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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1answer
283 views

Output voltage in MOS cascode amplifier

I'll give a background to my main question:- In a simple NMOS as shown, while constructing the small signal model of the MOSFET, when there is no resistance between Vdd and drain, NMOS is modeled ...
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2answers
114 views

Confusion with the gain concept of an amplifier

Before asking my question I want to briefly write about the basic meaning of the power gain. Below is a model of an amplifier: It shows the source input and amplifier output from left to right. ...
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1answer
630 views

Yagi Calculator vs. Bruteforced values?

I started trying to build my own Yagi. So i ran into maybe some very well known Websites that show how to do it - however, i wanted to try with some theory first, before actually attempting to build ...
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1answer
57 views

how to adjust drain bias to keep power dissipation constant (HEMT)

I am reading a chapter in a thesis about using HEMT (high electron mobility transistor) as a cryogenic amplifier. The measurement scheme is to use the gate voltage fluctuation's influence on the drain ...
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1answer
320 views

Gain of an experimental first order step response

I have a pwm driven DC motor control system with magnetic encoder that measures the output shaft speed and outputs the RPM values every 50ms over serial comms to plot a graph of RPM vs Time. The ...
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1answer
211 views

Simple op-amp frequency response

In my textbook, there are two interrelated equations. 1. wb = wt / (1 + R2/R1) 2. wb = wt / Ao where ...
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1answer
84 views

High gain amplifier ADA4528

I am trying to make an amplifier which should amplify signals from at least 10uV (lower better) to around 100mV or above. The signals range from a few Hz to around 100kHz. Adjustable gain is also ...
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1answer
612 views

RF Output Power vs Antenna gain

I have a RF device which work on 2.4 GHz and Output power is 30 dBm (1 W), RF output is connected to a whip antenna (gain 2 dBi, omidirection), distance track between RF pad to antenna is kept as ...
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0answers
204 views

Maximum Gain For Chopper Stabilized Instrumentation Amp (MCP6N11)

I am using a Microchip MCP6N11 chopper stabilized instrumentation amplifier to amplify the signal from a MPX2300DT1 Wheatstone bridge pressure sensor. My schematic is attached. As shown the gain is ...
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1answer
344 views

Audio volume levelling / AGC for spectrum analyser

I'm busy building a preamp, and want to include an LED-matrix spectrum analyser on the front panel (for aesthetics, not accuracy!) I've set up a circuit that uses a couple of MSGEQ7 chips to analyse ...
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1answer
59 views

Antenna Directivity

How to make an antenna more directive by changing its physical size/scalling? My current approach: I should make the antenna bigger. A directivity is a Fourier transform of illumination, distribution ...
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2answers
933 views

Resistive T-network

Can someone explain to me why this negative feedback resistive T-network simulates a 10M ohm resistance ? The overall closed loop gain is -100 because 10M/100k = 100.
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1answer
243 views

Effective area or effective aperture of antenna

The effective area simply represents how much power is captured from the plane wave and delivered by the antenna. The explanation begins oft with assumption that antennas have the same polarization. ...
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2answers
285 views

2 cascaded transistors- where is Vout of a transistor when there is a shorted collector resistor?

I have circuit drawn in AC, they were 2 cascaded BJT transistors, and I have changed them to the hybrid pi model. I wish to remove the source and load in order to write a general gain equation for ...
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2answers
172 views

Gain problem of inverting opamp

I'm implementing the circuit in the schematic on the breadboard. Difference of inputs V1 and V2 is about 5mV. Differential opamp has gain of 17,4 Inverting opamp has gain of 26 First problem: I ...
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605 views

why does this approach neglect the output resistance of the bjt in calculating gain?

