Questions tagged [gain]
Simply the ratio of output signal to input signal, this dimensionless quantity is a measure of the amplification of a signal which may be represented by voltage, current of may even have a digital representation. A very general concept sometimes used to describe attenuation (when gain < 1)
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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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Opamp: Does the openloop Gain changes depending on the Input stage?
In case for bipolar Input stages on Opamps: does the actucal Openloop gain changes depending on which input stage, n or p channel is used? (which depends on the applied input signal)
Could not find ...
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Voltage gain in common emitter BJT amplifier (specific example)
What is the AC voltage gain in the following common emitter BJT amplifier? We are also given that for the BJT \$\beta_{DC} = \beta_{ac} = 150\$.
simulate this circuit – Schematic created using ...
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3answers
144 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
58 views
Op-amp input signal problem, mismatched
My signal generator drives a 50 ohm coaxial cable, terminated with a 50 ohm to ground at the input of a voltage amplifier.
However, when I look at my input signal over frequency, it doesn't behave as ...
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81 views
Op-amp with constant output voltage (Peak to Peak)
I am new to opamps and am trying to amplify a variable frequency sine wave to a constant 5V peak-to-peak using opamps.
The input signal amplitude changes with frequency, but the opamp should always ...
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1answer
48 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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50 views
Automatic gain control circuit with dc offset
I have a circuit that takes a sine wave amplifies it a little bit but also adds a DC offset of 1.5V. It works perfectly no matter the input volume. Now that I am reworking everything it would be nice ...
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59 views
distance between linear and non-linear function of op-amp system
I have a circuit which I have taken a picture of as you can see, in which i have values of
$$R1=1k\Omega,R2=10k\Omega,R3=10k\Omega.R4=10k\Omega,R5=20k\Omega$$
and sine input signal with off-set value=...
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“Coupling” gain-setting resistors in a single-ended source, differential amplifier?
I am working on a fully differential amplifier design that receives a single-ended differential voltage from a piezo sensor.
I computed a theoretical gain and selected appropriate resistors and it ...
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1answer
52 views
Troubles with mic preamp for headphones with integrated microphone
I am designing a preamp intended to interface with a microphone in common headphones (e.g. apple earpods, or sony headphones with a microphone) which will then connect to my ADC's inputs.
I've ...
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44 views
Automatic gain controller gain action
Can you guys explain to me how the turning on of Q2 and the charging of C2 increases the vgs of the FET? An equation would be helpful.
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[op amp - Gain current source - current reference]
I have a question about the formula to consider for calculation of the gain for the electronic bellow.
Thanks for your support.
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129 views
What are the units used in Shannon formula calculation?
I'm a CompSci student with absolutely no background in wireless communication who recently needs to do something with the Shannon formula:
$$
R = W log_2\bigg(1+\frac{P_t H^2}{N_0 W}\bigg)
$$
I need ...
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2answers
48 views
Two antennas, one board
Everybody.
I have a doubt. If I use one connector like this:
https://www.data-alliance.net/rp-sma-t-splitter-y-adapter-joiner-join-2-antenna-cables-to-one-connector/
In one board and connect two ...
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0answers
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Signal clipping in cascade transistor amplifiers
The two-layer voltage amplifier circuit can transfer a signal of up to Vi = 50 mV to the output without clipping.and 1st stages gain Av1=-6.41 . +15 volt is ...
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Question on operational amplifiers
1.
The following two questions refer to the circuit below.
Consider a non-ideal op amp where the output can saturate.
The open loop gain A = 2 x 10^4 , where vo =āA*Vs
The positive supply voltage ...
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1answer
54 views
Chebyshev filter - theoretical vs simulation gain
Question is about the gain peak (or maybe more suitable would be growth) ocurring in higher frequencies (>20kHz) in Chebyshev filter 4-th order in simulation (simulated using Bode Analyzer in NI ...
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197 views
DC Gain of the System
I'm trying to design a feedbcak loop compensator and I'm following the instructions on power supply cookbook.
