question from a class mate. This op amp should not have any gain in the DC or AC circuit. The coupling cap blocks DC and has no reference to get gain, while the AC needs a cap in the feedback loop to get gain. Is that correct? Oh, this is supposed to be in the inverting configuration.
  11. hugo_faurand

    Amplifier for piezoelectric sensor, OP Amp circuit

    Hello everyone ! I'm working with a piezoelectric cell and I need to retrieve the variation of the charge of the cell as a voltage signal. I found this circuit (a charge amplifier) with an OP Amp ( here the piezo cell is represented as the current source with the capacitor and the resistor on...
  12. M

    Noninverting op amp doesn't work on a highly resistive load

    Hi, I am using an Apex PA443DF operational amplifier to drive a sinusoidal signal at 100 V amplitude across a very large resistor with resistance of about 5000 Mega ohms. The amplifiers are set up as noninverting with a gain of 22 and function very well for small resistive loads. The sinusoids...
  13. AlexCaledin

    "Class-B" Audio Power Amp with "Current Pumping"

    Hello everyone, I was thinking how to cancel the class B crossover distortion, may I suggest to discuss an interesting variant. Let's start from this: - there is crossover distortion (and no current protection). The signal source is "full voltage, zero current". Let's make it "full current...
  14. wolram

    My amplifier -- why did this capacitor blow in my guitar amp?

    I have built several guitar amps, but the last one I built burned out a capacitor, can anyone think of a reson for this? it was an eloctolytic, all is working fine now I replaced it.
  15. Boltzman Oscillation

    Engineering Op Amp Books: Gain, Feedback & Examples

    I was wanting to get a book on Op Amps. Ideally it would have lots of examples but I also need it to explain gain, feedback, and all that important material in an understandable manner.
  16. bjAndrea

    B Converting 10 PSI to Electrical Energy

    This is not my subject, but I need to know if I can convert 10 PSI to energy. for example, If I have a permanent magnet motor rotate X time (RPM) to produce 10 PSI. Now Can I invert this process, if I have 10 PSI and let it pass on a permanent magnet motor, How much electricity will produce? in...
  17. D

    Confusion on: High Pass Filter at Op Amp Input

    Hello, I am simulating the input impedance of a high-pass filter with the output voltage of the filter input to the non-inverting pin of an op amp. I'm confused as to why the input impedance can possibly dip below the resistance of the high-pass filter resistor. Please see the following circuit...
  18. J

    400 volt 3 phase 16 amp machine -- can it be used in the US?

    Maybe you can please give advice. I have a coffee roaster here in New Zealand I would like to bring to the US. It is 400 volt 3 phase 16 amp. It has a blower, a heater and computer components to run it. It is like a very large popcorn machine. Can this work in the US?
  19. D

    I have an op amp that does not tolerate signals below ground

    I have a lm224 operational amplifier that does not tolerate signals below ground. What operational amplifier tolerates signals below ground?
  20. runningman19

    Design of an Op Amp Circuit for Voltage Amplification

    Hi Everyone, I would like to measure voltage output from a sensor via an Arduino. The sensor outputs 20 mV at max capacity. I'd like to bump this up to around 5 volts so it is easier to measure. My plan was to use a non-inverting topology coupled with an LM393N op-amp. The schematic for a...
  21. bobg123

    Engineering Circuit input impedance with ground in an OP Amp circuit

    I've been given the following circuit and have been asked to find the input impedance and the impedance between the input terminal and ground. I've never encountered an operational amplifier configured like this. I know that the voltages at the - and + terminals of the op amp are ideally equal...
  22. W

    Charging a battery and monitoring the current w/ an instrumentation amp

    Homework Statement Homework Equations CMRR = Av/Acm Acm= Δ/R , Δ = (2 x Tolerance of Resistor).R The Attempt at a Solution I have to admit I am a bit confused by the premise of the problem. My understanding is Vout is used to vary Vcharge in some way, so that Icharge is always 1.3 A. Then...
  23. E

    Op Amp Vout Calculation for Non-Inverting Configuration

    Homework Statement Solve for Vout Homework Equations Vout=Vin(1+Rf/R) The Attempt at a Solution I get it is a non-inverting op amp but there is no resistor from the non-inverting terminal to the output. I have no idea how the equation would be. I understand that noninverting is...
  24. E

    How to solve for Vout of this op amp

    How would you solve for Vout? I get it is a non-inverting op amp but there is no resistor from the noninverting terminal to the output.
  25. Abdullah Almosalami

    What happens when you flip the inputs of an op amp?

    So, from my textbook, and what seems to be standard, an inverting amplifier circuit goes something like this: However, when I switch the terminals of the op amp and follow through with the equations, I get the same Vout. So my question then is what is the difference? I know there is other...
  26. J

    Using 6 Diodes for a 30 Amp Battery Charger

    I was told once that two 1 amp tv type diodes parallel will not work because one will always carry the load, but I am working on a car 30 amp battery charger and it has 6 diodes 1/2" press in type all parallel same as from a 10DN series Delco alternator from the 60's where they used three...
  27. C

    How many Amp turns around the Earth for this flux density?

    Someone is asking me how much current in a loop of wire the diameter of the Earth to make the same level of magnetism the Earth has? I hope I am asking this correctly. TIA Clark
  28. J

    Wire size and type for gain clone type amp?

