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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Equivalent resistance calculation to find lower cutoff frequency of the transistor

The cutoff frequency of the amplifier is $$ \omega_c=\frac{1}{Req*C} $$ which when evaluated gives $$ \omega_c=\frac{1}{(6k\Omega ||4k\Omega)*10nF}=41666.66 rad/s$$ The answer is $$ 10^4 rad/s $$ This ...
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2nd Order Butterworth gain calculation at cut off frequency

The Butterworth 2nd order Low-pass filter has the following transfer function: $$\frac{\omega_c^2}{s^2+\sqrt2s\omega_c+\omega_c^2}$$ We know that at \$s=\omega_c\$, the filter attenuation is -3dB, but ...
user97662's user avatar
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unfamiliar notch filter configuration [duplicate]

This is a configuration of the notch filter that I saw in some design. It is very different from the Active Twin-T notch filter configs that show up on a quick google search. Any idea what is going on ...
roaibrain's user avatar
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Getting the cutoff frequency

I want to know the cut off frequency of this circuit, given that the GBW is constant (1.9MHz) and R1=8.2kOhm and R2=114.6KOhm. I did 19e6/2*\$\pi\$*R2 (since it doesn't have a capacitor) but my ...
Patricia Vieira's user avatar
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Can we find out RLC Circuit values from just cut-off frequencies?

For example, I've passive BPF series RLC circuit with the information of lower and upper cut-off frequencies. I need to find out the values of R, L and C. Is it possible? Thanks in advance.
Patrem's user avatar
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Common Emitter small signal model for high frequencies simplification

While trying to calculate the high frequency pole frequency corner of the common emitter amplifier I came across the following small signal model (found here in page 332) The small signal equivalent ...
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My LTspice simulation results don't match the breadboard

I was testing a high pass filter like this. And here comes the simulation result on LTspice as well. This is the AC analysis result followed by the transient analysis. The 8Hz transient analysis ...
Tian's user avatar
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How can I calculate the cut-off frequency of an RC filter?

I tred to calculate the cut-off frequency of the circuit below. When I think of two resistors as parallel and calculate them in a built-in RC filter calculator, I found a 51.0112 Hz cut-off frequency. ...
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How to calculate the cut-off frequency of a software average filter

I want to read the voltage of a battery using an ADC connected to a PLC. The signal oscillates a bit and I want to smooth it. The ADC samples the signal at 860 samples per second and stores it in ...
bardulia's user avatar
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Understanding opamp circuit, 13 MHz (interference?) amplification

I have the circuit drawn below soldered to a prototyping board. First, I added a high-pass filter a with cutoff-frequency of 600 kHz, since I would like to receive around 2 MHz. Then the received ...
Mart's user avatar
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Second-order low-pass RC filter not working as expected

I am working on building a crossover filter for a set of speakers and I have started by designing a simple second-order RC low-pass filter on a breadboard. Assuming the circuit is wired correctly (I ...
Jake Slavin's user avatar
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Issues associated with a single layer PCB for an RLC band pass filter

I have an issue the design of an RLC band pass filter with bandwidth ranging from 5kHz to 15 kHz. I simulated the given circuit in Proteus. It worked perfectly fine there. I then tested it on a ...
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Phil's lab understanding how to choose a ferrite bead

I'm trying to understand what ferrite bead he chose as shown in the picture. It says it is a 120R ferrite bead but from what I understand, when looking for a ferrite bead, you have to know the ...
elec's user avatar
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Confusion regarding bode plot?

I am trying to understand bode plot and i came across attached snap especially black solid line in magnitude plot, i captured this snap from wikipedia. Here i am confused,what is cutt off frequency? ...
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DAC MCP4802 datasheet corner frequency

The MCP4802 8bit DAC datasheet states that (1/f) CORNER = 400 Hz. Does it mean that even if I input to DAC 1kHz (using Arduino Nano) signal it will be attenuated due to the 400Hz cutoff of the DAC?
ojacomarket's user avatar
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About calculating the RHP zeros frequency in case of PSFB and Buck converter

Currently I am doing the regulation of a PSFB converter in CCM. I have reached the phase of dimensioning the parameters of a PI corrector (Kp and Ki). To do this, I need to choose the value of the cut-...
Rim's user avatar
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Finding resonant frequency and cut-off frequency from Bode plot to calculate values for RLC circuit

I am trying to find RLC values from a Bode plot. I have a band-pass filter from a transfer function and have put arbitrary values for the RLC components in Matlab. I am unsure how to mathematically ...
meak21's user avatar
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How to compute the cutoff frequency of a bandpass audio filter?

