Questions tagged [amplifier]
An amplifier can be used to adapt the range of the signal to a requirement, to make it more robust for transmission, or to satisfy interface requirement (like input/output impedance)
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Differential gain of op amp
So I was reading the chapter on Op Amps in Microelectronic circuits by Sedra, Smith, the topic on Differential Amplifiers to be exact.
Here's the amplifier: https://i.stack.imgur.com/3qWzi.png
To get ...
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36 views
design Am circuit [closed]
Design and simulate an AM modulator in Multisim. The modulator should be based on transistor differentiator AM modulator followed by suitable tuned circuit and class B power amplifier, show using ...
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2answers
46 views
voltage to current converter using op-amp and MOS
I came across voltage to current (V2I) converter circuit. and I found Iout=Vin/R1. I have a few questions about it:
I believe the op-amp is in the negative configuration because v(3) & v(2) both ...
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31 views
Trans-conductance amplifier using CS MOS amplifier
What is the meaning of the text "Less control on input Impedance"?
Why did we add CS amplifier for this purpose?
4
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1answer
80 views
Would a suitably placed inductor stop audio feedback whine?
To give some context, I am designing a cosplay armor costume that somewhat muffles everything that is spoken while wearing it. I have a simple low power audio amp that I was intending to use to ...
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36 views
Making subwoofer for car, without amplifier
So, I have these two things and I want to achive a good subwoofer for my car: an 5.1 home theater system with a 20-30w 4ohm subwoofer and a radio player in my car with 4x45w 4ohm output for speakers.
...
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1answer
72 views
How to choose nodes for Thevenin equivalent circuit
I would like to know how do we choose the nodes for a Thevenin Equivalent Circuit.
For example, in the voltage divider, we compute the Thevenin equivalent circuit between the nodes where we would ...
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2answers
62 views
How filterless Class-D amplifier works?
The image below shows how a Filterless Class-D amplifier works:
The way I understand it: Vout(minus) is just the mirror image of the Vout(plus) but there was a certain phase shift(time delay?) ...
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3answers
40 views
Why do we use a wide-band amplification in order to reproduce a sharp pulse without distortion?
I was reading some content with regards to the Fourier Transform and the uncertainty principle. In the book I was reading that
Due to the uncertainty principle, in electronics we use a wide-band ...
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2answers
42 views
DC offset before signal being fed into an instrumentation amplifier from a bio potential source
I am trying to design an instrumentation amplifier, having 2 bio-potential sources as its differential inputs, each having peaks in the order of 10's of uV and a frequency band of 3-50 Hz. One of the ...
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1answer
38 views
How can I improve the common mode rejection ratio for TI ADS1299 ADC?
I am using 2 TI ADS1299 (home page, datasheet) devices with Raspberry Pi4 and I want to improve the common mode rejection ratio.
I don't understand the proposed techniques such as the isolation ...
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2answers
33 views
Error in the minimum value of the operational amplifier output
I designed a circuit to control the speed of a 24V coller. For this I used the operational amplifier TCA0372DW.
As I am going to control the output voltage through ...
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3answers
102 views
Explanations regarding the blocking of diodes in single phase rectifier
I have started an analog circuits course and have trouble understanding the behavior of such opAmps and rectifiers.
This is the circuit given as example, however there's no extra explanations ...
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1answer
92 views
What is the purpose of these capacitors?
I have an amp (denon pma-1060) that has small 330pF ceramic caps directly soldered between it's speaker outputs and the chassis. But I don't know what is the purpose of them. Why are they there?
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41 views
LockIn Amplifier Noise measurement
On my understanding, a LockIn amplifier use an internal (or external) signal source, set to a given frequency, say x. The system locks into that frequency, which means only that frequency can be ...
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35 views
Series current Feedback
I was tryig to build this circuit ("Series-feedback pair") from "Art of electronics" book (p. 150).
Since I do not have the exact components I tried to model it in LTSpice with ...