    I have constructed a gain clone type amp based on the LM3886 chip from Texas Instruments. I have wired it using some available 16 gauge stranded wire. It is powered by a centertapped 34 volt (68 volt total) transformer that is fused by a 2 amp fuse. It is working with no issues however I would...
  29. ace130

    Find S/E in Filtres & OPAMP Circuits: A Complex Schema

    So this is the circuit of a filtre and it's complex schema : The question was find the fonction S/E .In order to find S/E , I had to sum up impedances in serie or parallel, for example R2 and Z2 have the same current so we put R2+Z2=Z', but can I sum Z1+Z' ? since they have different current...
  30. Y

    Please check my derivation of the gain of single ended diff amp

    I am having a very difficult time verifying the equations for full differential amplifier. I literally read all the articles I can find from Google. Here is one of the question I think the paper by Jim Karki is wrong. The equation is equation (9). I verified the rest of the equation already...
  31. A

    Help reading Noise Characteristic graph for sub-nanovolt amp

    These are the links to the specific product I am looking at and its noise characteristic graph. http://www.emelectronics.co.uk/a20.html http://www.emelectronics.co.uk/graphs/a20graph.htm I understand the graph for the most part, but I am confused about which one of the four filters that are...
  32. NFuller

    Finally finished: Tube amp project

    Thought I would share my latest project. I decided to make a stereo amplifier out of Vacuum tubes. I think I finally have the noise and distortion levels as low as I can get them. The amplifier outputs about 88W rms per channel before it clips the output. Here is the internal wiring This is a...
  33. C

    How can I connect a speaker to my amp without a physical wires

    I am trying to connect a second pair of speakers to my amp without the use of wires. It is really only one speaker position where running wires is impractical.
  34. Alkozy

    Two-Stage BJT Amplifier Homework: Solving for Input Resistance and Voltage Gain

    Homework Statement see pic in the attachment beta = 100 Homework Equations Rinput=Rth Vinput=VTH iB= ic/beta IE=ic /alpha iB=iE/(beta+1) gm=IC/VT Avo=-gmRC Av=-gm(RC||RL) Gv=-Beta[(RC||RL)/Rsig+(beta+1)re re=alpha/gm The Attempt at a Solution solving each stage separately. First DC analysis...
  35. Weightofananvil

    Question about 12au7 headphone amp

    Hey, I'm building this simple tube amplifier amplifier as a warm up to some hopefully bigger and better audio tube projects. http://diyaudioprojects.com/Solid/12AU7-IRF510-LM317-Headamp/ I realize the LM-317 is configured as a charge pump but I don't exactly understand its purpose, Could...
  36. whatphysics

    Finding closed loop gain and Ip and In current in op amp

    Homework Statement Finding closed loop gain and Ip and In current in op amp Homework Equations - The Attempt at a Solution I started by trying getting voltage divider for points between R1 and R2 as (R2/(R2+R1))Vs and between R4 and R5 similarly. And I'm not sure how to continue on. Any help...
  37. P

    Low DC amp through small circuit of 14 AWG copper wire?

    I have a 2 AMP regulated DC power supply, with variable voltage 3 - 12 v. If in a small circuit, i.e, small copper wire with 1 ohm resistor. Why am i not getting at max Amps?
  38. Helmholtzerton

    Eval op amp achieves +/- power from single power supply?

    Picture for reference is below. I'm confused as to how this is able to receive a differential voltage of +/- from a single power supply. (Yes, I know the picture says dual power supply.) Normally I have to short the negative to ground on one side of a dual power supply, and short the positive...
  39. I

    How does a buffer amp not remove all loading effect?

    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...
  40. Alaguraja

    What's the feedback for an op amp?

    What's the feedback for an op amp? And tell me the formula.
  41. Jayalk97

    Summing Op Amp Circuit Troubleshooting

    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...
  42. whatphysics

    Finding closed loop gain in ideal op amp

    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...
  43. U

    Which is better -- amp ground connected to frame or battery?

    There is this debate in car audio forums of this question whether it is better to connect your amp ground to the frame of the car or the battery.. basically they haven't came to a conclusion so I was curious what you guys think... Basically what I mean is that when you hook up an amp in the...
  44. N

    SR830 lock-in amp measurement problem

    Hello I am currently have difficulties trying to measure dc-modulated voltages while applying a dc current, via Sr830 Lock-in Amplifier (LIA). Basically, I apply an 2 GHz ac current (amplitude modulated@10kHz and referenced to the LIA for lock-in measurement) and a dc current to my DUT...
  45. O

    Electronics Determining Op Amp Gain.

    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...
  46. Planobilly

    How do I shield an amp setting on my work bench from EMI

    Hi, With all the various RF coming from things in my own house (cell phones, TV, cable modem, electric motors, etc.) and from outside I need to try to limit that interference while working on amps. Disregard for the moment, interference coming in through the AC mains. I also want to explore...
  47. Planobilly

    Photo of the new amp in the case

    Hi Guys, This was my first attempt at trying to make a case and covering it. I made a few mistakes and learned a good bit about the process. I think I learned enough to do a good job on the next one. Education is never cheap...lol The amp is basically a AB763 with a few mods. The current...
  48. Planobilly

    My latest crazy amp project photos

    It takes real machines to build big amps!..lol 11 tubes, 2 channels, tube reverb, 100 watts, channel switching, DC tube heaters...somewhere in all this I must have lost my mind!...lol I guess tomorrow I will see if this beast will work. It is by far the most complex amp I have dreamed...
  49. Planobilly

    Can you tell me if this amp design will work

    Hi, I am struggling with this a bit. I think this will work but I am not sure. Can you guys take a look and see if I have made any obvious mistakes. The B+ voltage should be around 480 VDC loaded. I am still working on the channel switching. [PLAIN]http:// Thanks, Billy
  50. Planobilly

    New '56 Fender Deluxe Amp Build - Photos & Info

    Hi, Thanks for all the kind help answering my goofy questions guys. Here is the results. This is a reproduction of a 1956 Fender Deluxe with modern case covering. The cloth is seat cover material from a vintage Porsche 911. The sides are black leather. Minor change to the the grid...
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