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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3answers
144 views

Thoughts on this single-stage BJT amplifier?

I've been self-studying electronics and am currently trying to design a high-gain single-stage BJT amplifier. Here is what I have so far: Q1 serves as a current source "active load" for ...
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74 views

Does the antenna design equate to the range?

There are a ton of different antennas out there, here specifically I'm talking about directional antennas. Options include Yagi-Udas, parabolic, LDAP, etc. antennas. All of these have somewhat of a ...
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1answer
49 views

Way of calculating Gain of Yagi-uda antenna at a particular location

Suppose that I have a 9-element Yagi-uda Antenna. My goal is to calculate the gain function of the antenna as function of zenith and azimuth angles, i.e. \$G\left(\theta, \psi\right)\$. As far as I ...
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1answer
74 views

Using an oscilloscope to measure the gain of an op-amp circuit (with capacitors)

I have an upcoming laboratory exam where we have to construct an op-amp circuit (from our experiments the circuits were always varied and probably will be a bit more difficult on our exam.) We are ...
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1answer
45 views

Voltage gain of a differential amplifier with tail resistor

Suppose the following differential amplifier: simulate this circuit – Schematic created using CircuitLab To calculate the differential gain, I take advantage of node P being an AC ground and I ...
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1answer
51 views

Gain Value For Modified Differential Amplifier Circuit

I am trying to analyze the following differential amplifier circuit and am wondering how to calculate overall gain (it will be fed with two copies of the same audio waveform 180 degrees out of phase ...
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55 views

Output voltage at different output optical chopper frequencies

I have a circuit as shown in the figure and I am using it to extract output voltage of thermopile (to determine the time constant of thermopile ) at different output frequencies. The optical chopper ...
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2answers
159 views

How to increase CE amplifier gain to 12?

The gain needs to be increased to 12, currently it is at 10 but I cannot seem to increase this any more. The circuit topology cannot change, but the component values can - except R4, the 56 kΩ ...
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1answer
58 views

Friis Free Space Equation for Received Power

According to Friis Equation the received power is directly proportional to the square of the wavelength or inversely proportional to square of the frequency. But is this not misleading. There is ...
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2answers
72 views

Antenna radiation plot and negative gain values

In general, how to interpret the negative gain values on antenna radiation diagram plot? I have attached an example. My guess is that they represent some value relative to some reference value. If so, ...
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1answer
123 views

Stable 94 dB gain op-amp amplifier

I would appreciate suggestions or best practices for designing a stable amplifier. My goal is to design a 94 dB gain low-noise op-amp amplifier for a 100 kHz signal with a bandwidth of 10kHz. At this ...
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67 views

Gain of photodetectors

I found this in a lecture about "Optical Wireless Communications." It is slide 15. Does anyone have idea how gain was computed?
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140 views

Voltage Gain Expression

I had a homework problem where I was supposed to find an expression for H(ω) = Vo/Vs of the op-amp shown below: However, when I found my own expression, it turned out to be a very messy fraction that ...
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312 views

Why is the output of an Op-Amp given by the open loop gain multiplied by the input differential voltage

When designing op-amps at the transistor level, the op-amp output is given by: vout = Aol(vinp - vinm) where vout, vinp and vinm are small signal changes in the output and input voltages. How come ...
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1answer
59 views

Why does gain of my INA2332 change with increase in input voltage?

I'm building an IoT circuit for sensing resistance change using Kelvin's 4 wire. I have implemented a constant current source that supplies my two sensors connected in series with 50 mA. The output ...
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54 views

Problem with parasitic capacitor in feedback path in inverting circuit

I want to meet following conditions: Gain: 27.74 dB Input source resistance: 6800 Ohm Bandwidth: 15Khz (I actually need to have a flat response until 10khz and I do not care about the rest of it) I ...
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1answer
93 views

Why is CMRR defined differently in open loop and closed loop configuration of opamp?