Book has calculations for DC gain like equations below:
in my situation Vin: 40V-60V and ...
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2answers
67 views
Closed Loop Transfer Function - PD Control
For the following control system, I am trying to find the characteristics of the system.
I have firstly found the closed loop transfer functions \$T(s) =\frac{C(s)}{R(s)}\$ , to be:
\$G(s) =K_p(s+9)...
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1answer
68 views
LTSpice produces incorrect simulation for Class AB amplifier
I have been building a Class AB amplifier simulation using LTSpice.
While it simulates well for transient analysis (voltage gain of 0.9 at peak),
using ac analysis the the voltage gain drops to 0.268....
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0answers
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Troubleshooting butterworth bandpass gain stage issues
I am having issues solving the gain stage section of my bandpass filter design. I used a multiple feedback 6th order lowpass and a 6th order sallen-key high pass to get a bandpass filter with cutoff ...
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2answers
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A question about antenna gain and signal property
I have an antenna with a somewhat constant gain "X dBi (theta, phi)" in the frequency range of interest.
With this antenna we receive a radio signal with an amplitude of "Y Volt (t)".
The signal is ...
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2answers
966 views
What does m% stand for?
What does m% mean?
Like in this datasheet from TI at the gain error graphs: http://www.ti.com/lit/ds/symlink/ina149-ep.pdf?&ts=1589388038122
Is it supposed to mean per-cent-mille (10^-5) or per-...
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1answer
63 views
Headroom of cathodyne phase inverter (in vacuum tube amplifier)
I know that gain of cathodyne is almost 1, so if it's going to produce 12V peak output, it has to take 12V peak input.
However, if the bias is set to something like (-)1-1.5V, then peak voltage of ...
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2answers
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How do I calculate the DC output of this specific low pass filter?
Hi!
I am having some trouble understanding how to calculate the DC output of this low pass filter.
Also are my calculations correcet that the transfer function of the filter is:
$$\frac{R_{\text{8}}*...
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4answers
211 views
Load line and voltage or current gain
Why does a steeper load line gives higher current gain, while a flatter line gives higher voltage gain? I read multiple tutorials where they only provide a graph without explanation and I can't ...
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0answers
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Voltage phasor problem in textbook wrong?
An example in my textbook gives this problem:
Find the phasor representation of vo = -5cos(2000Ļt+25Ā°)
Answer: 5<-65Ā°
Shouldn't it be 5<-155Ā°? You subtract/add 180Ā° to get the negative of ...
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3answers
60 views
Why resistance of load resistor determines gain of common emitter amplifier?
Most schematics I saw take output signal from collector, not from load resistor. So why we are calculating gain by dividing load resistor by emitter stabilizer resistor (or re - equivalent dynamic ...
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1answer
52 views
Colpitt oscillator transfer function
Can you guys please help me find the symbolic transfer function Vout/Vin in this colpitt oscillator ?
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4answers
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Is it normal that with the same op amp but with a different voltage input, the amplifier gain is different?
So with my one of the part of my circuit below, I only wanted to see the effect on the op amp if I changed the input voltage (knowing that the inverting input is 0). My first thought was that even if ...
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2answers
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Common collector :current amplifier or voltage follower?
I want to construct a simple voltage regulator like this one:
simulate this circuit – Schematic created using CircuitLab
However there is something peculiar: the voltage on the emitter is ...
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1answer
29 views
Frequency dependent behavior of an inverting configuration of an opamp
I am a third-year chemistry student. I have essentially the understanding of a second-semester physics student when it comes to circuitry and electrical engineering. For reference, I know what gain is ...
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1answer
102 views
Opamp gain calculation
May be a very basic question, I am a chemical engineer with limited electronics knowledge.
The circuit is a potentiostat with the current source \$I\$ being a sensor electrode.
I was looking for a ...