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3answers
74 views
Built difference amplifier “tail” vs. SPICE models
I am working on a difference amplifier example lab 5L.1 from Art Of Electronics Hands on Lab Course (I am not a student). I simulated three types of "tail" circuits using SPICE. Then I built ...
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2answers
63 views
Common emitter bandwidth and probing
I am trying to design a simple RF amplifier for a 1MHz AM signal (for low-power transmission). My modulator (JFET-based) outputs ~...
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1answer
58 views
I need help deriving the cutoff frequency of a negative feedback amplifier
I have the question and answer below for deriving the closed-loop cutoff frequency of a feedback amplifier circuit. I can follow the working out all the way until the last 2 lines, where the writer ...
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37 views
Match Digital Amplifier to Audio Speaker
I am working on a Raspberry pi audio project and need help creating the proper schematic.
I am given:
a amplifier detailed here
a vanilla audio speaker with 5 W rated input power and 4 ohm impedance
...
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0answers
27 views
Moving from ICF in-amp to traditional in-amp, removing bridge offset, driving ref pin with shunt regulator
Right now im using AD8237 with MCP4725 to remove bridge unbalance. I'm using 3x 1k Ohm resistors and one strain gauge arranged in Wheatstone bridge.
My circuit looks like that:
It works perfect for ...
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3answers
157 views
How do I design preamplifier and amplifier (for a speaker) circuits from scratch? [closed]
I am 3rd year electronics student.
I want to design a speaker from the circuit level.
As this is my first time, I have no clear idea how to start and where to start.
Can anyone please suggest to me ...
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1answer
36 views
Regulated Cascode TIA using a voltage amplifier with negative gain
I am reading this article.
Why in the article is it said that the v_sg increase when vx increases?
well, why does it use v_sg instead of v_gs for NMOS in the first place?
As I see it, VY must be ...
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2answers
73 views
Precision amplitude 600kHz square wave generator
I'm looking for a circuit that creates a precision amplitude square wave of 600kHz (50% duty cycle). The amplitude of the square wave needs to be 3Vpk-pk +/-10mV, but can be DC offset. The output of ...
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38 views
How The no Contact Voltage Detector circuit work?
I saw the no Contact AC voltage detector circuit on some video on youtube and tried to make the circuit except that I wanted to replace it's led with an active buzzer with internal oscillator
Problem ...
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2answers
43 views
Control transmitter operation
So I'm new to servomechanisms and am initially unclear on 2 things.
For a control transmitter, I know that it converts the shaft position to an electrical signal. How exactly does it do that?
If ...
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2answers
47 views
Car amp burned out component [closed]
I need help identifying this component on the board of my car amp that has burned out. Electronic circuit board knowledge is pretty much zero for me. But Iām good at fixing stuff so I want to try to ...
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52 views
I have a question about the datasheet for AD8330 VGA (variable gain amplifier)
I don't have much experience reading datasheets. I was reading the datasheet for AD8330 VGA. I did not understand what the difference is between VDBS and VMAG. Can someone elaborate on that?
It's ...
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3answers
117 views
What's wrong with this audio amplifier and stereo to mono circuit?
The image below presents part of a schematic of an MP3 decoder (VS1003) with stereo -> mono conversion and audio amplifier to connect a speaker.
The problem is that after assembling the PCB barely ...
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1answer
79 views
Amplification of Bolometer
How would one measure the microvolts change in a 50kĪ© Bolometer, as a result of the radiation impinging on it?
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1answer
47 views
Roland MicroCube GX MOD: bluetooth aux in [closed]
I own a Roland MicroCube GX guitar amplifier (see https://www.roland.com/global/products/micro_cube_gx/); I'm pretty pleased with it.
This particular model has, in addition to the guitar input jack, ...
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1answer
36 views
Finding poles by inspection
I have a question regarding finding poles by inspection. The technique that I know is
Find the resistance R tied from the node to AC ground.
Find the capacitance C tied from the node to AC ground.
...
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2answers
670 views
Where do zeroes come from in a circuit?
I'm having difficulty fully understanding how exactly a zero is created in a circuit. I would like some way of visually recognizing (without computing a transfer function) that a zero will be present, ...