I have recently been studying "Linear Integrated Circuits" and I am currently studying about opamp circuits. The books I am referring are Microelectronic Circuits (Seventh Edition) by Sedra ...
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4answers
86 views

Calculating the theoretical frequency response and static gain of a filter

I'm trying to calculate the theoretical frequency response and static gain of this low-pass filter. As far as my knowledge goes, calculating them using experimental means would be simple, but how ...
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2answers
185 views

Relationship between antenna impedance matching and gain

This is my first year designing and simulating antennas and I try to understand the relationship between impedance matching and gain. I stumbled upon the term of antenna efficiency which makes perfect ...
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2answers
106 views

Cut-off frequency of simple transistor circuit with capacitance between input and output

I have the following problem: - simulate this circuit – Schematic created using CircuitLab For the amplifier shown in circuit 1, the open circuit voltage gain at low frequencies was calculated ...
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1answer
91 views

Cascade BJT amplifiers gain calculation

I've been trying to cascade BJT amplifier to get a gain of 800. My input is 10 mV, and I want an output of 8 V. My question is, how does the gain of common emitter amplifiers work? I've created a ...
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1answer
61 views

Overall Gain for Mixer Circuit

I am working on an audio mixer circuit for balanced studio gear. The circuit consists of two unity gain balanced line receivers (THAT1200), going into a pair of voltage dividers controlled by a shared ...
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0answers
28 views

how to derive the DC gain of IPS stage?

I am reading Bob Cordell's book,Designing audio power amplifiers. And here is a basic 50-W power amplifier. Q1,Q2 compose a basic IPS circuit. It shows how to derive the DC gain of IPS part: The ...
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1answer
88 views

Why is there a minus on the voltage gain of a common emitter?

In a common emitter amplifier with \$h_{re}\$ and \$h_{oe}\$ unimportant, and a load $$R_{CL} = R_C//R_L$$ I'm studying the gain voltage $$ A_v = \frac{v_{ce}}{v_g} = \frac{v_{ce}}{v_{be}}$$ So $$i_c =...
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1answer
56 views

Expected voltage on external gain resistor pre-amp

I want to build an amplifier with digitally controlled gain, using the THAT1510 pre-amp IC. The IC provides two pins to set the gain, using resistors. I want to switch between resistors with analog ...
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1answer
79 views

Gain of transimpedance op amp

I am trying to calculate the gain-bandwidth product of a project where I am reading photodiode output current measurements. I aim to find an op-amp to buy to use as a transimpedance amplifier. The ...
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2answers
162 views

Input bias current and offset current calculation for an LM741 op-amp

This is my circuit diagram: The bias current of the LM741 op-amp is 80nA. The offset voltage is 1mV. The LM741 has relatively large current offsets, voltage offsets and input bias. I calculated the ...
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4answers
231 views

What is the small signal gain for this circuit?

The question looked easy at the first sight. I found the quiescent current through the BJTs. I can say that |Vbe| = 0.7 V for both BJTs. Therefore, current through 1 kΩ below Q1 = 2 mA. Similarly, ...
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1answer
46 views

Calculating N-type enhanced MOSFET gain with two different equations brings me a different result?

Hi, take a look at this problem from my notebook. Leave alone the fact that the resistor should actually be 1,111.111, it is not related. If they claim that VGS=2 and Vs is connected to ground it ...
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1answer
73 views

1-dB compression point is in the range of -20 to -25 dBm

I am reading the Razavi's textbook RF Microelectronics 2nd edition p. 18. It says 1-dB compression point is typically in the range of -20 to -25 dBm (63.2 to 35.6 ...
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2answers
51 views

OP-Amp virtual gnd to real gnd gain control [closed]

Can someone please explain why a potentiometer from op-amp virtual ground to real ground control the gain?
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1answer
159 views

How can we find the voltage gain of a BJT circuit if the Vin and Vout are on different transistors?

I am trying to find the voltage gain of the circuit below. I drew the small-signal model for it (shown below). I know the formula for finding the voltage gain of a common-emitter BJT with and without ...
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34 views

Can I multiply the magnitude of two cascaded amplifiers?