This is the question that I would like to ask about. My question is with regards to finding Vc for question 3. This is the memo for the question: However, I have a problem with regard to how they ...
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856 views

Using LTSpice to find the gain of NPN-PMOS folded cascode

I am trying to use LTSpice to find the gain of NPN-PMOS folded cascode. Below is the question prompt: In the problem, the parameter specifications are as follows: \begin{equation} \beta =100,\:V_A=5V\...
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55 views

gain of inverting op amp with resistor on input

I´m trying to figure out the transfer function of the attached op amp circuit. I came to the conclusion that v_out = - v_in as as the two resistors in the upper path are equally sized, and the non ...
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1answer
101 views

What kind of software I can use to plot graphics like this? And how is this plotted? [closed]

I am trying to plot the transfer function of a circuit. What kind of software I can use to plot graphics like this, without using circuit simulation software? I would like to understand things ...
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1answer
752 views

Cascaded Amplifier Circuit Analysis Problem

I have this homework problem for my electronics class and I'm in need of assistance. Here is the original problem statement: This is what I have after drawing the circuit: My professor always ...
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1answer
739 views

Transconductance of a device

I would like to know what does it mean when someone says "that the transconductance of a FET or MOSFET is less compared to that of a bipolar junction transistor (BJT)". I even heard someone saying ...
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1answer
6k views

Mosfet Voltage Gain in common-source configuration

I have some doubts about this so-called transconductance which can be either calculated for BJT or for FET transistors. As far as I know, since BJTs are current controled devices, its transconductance ...
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165 views

finding the voltage gain for an amplifier

simulate this circuit – Schematic created using CircuitLab Hello all the circuit provided represents the small signal model of a MOSFET amplifier. I am being asked to find Vo/Vsig which is the ...
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1answer
68 views

Correlation between DC & RF voltage gains

I have the following question: how is the DC voltage gain in transistors (gm/gd ratio) related to RF gain? Can good RF gain be expected from a transistor with good DC voltage gain? Can anyone ...
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3answers
955 views

finding open circuit voltage gain

below I have this schematic to find the open circuit voltage gain. This circuit basically utilizes three resistors from which R_f is supposed to be the internal feedback resistor. It also utilizes the ...
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1answer
102 views

Differential gain of an op-amp and feedback

In an op-amp, we know from basic electronic courses that vo = A(v1 - v2) Assuming large differential gain and finite output, we get that (v1-v2) is very very small, ideally zero. In a university ...
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4answers
8k views

Is the roll-off gain of filters always -20 dB/dec?

I have been doing some preliminary lab calculations since I have an intense session coming up next week. I have to solve many filters, most of which are just basic, passive RC filters; others form ...
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4answers
912 views

What is the closed-loop gain in this op amp circuit?

For the op amp below Open-loop gain is \$A=2\times10^5\$ Input resistance is \$R_i=2\,M\Omega\$ Output resistance is \$R_o=50\,\Omega\$ I am asked to calculate the close-loop gain \$Vo/Vs\$ and ...
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1answer
119 views

Find optimal gains transfer function

I have the following closed loop transfer function: $$G(s) = \frac{K(s^2 + 200^2)}{0.05s^3 + (1+K)s^2 + 200{K_v}s + 200K}$$ Where \$K\$ and \$K_v\$ are gains. My goal is to find the optimal gains ...
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63 views

Headphone Amp Impedance Select Switch

I'm designing a headphone amplifier, and I'd like it to be compatible with both 32 ohm and 600 ohm headphones. Therefore, I figured I could introduce a switch which allows the user to change the gain ...
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2answers
82 views

How to extract pol & zero data from amplifier's data sheet?

I am looking at the OPA548 amplifier's data sheet and trying to extract the corner frequencies but i am unable to accurately do it, as i can only make assumptions based on the open loop gain/phase ...
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1answer
93 views

Circuit analysis to obtain the gain of an inverting Op-Amp

My problem is that I don't know how to prove that the gain of this circuit is given by the following relation. \begin{equation} G=\frac{U_o}{U_i}=-\frac{R_2}{R_1} \end{equation} I have the feeling ...
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1answer
58 views

Gain of the amplifier

If we have open loop gain of 2dB or 3dB what happens if we use this in closed loop (except the gain reduction)..i mean how does gain affect on the output of feedback amplifier.
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1answer
4k views