Much like the title says, I'm wondering how one would compute the cutoff frequency of a bandpass filter given the filter's specs, rather than the usual resistance and capacitance. In other words, how ...
Anthony K's user avatar
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Adjustable low-pass filter with logarithmic cut-off control via potentiometer

Let's consider this simple RC low-pass filter: We can make the cut-off frequency adjustable by replacing \$R\$ with a potentiometer. But then the cut-off frequency \$f\$ is proportional to \$\frac{1}{...
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Powers of 10 in cutoff frequency formula for capacitor

I need to know which values in this formula should have some powers of 10 applied. I'm using the formula: Fc = 1 / (2π R C) to find the capacitor value needed in-line to cut low frequencies from a ...
Scott K's user avatar
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Band-pass filter simulation

Passive band-pass filter simulation on LTspice. Given: cutoff frequencies Flow= 10 kHz and Fhigh= 22 kHz. The run isn't getting me -3 dB between the pass. I calculated R and C and put them in the ...
Jessie Raya's user avatar
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Waveform acquired from scope, what is the sample rate for post processing?

I want to make a noise measurement with my scope, but I need it to be band-limited. I am using a Tektronix TBS1102, which allows me to save to a USB flash drive an Excel/CSV file with the X and Y ...
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Parallel-series RC circuit

I wanted to calculate frequencies of filter The module of impedance which I got is equal What is the frequency cutoff of this circuit? I've made a simulation but I wanted to get frequency cutoff.
Malum Wolfram's user avatar
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Why is the relation between voltage ratio and frequency a linear one in a lumped transition line?

In an experiment the cutoff frequency of a lumped transmission line is determined by measuring the ratio of the output/input voltages. The lumped transmission line is a ladder network of 40 capacitors ...
Chern-Simons's user avatar
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1 answer
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Simulating an RLC bandpass filter with LTspice

I have analyzed the filter in question both in practice and in simulation (with LTspice) The calculations I performed to determine the high and low cutoff frequency and the resonance frequency are as ...
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Frequency response of low pass filter

I have an ideal low pass filter having cutoff frequency 1kHz. If I provide an input having single frequency component at 1kHz, will there be any output or zero?
Abhishek's user avatar
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Filter for AC line coupling with audio signal source

I need a sharp notch filter (higher order) for the 50-60 Hz band, to be placed between AC 220/125 V power line and an audio source (not necessarily amplified), such that the input signal from the ...
FoSoFix's user avatar
1 vote
1 answer
103 views

The field in a waveguide at exactly the cut-off frequency

Can anyone explain to me qualitatively, what kind of field exists inside a waveguide at EXACTLY the cut-off frequency? I would be grateful if an explanation was given about waveguides with metalic ...
Minas Michael Opethian's user avatar
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1 answer
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I want to find the corner frequency of this second order low pass filter

As there is an isolator an between, I have tried multiplying the individual transfer functions to get the combined function and then equated it with -3dB.
pvk's user avatar
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Can an ADXL327 accelerometer be used with theoretically unlimited bandwidth?

I saw several studies that use the 3-axis ADXL327 accelerometer, 0.1-3000 Hz band-pass filtered and sampled at 20KHz based on previous studies that showed that the signals of interest have frequencies ...
Hattori's user avatar
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1 answer
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Why is the noise gain these opamps 500? I feel it should be 250

I wanted to check the bandwidth of the first stage of an instrumentation amplifier configuration and this is the circuit: Since, the noise gain of an opamp is (1+Rf/R1), for each of the op-amps the ...
needbrainscratched's user avatar
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1 answer
549 views

Cut Off Frequency in the Frequency Response of RC circuit

In the frequency response curve of RC circuit, why does the curve falls rapidly after the breakpoint? It approximates to a certain amplitude upto the breakpoint. In the diagram, given below, it is ...
Pooja Agarwal's user avatar
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1 answer
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Cutoff frequency of RLC band pass and band stop filter

I have found in a website that the cutoff frequencies of a series RLC bandpass and bandstop filters are: $$ f_c = \sqrt{\left(\frac{R}{2L}\right)^2+\frac{1}{LC}}\pm\frac{R}{2L}. $$ This is the link ...
Jun Seo-He's user avatar
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1 answer
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About the cut off frequency

I am doing a work that basically we need to study the graphs given by an oscilloscope, and with it, find the cut off frequency of the circuit that better approach the data given by the oscilloscope (...
LSS's user avatar
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4 answers
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Frequency response of difference amplifier