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2answers
129 views
Mid-band magnitude gain of a Cascode Amplifier
Looking to do some theoretical analysis on a Cascode Amplifier and compare it to a simulated model. Please see the circuit schematic below followed by the bode plot developed in the simulation ...
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2answers
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Help selecting feedback and ground resistors for a gain and offset circuit
I have an input signal from -3.3V to 3.3V and the ADC I would like to use can only read from 0 to 3.3V.
I also have access to a stable source of power at 3.3V.
From previous visits, I have tried to ...
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1answer
77 views
Can the two same current monitoring ICs give different results?
Have trouble testing of 30 pieces INA250A4PWR circuits like below. Produced as PCBA.
According to test results 21 out of 30 have mainly 1.98 V/A gain ratio.
But, 9 out of 30 have mainly 1.55 V/A ...
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2answers
52 views
Op amp output DC operating point variation with load current
Consider a cmos op amp in non inverting configuration. For a small load current, we expect the output DC voltage to be the input DC voltage multiplied by closed loop gain. As the load current is ...
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2answers
181 views
Bandwidth of pentode amplifier
Why is the bandwidth of pentode amplifier larger than the bandwidth of triode amplifier?
I have searched the following books but can't find the answer:
Electronics devices and circuits by Rajiv ...
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1answer
45 views
High gain and high modulation frequency photodetectors [closed]
I have been reading more into the gain of a photodetector and how the system works. We are picking up extremely small signals and need to use a detector with a gain of around 1.0 Ć 10^7 but preferably ...
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1answer
17 views
Global and Individual Gain Setting on 16 Channel System - Analog Solution
I am working on a system with 16 analog channels. Each channel has an individual amplifier stage (for the sake of simplicity assume an inverting amplifier for each) that then feeds into an ADC.
How ...
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1answer
47 views
Antenna gain relative to input power
I have purchased a circularly polarized antenna with a gain of 2.54dBi at 1W. If you require additional specs please let me know. My question is does the gain of the antenna equals the multiply of the ...
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44 views
How to make a preamp that is ON when input is a MIC but OFF when a LINE level?
My question is very simple:
Is there a way to create a "preamp" circuit that is automatically ON when there is a MIC connected (for example, a desktop PC microphone) but OFF when there is a LINE ...
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2answers
41 views
Op Amp gain modification from kenwood krf-7060d
Hi, I have an kenwood krf-7060d, which has an subwoofer line out that is very very "quiet". The top part of the schematic has the final opamp (sw out) before the acutal output. Can someone tell me ...
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Using a PGA to scale input voltage ranges?
I have a current design of a circuit which works well, but I am needing to make a few extensions to it. I am working on a 4 channel oscilloscope. Each channel must be able to take various ranges of ...
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Alternative to potentiometer for setting guitar volume
I'm trying to build something to change the gain of a line- or instrument-level signal very steeply using a microcontroller, to use as a guitar tremolo pedal. I've been looking at digipots but can't ...
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2answers
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Can someone please explain this Bluetooth Antenna Test Result, I am new to RF?
This is the test of a Bluetooth (BLE 5.0) passive antenna test result. I am new to RF and do not know how to properly interpret this result.
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1answer
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Can someone how to find this voltage gain neglecting r0
I'm trying to figure out why my professor starts off the way he does when trying to find voltage gain. How he starts off is shown in the last picture. Any explanation would be appreciated.
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Setting gain on Improved Howland current source (best practice)
I understand that you can set the gain of an improved Howland by setting the the ratio of resistors \$R_2\$ and \$R_1\$ and/or the value of \$R_{\text{set}}\$.
Is it better to leave the ratio of \$...
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2answers
57 views
Finding 70% Voltage Point
Let \$v_1\$ be the input AC voltage and \$v_2\$ be the output AC voltage such that gain \$\dfrac{v_2}{v_1} = \dfrac{A+jB}{D+jE}\$ where \$j = \sqrt{-1}\$. How should I find the 70% point (the point ...