How to add dc offset and gain to a given signal

Before I start, I just want to mention that I am a premed student. However, I want to build a DIY amp for my headphones since my computer can't properly drive them so I decided to take an electronics ...
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2answers
91 views

How to determine the gain of this op amp

I want to know how to determine the gain of the op amp signaled by an arrow, or get an ecuation described in terms of V1 that explains what’s going on in there. For the general problem, what I need to ...
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1answer
49 views

How to calculate the feedack resistor in this configuration

I try to simulate the input stage of the ADC feeding circuit. ADC is 0-3.3V. The circuit: The Vin input signal: The output: The signal is shifted properly but the gain is lower than I expected. ...
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2answers
980 views

Roll-off of a filter

I know that the roll-off of a transfer function gain is given by: $$20\log_{10}\left(\left|\text{H}\left(\omega_2\right)\right|\right)-20\log_{10}\left(\left|\text{H}\left(\omega_1\right)\right|\...
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1k views

How to identify which transistor is in active region and which one is in saturation?

In the following amplifier circuit, voltage gain is required. Capacitors act as open circuit for DC analysis but short circuit for AC analysis (consider capacitor value to be very big). Now MOSFET ...
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1answer
752 views

Negative Gain and in a common gate FET amplifier [closed]

We conducted an experiment involving frequency response in common gate FET amplifier. The results at different frequencies from 10Hz to 1MHz are obtained and we got a negative result in the first few ...
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2answers
106 views

differentiating circuit voltage gain

Hi! I came across this question in lab, and it's been several years since I last done analog circuits. The voltage gain here in this op-amp should be 0.707 (-3db cut-off), and it asks us to find the ...
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1answer
267 views

Calculating gain of ICF amplifier

I'm designing a circuit with an ICF (indirect current feedback) amplifier, and am trying to calculate the gain of the resultant circuit. Using the AD8237 I followed the example here when designing ...
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3answers
1k views

What does “normalized” mean in this datasheet?

I came across the graph below in ONSemi's 2N3904 datasheet that depicts the DC current gain. I don't understand what "normalized" means. I've read other explanations by Googling, but found all of ...
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3answers
306 views

Gain not containg the output, non ideal, resistor

I was working a mathematical model of a non ideal op-amp circuit and I saw a slide in the following presentation: The question I have is the following: Why does the close-loop gain \$\frac{\text{V}_\...
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1answer
2k views

Increase gain of electret microphone amplifier powered by aircraft radio?

I am trying to build an amplifier to allow a cheap electret boom microphone to be used with an aircraft radio, but am unsure how to increase the gain to a usable level. I derived the attached design ...
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3answers
691 views

Do the temperature coefficients of the resistors in the LM399/LM199 “Portable Calibrator” significantly effect the output stability?

I'd like to know how voltage reference stability is obtained in products like 6.5 digit multimeters that use LM399 as a voltage reference in spite of using two gain resistors. Let's assume an ideal ...
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1answer
2k views

Phase Shift Of Operational Amplifier [duplicate]

From the datasheet the open loop phase shift is given as 90 degrees for a range of frequency. But why doesn't a a normal open loop inverting amplifier does not show this characteristics of the phase ...
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2answers
113 views

Power/current limitations of variable gain amplifier

I am working with a motor invention and I am wondering about the utility of variable gain amplifiers. I wonder how to achieve a high output current with such an amplifier¿
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5answers
5k views

Reduce audio amplifier output power [closed]

I need some help to adjust the volume of the amplifier. It is a 2.5 W amplifier and it has to be connected to a 2 W speaker. I want to reduce the gain of the amplifier in order to avoid damage to the ...
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3answers
8k views

Transfer function gain [closed]

\$H(s)\$ is the transfer function and we're looking for its magnitude gain. I went from the Laplace domain to the frequency domain by replacing \$s\$ with \$j\omega\$. However, the solution didn't ...
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3answers
2k views

where to add gain and volume controls to LM386 guitar amp circuit?

Im trying to make a super simple guitar amp. heres the circuit using an LM386 operational amplifier: What exactly would affect gain but not volume, and volume but not gain? In the example circuit on ...

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