I'm studying the difference amplifier circuit configuration of op amps, reading from this datasheet. I know that unlike the instrumentation amplifiers, the difference amplifier differential gain can ...
Brad's user avatar
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1 vote
1 answer
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Calculating the cut-off frequency

I have an inverter opamp with the next data : \$A=-25\$ \$A_{ol}=20\frac{mV}{V}\$ Unity Gain Bandwith\$=10^{6}\$ Then asks for the cutt off frequency, so the open loop its passed to db \$20\,\frac{V}...
avelardo's user avatar
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3 answers
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How can I find the cutoff-frequency in real experiment?

My Problem is that I can't figure out how to answer this question: The component values in the previous measurements have been known and the cut-off frequency could be calculated. In real life, this ...
hong's user avatar
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1 vote
3 answers
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Signal is always attenuated by passive bandpass filter

I'm trying to build a passive bandpass filter with the cutoff frequencies of 0.001 Hz and 10 Hz. It seems that my signal is always attenuated. Why?
Sara Martins's user avatar
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1 answer
479 views

Active low pass filter with cut-off frequency ~4250 Hz lets a 20 kHz signal through

I needed an active low pass filter for my project that can produce an output voltage within the required settling time and ripple voltage ranges. Although I managed to get a good enough output voltage ...
Curious Student's user avatar
6 votes
2 answers
818 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 ...
TinyTitan's user avatar
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1 answer
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Manually calculated -3dB cut off frequency differs from the simulated value

I have been trying to do experiments with a differential BJT pair. As the output resistance for the common emitter configuration is R_c (1k), instead of finding the capacitance, I attached a 1pF ...
Hari Krishna's user avatar
1 vote
1 answer
451 views

Capacitive voltage divider frequency response and cut-off frequency

I'm working on designing a guitar pedal based on the topology of an old tube amplifier I own. Between the amplification stages I found an inter-stage filter that I cannot understand in the frequency ...
EdoG's user avatar
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Finding the cut-off frequency of a filter

For a general filter, what is the way to find the cut-off frequency? In this link Okawa Electronic Design shows a formula for the cut-off frequency of a Sallen-key filter that looks like: $$\text{f}_\...
Jan Eerland's user avatar
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Cut-off frequency in simulation does not match calculation

I am an engineering student currently learning how to design low-pass active filters. Currently, I am having trouble matching my calculations with the simulation values. My design has the following ...
Guorishix's user avatar
1 vote
2 answers
543 views

Second Order Butterworth LPF Cut-off frequency determining from graph

I am trying to design a butterworth low pass filter with corner frequency at 2khz as seen below. And my problem is when I find its transfer function It is as follows: \$H(s)=\dfrac{1}{1+1.414\times (\...
Nabla's user avatar
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Bandwidth of low pass filter: measured with the cut-off frequency?

I have the following Sallen & Key lowpass filter: $$T(s)=\frac{\frac{1}{R_1R_2C_1C_2}}{s^2+(\frac{1}{C_1R_1}+\frac{1}{C_1R_2})s+\frac{1}{R_1R_2C_1C_2}}$$ The parameters values are \$R_1=10 k\...
Granger Obliviate's user avatar
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1 answer
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Setting the cutoff frequency of an active bandpass filter (op amp) and finding the phase in LTSpice

I am doing an exercise and my op amp cutoff frequencies are: lower 1kHz, upper 10kHz. I have found the phase shift of the filter, but since the graph I get does not make much sense for me I think it ...
Igor Smorąg's user avatar
4 votes
1 answer
438 views

Cut-off frequency of a LED

I'm trying to solve this problem: A GaAs LED is at \$ 300 K \$ when the current density is 1000 \$A/cm^2\$ . The width of the active region is \$ 1 µm \$. Assume that, for that current, we are in the ...
Granger Obliviate's user avatar
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2 answers
313 views

Sallen-Key Low Pass filter

I was trying to do a project on LT spice for the frequency response for Sallen-Key low Pass filter. But when I tried the Following circuit, I am getting a roll off 20db / decade instead of 40db/decade....
Aryan's user avatar
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2 votes
1 answer
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Finding upper cutoff and lower cutoff frequencies on notch circuit

I need to find upper cutoff (UCF) and lower cutoff (LCF) frequencies based on formulas of a notch circuit, but I'm getting a quadratic equation (as expected) with an imaginary number (IN; not expected....
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