Questions tagged [cutoff-frequency]
A cutoff frequency is a frequency boundary in a system's frequency response at which the power level is greater or less than a given fixed value.
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Signal Attenuation TVS and series resistor
This question is in regards to signal attenuation on high speed data lines like RS-485 (and any others as well). I'm new to the signal world, so please bear with me here.
Are there some useful ...
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1answer
78 views
Common mode choke parameters CAN circuitry, Split termination concept
1)I am trying to the understand the important parameters of a common mode choke that will be placed at the CANL and CANH lines of a transceiver.First parameter - Impedance as function of frequency - I'...
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3answers
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(Lack of) Miller Effect in Cascode considering Common Emitter and Common Base Seperately
I'm currently working on an analysis of a standard Cascode circuit, in particular why the frequency response is so good as it reduces the miller effect.
I have had a very vague explanation given to ...
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3answers
58 views
Skewed frequency response of RLC circuit
I built a simple RLC circuit:
I'm using a signal generator as input, and I'm reading the voltage across the capacitor with an oscilloscope.
I've calculated that the resonant frequency (where I will ...
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1answer
41 views
What happens to the low cut off frequency when replaced with a larger bypass capacitor?
When the emitter capacitance is increased to 100 microfarads. What would happen to the low frequency cut off of this amplifier?
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2answers
445 views
Second Order Passive RC Low Pass Filter Doesn't Have -6dB at cutoff Frequency in LTSpice
For Second-Order RC filter the cutoff frequency is: $$fc = \frac{1}{2\pi \sqrt {R_1C_1R_2C_2}}$$
I have taken R1 = R2 = R = 1K Ohm and C1 = C2 = C= 0.1591 micro Farad. So the cutoff frequency comes ...
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1answer
64 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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2answers
54 views
Behavior of frequency in a sinusoidal circuit
My question is in regards to a circuit like this with a sinusoidal voltage source Vin. When I try to figure out the voltage ratio between Vin and Vout I get ωCR/(ωCR - j). I then try to ...
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Scaling of magnetic field strength and flux density measurements and shape of hysteresis loop
Note: this is part of a larger question which I was asked to separate into subquestions.
Other subquestions: 1 and 2
I'm using the method outlined here to measure the induced magnetic flux density in ...
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0answers
30 views
Cutoff frequency of passive RC integrator used to measure magnetic flux density
Note: this is part of a larger question which I was asked to separate into subquestions.
Other subquestions: 1 and 2
I am using a passive RC integrator to measure the induced magnetic flux density in ...
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2answers
83 views
How to calculate cut-off frequency for T section high pass filter?
This is a high pass T filter:
According to me, if input voltage is \$V_{\text{in}}\$, then voltage across the inductor \$L\$ should be $$V_x=\frac{j\omega L}{j\omega L + \frac{1}{2j\omega C}}V_{\...
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determine the cutoff frequency of a nMOS in common gate with gate resistance
I have to determine the upper cutoff frequency of this circuit.
I absolutely mustn't use the laplace domain because it's too time consuming so not compatible with the time I have at the exam.
A rapid ...
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1answer
153 views
Common source amplifier, source degeneration and determining the cutoff frequency
I have a n-MOS transistor with the following biasing network:
I have to determine the cutoff frequency due to GS and GD capacitances
The method used by my book is to first redefine the ...
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3answers
313 views
How do we define the cutoff frequency in an active Op-Amp filter?
When we get a circuit such as the following:
How do we define the cut-off frequency? Is it still $$f_c = \frac1{2\pi R_1C_1}$$ since \$f_c\$ is defined for \$X_{c1} = R_1\$?
Or is it defined so that \...
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2answers
908 views
How to calculate amplifier gain (in dB) using frequency?
I know how to calculate decibel gain using the ratio of power, or Vin/Vout.
However, is there a way to calculate the magnitude of the attenuation and phase angle when you’re given the cutoff ...
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2answers
979 views
How to choose a cut-off frequency by interpreting FFT
I have a question concerning low pass filtering of IMU acceleration and gyro data. To choose a reasonable cut-off frequency, I thought about making some observations in the spectrum.
Now I have some ...
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54 views
Roll-off of a third-order active filter [duplicate]
I've a third order active filter, without zeros. I know that when \$f=0\$ the gain response is \$1\$. So the cutoff-frequency is located at:
$$\left|\text{H}\left(\omega_0\right)\right|=\frac{1}{\...