I'm trying to derive an expression for the magnitude of \$ \frac{V_{out}}{V_{in}} \$ for this circuit from Razavi. I know that \$ \frac{V_{out}}{V_{in}} = \frac{V_{out}}{V_{X}} * \frac{V_{X}}{V_{in}} \...
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2answers
72 views

Problem with op amp output hitting bottom rail on output stage for DIY 3D printed strain gauge. High gain is needed

So the goal is to take our differential input from our experimental full bridge strain gauge and amplify the signal to a gain of roughly 5500. The output signal would then be going into a 12-bit ADC ...
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3answers
197 views

single supply op amp non inverting level shifter for NTSC signal processing from 0-0.7Vpp to 2-2.5Vpp

I am performing an RGB modding of an NTSC CRT TV. By performing tests I found out that the chroma chip will accept 2-2.5V Vpp RGB signal to get the proper colors. So I need to amplify and shift my ...
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1answer
57 views

What is the output of a cascaded amplifier?

I wanted to make an comparator with cascade of amplifiers of equal gain, output impedance etc. We know that we can approximate it as single pole system , thus a resistor and a capacitor in the output ...
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1answer
156 views

Audio Amplifier With MOSFET

I am working on a new project that seeks to implement a three-stage audio amplifier. One of my stages consists of a CASCODE circuit using the BF998 NMOS transistor. For this stage I am struggling to ...
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68 views

Maximum Current Gain Possible for a 100 mA PNP transistor

I have a pulse charging circuit where the maximum current is limited by the hFE of the PNP transistor (DTA144EE). The typical hFE at room temperature is ~220 as shown in the plot below. There is of ...
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2answers
285 views

What is the physical significance of beta and alpha in BJT?

I have read in the book that beta is the ratio of collector current to the base current in common emitter configuration and alpha is the ratio of collector current to emitter current to common base ...
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2answers
123 views

How to increase the voltage gain in a Class AB Transistor

I have the following circuit design of a Class AB Amplifier which amplifies the input voltage with a voltage gain of around 42. However, I'm wanting to increase that gain to around 80. Does anyone ...
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4answers
187 views

Why use gains on an ADC

Why do some people use some sort of gain either external amps or the one built in to the ADC itself and not just do the calculation in software. I do not think its that expensive of a processing power ...
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0answers
80 views

LM13700 Gain Calculation

I pulled some LM13700 OTAs from an old board and tested them. All voltages, currents, and resistances were measured. I had the expected (approximate) voltage gain using the equation \$ A=(R_2/(R_1+R_2 ...
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46 views

Two lock in amplifiers, almost identical setup, different AC Gain?

I am measuring a voltage output of around ~110 uV for two thermometers. Other than the placement of the thermometers on the sample and the frequency of the lock ins (7225 DSP at 11.137 Hz, 13.373 Hz), ...
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498 views

Is a resistor trimmer a good idea for adjusting the gain of an op amp circuit?

I'm designing this circuit to measure temperature with PT100. R10 must be calibrated to obtain the desired gain. I have thought of using a resistor trimmer to adjust the gain similar to the following:...
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1answer
44 views

AMC1200BDUBR Gain is 4 instead of 8

I want to measure grid voltage with AMC1200b. I used a resistor voltage divider and I lowered grid voltage from 110v(rms) to 110mv(rms). I fed the 110mv(rms) signal to AMC1200b (for the first side of ...
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Is there a programmable variable resistor

I have a current signal that can vary in amplitude. I currently have a transresistance amplifier which uses 330 Ohm resistors. However the amplitude of this signal can vary and I would like to be able ...
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84 views

Voltage gain from AC

Voltage gain CE & CC from AC Can you tell me please if I am true in calculation of gain of this circuit? Assumption: gm is known and beta=inf, Early VA=inf => gbe=0, gce=0. Here the Matlab code : <...
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2answers
63 views

Constancy of gain bandwidth product for amplifiers

I've seen the assumption of gain-bandwidth product being constant for some amplifiers. More specifically for a compensated op-amp. Is there any mathematical proof to establish why the product is ...
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1answer
51 views

Voltage gain from the Amplifier input to the load

I don't understand where the solution for part C coming from. What I thought is also Vo/Vi. I found Vo as 303 mV and Vi as Vs*(10/10+100). However in solution it seems my thought is wrong. How should ...
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623 views

Do we always take the corner frequency of a filter at exactly -3dB?

I'm doing some work on filters, but all the references I can find use a 'perfect' gain characteristic, with the trace starting at 0dB. Is the measurement for corner/cutoff frequency always taken at ...

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