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3answers
43 views
What is the definition of “the loading of feedback network on the input/output side”?
There is the following example:
simulate this circuit – Schematic created using CircuitLab
Its loading of the feedback network on the input side is 40kohm in series. Its loading of feedback ...
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3answers
58 views
Do parallel LNAs at 90-degrees to eachother reduce the noise floor more than side-by-side?
Wiring amplifiers in parallel in a summing configuration improves the signal to noise ratio because amplifier noise in each LNA is uncorrulated. However, external noise sources will still be a factor ...
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1answer
45 views
Driving Stepper Motor with Sine Wave
I am attempting to drive a stepper motor where each phase draws 1 A at 3.5 V using a sine wave oscillator that outputs two signals 90 degrees out of phase with one another. At the outputs of this ...
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3answers
106 views
Mic amplifier noise
I build a mic amplifier for a standard hands free (Apple 4-pole jack). However, even without anything plugged into the jack there's audible noise at the output (MIC_IN in diagram). It sounds like ...
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3answers
110 views
Adding a base resistor in a common emitter amplifier
According to Wikipedia, a common emitter amplifier doesn't have big stability without an emitter resistor. When putting an emitter resistor gain is reduced. Why don't we put a base resistor in order ...
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1answer
52 views
Long tailed pair
How do I adapt the long tailed pair to fit my requirements?
I've seen circuits where they use 9V Vcc with 10k resistors.
From my understanding the resistors are there to prevent floating base from ...
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1answer
77 views
IC design to amplify from microvolt to volt for making a comparator
I am developing an IC in CMOS technology which, among many other things, I need to compare one signal with another. I need a square wave signal above a limit to result in VDD, and signals below that ...
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208 views
Op-Amp as an error detector
In the design of an AC servo position flight control surface system, a feedback system compares the output position to the pilot's input command signal.
How is an operational amplifier used as an ...
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3answers
148 views
Amplifier design help
I am designing a two stage Amplifier for class, and I had asked for help before on the forum which helped a lot.
Input is a 1v sine wave.
My design was for a 5 voltage gain however I am only seeing 2....
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1answer
82 views
I need help identifying this potentiometer
It is off of a Hifonics mono channel car audio amplifier.
This is the back. It has 6 prongs and was removed from the gain spot on the amplifier:
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0answers
27 views
Necessary Bandwidth of Current Shunt Amplifier in FOC + SVPWM motor control
I am designing a BLDC motor controller using sensorless FOC + SVPWM, planning to use a shunt to measure current, and using an observer to determine the rotor angle. I was wondering, what bandwidth do ...
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1answer
69 views
Biasing of CE amplifier with emitter resistor for specific gain
I am trying to design a Common-Emitter amplifier to the following specifications:
Midband voltage gain of 50
Frequency range 100Hz to 20kHz
Load \$5k\Omega\$ with a coupling capacitor (not shown ...
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2answers
83 views
Simple method to calculate output impedance of source follower
Output impedance of source follower without Rs would be 1/gm. However, if you add Rs the ...
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1answer
49 views
Mosfet Amplifier design help
I am currently designing a MOSFET common source amplifier for my electronics lab class. My issues is that currently I am unable to obtain a gain out of my current circuit design.
I am using a 2N7002 ...
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2answers
30 views
MOS Cascode - Shielding Property
I have some doubts trying to understand the "shielding" property of a cascode device.
I understand that a cascode provides a higher output resistance which can help to increase gain. However,...
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1answer
30 views
RF amplifier biasing in QUCs
I have selected an infineon BFP840ESD BJT to work with in the design of a low noise RF amplifier. I'm trying to use Qucs Studio to simulate it.
From the datasheet I select my bias conditions with as ...
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1answer
38 views
Buffer amplifier, minimizing PCB footprint
I have a circuit that needs to pass 22 analog signals through a buffer amplifier before feeding them into an ADC (due to the relatively high impedance on the analog signals). I plan to use non-...