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Cut-off frequency calculation
Can anyone calculate the cut-off frequency and tell me which formula to be used on the Positive end of OPAMP?
what is the role of R1 here and R7 from the feedback?
Please answer in details with ...
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1answer
54 views
i want to know the cut off frequency on the 2 OPAMPS … Do I take 6K resistor and 5K resistor for OPAMP#2
I hope some one can check, I have a signal coming from a source and it goes in to 2 OPAMPS, and both has to be checked for cutoff frequencies...
I know 1/2*pi*RC is the formula but my question is how ...
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1answer
74 views
frequency response multistage
hello every one i need ask about frequency response i have an old question of our professor exam in few year, and i try to solve this question many time but i can't so please if any one have idea ...
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1answer
174 views
MOS Amplifier Circuit - Lower 3dB Frequency Calculation
I am confused with the above problem as the output node is not specified. If the output node is drain, it will be common source and if output is source, then it will be common drain.
My question is ...
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1answer
4k views
Derivation of cutoff frequency and phase shift for RC low pass filter
I've been having some problems with how to find the cutoff frequency and the phase shift for a simple RC low pass filter circuit. I've read this post, but I need a better understanding of what ...
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1answer
70 views
Which cut off frequency I should use in order to cancel AC noise with the low pass filter?
it may sound a bit stupid, but the thing is that I want to cancel the noise caused by AC frequencies in a circuit. I know I have to use a low pass filter, but which cut-off frequency should I use?
I'...
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6answers
430 views
Can a filter change the frequency of the input signal?
I am given a square wave with Vmin = 0V and Vmax=5V , T(period)=8ms and duty cycle 25%. I am asked to find the properties(low cutoff , high cutoff , bandwidth) of a band pass filter that will make the ...
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1answer
202 views
Calculating cutoff frequency of RCL circuit
Given is this circuit:
I know that:
$$G(j\omega)=\frac{\frac{1}{j\omega C}}{j\omega L+\frac{1}{j\omega C}+R}$$
But how do I calculate from this my cutoff frequency?
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1answer
942 views
Significance of cut-off frequency in a low-pass filter
My question is: why do we choose cut-off frequency to satisfy that the magnitude of transfer function \$ H(\omega) = \frac{1}{\sqrt{2}} \$?
Therefore I am not asking how cut-off frequency is ...
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2answers
148 views
Calculating the cut off frequency of a electronic filter
I've the following circuit:
I know that the transfer function is given by:
$$\mathscr{H}\left(\text{s}\right)=\frac{1}{1+sb_1+s^2b_2+s^3b_3}\tag1$$
Now, in this post they say that I can find the ...
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1answer
366 views
RC circuit and bessel filter finding the cutoff frequency
I've the following filer circuit and I want to know if my analysis is right.
simulate this circuit – Schematic created using CircuitLab
Using the transfer function of a series RC circuit:
$$\...
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2answers
571 views
20 Hz subsonic 350 W RC low pass filter
I build rotary subwoofers that produce ULF (subsonic) sound levels (youtube) .
The amplifier that I use is 12V 350W and supplies up to 25 amps.
I would like to create a reasonably high quality, ...
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2answers
920 views
High pass filter attenuating frequencies equal to cutoff frequency
I'm developing a HPF to attenuate frequencies below 30KHz.
My input voltage is a sinusoidal voltage from 0V to + 5V with a frequency of 30KHz.
My objective is to attenuate frequencies below 30KHz ...
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1answer
315 views
First order filter cut off frequency
Hi, I have been asked to estimate the half-power cutoff frequency of a first order filter that gave this response to a step input.
The problem I am having is I have only ever been given examples with ...
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1answer
607 views
UK Mains Frequency Limits
Question
Is there a maximum limit to mains frequency range that appliances will accept (e.g. if they conform to UK or EU standards?)
e.g. The Dynamic Demand web site indicates that there is a legal ...
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2answers
1k views
2nd order passive low pass filter cutoff frequency with additional paralel resistor before the second capacitor
How we can calculate the transfer function and cutoff frequency for this type of filter?
For second order low pass filter the natural frequency is:
$$
f_n = \frac{1}{2\pi \sqrt{R_1 R_2 C_1 C_2}}
$...
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1answer
98 views
how can I calculate the cutoff frequency for this low pass filter?
simulate this circuit – Schematic created using CircuitLab
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1answer
256 views
How is definition of cutoff frequency consistent with KVL?
Low pass and high pass \$RC\$ filters have a cutoff frequency that is equal to
$$f_c=\frac{1}{2\pi RC}$$
This should be the frequency at which the ratio \$|V_{out}/V_{in}|\$ is equal to \$1/\sqrt{2}\$....
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1answer
58 views
Determining value of capacitor, in a opamp ampifier circuit
I am working on the follwing circuit, and have found all values for the components, except for C3 which i have a hard time finding.
My requirements are that it should be able to handle 40-16k Hz with ...
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1answer
4k views
Low frequency response of a BJT amplifier.How is the cutoff frequency equal to \$ \frac{1}{2\pi (R_S+R_{in})C_{in}}\$ in fig 2
In a low frequency region of the single stage BJT amplifier, it is the
RC combinations formed by the capacitors \$ C_{in},C_E,C_{out}
\$ -Electronic Devices and Circuit Theory-Boylestad
...
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1answer
351 views
Bandpass Filter Attenuation?
I'm trying to split an audio signal into 5 channels, letting 5 different ranges through each filter (low, mids, highs, etc..). What I'm finding is that each bandpass filter has different levels of ...
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1answer
105 views
Decreasing of \$V_{in}\$ in a high pass filter due to the type of capacitor used
I observed a strange fact while using a simple RC high pass filter. Here is the circuit I used.
On \$CH1\$ I measured \$V_{out}\$, while on \$CH2\$ I observed the value of \$V_{in}\$.
I kept the ...
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5answers
760 views
Are slew rate frequency and cut off frequency same?
I am bit confused about the cut off frequency and the max frequency above which the output response starts to distort which is slew rate frequency. Are these two things same?
Cutoff frequency (f) = ...
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3answers
3k views
Divider and lowpass combined
I am using the following circuit for two purposes:
As a voltage divider, to reduce DC sensor output to a range suitable for my ADC.
As a lowpass filter, to remove high frequency noise from the signal....
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1answer
65 views
How to find cutoff freqency with more than one resistor
I have the above circuit and I want to find the cutoff frequency. Z_eff,in is my load. I have created a transfer function:
How is it possible to find the cutoff frequency? Let me know if more ...
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3answers
568 views
Steps to hand draw Bode magnitude plot for a particular transfer function
Can anyone guide me through how to hand draw a correct Bode magnitude plot for
$$G(s) = \dfrac{48000}{s(s+0.1)(s+100)}$$
Don't even need phase plot, just need correct magnitude plot
As few ...
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2answers
4k views
The Cutoff frequency of bandpass filter
Given:
Center Frequency f0 = 2.2KHz
Q factor = 5
The problem I'm facing is this: How do I calculate the 2 cutoff frequencies of this band pass filter? I'm confused because my question says "The ...
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3answers
798 views
Why is my amplifiers frequency response unexpected?
I am experimenting with moderately high frequency circuits, so decided to analyze, build and test an amplifier. This is the circuit:
Q1 is a CE amplifier, Q2 is Emitter follower to buffer the load. ...
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1answer
51 views
Total capacitance at output of source follower
This is the voltage gain of source follower at high frequency.
What I am confused here is why Cdb1, Cdg1 are not included in the pole of the transfer function?
Should it be Cgs2 + Csb2 + CL + Cdb1 +...
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0answers
133 views
A question on thevenizing an RC network
Sometimes when encountering an opamp or comparator input I see an RC network topology similar to the following one:
And in this case let's say we know everything but the value of C2, and we want to ...
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1answer
309 views
A question on adding noise and low-pass filer in Ltspice
I’m planning to implement the following Schmitt-trigger circuit:
(left-click to enlarge)
I made some updates with the great suggestions of jonk in my previous question:Some questions on optimizing a ...
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0answers
625 views
Open/Short Circuit Time Constant Appx. for Zero/Pole Analysis
3-dB corner frequency for poles and zeros can be approximated using open/short time constant method as described here: http://paginas.fe.up.pt/~fff/eBook/MDA/Met_con_tem.html
This method is used in ...
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1answer
265 views
Confusion with cut-off frequency calculation using Thevenin equivalent of an RC low pass filter
When I was trying to see the effect of load at the output of an RC low-pass filer I found myself in some sort of confusion. Below is an RC low-pass filter circuit with another R as a load and its ...
