# 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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### Switching voltage divider and low pass filter combined

I have an input signal which I want to switch from 12V-5V and a low pass filter directly after that, the issue is, if there wasn't a switch I can calculate the cut-off frequency easily. In my case, ...
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### Why is there a shift in cutoff frequencies of filters, and how to fix it?

I am doing a project where I am designing my own EEG circuit. I aim to keep it fairly simple and essentially design my circuit to do two things: Amplification Filtering I want to design the circuit (...
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### Charge Amplifier not amplifying at most frequencies

I have a piezoelectric element, which acts as an accelerometer. Attached to it is a charge amplifier, built based on this documentation. The op-amp is the TL081. The PZT element is simulated based on ...
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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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### Second-order Butterworth gain calculation at cut-off frequency

The Butterworth second-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's attenuation is -3 ...
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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 ...
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1 vote
139 views

### 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 ...
179 views

### 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.
1 vote
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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 ...
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1 vote
643 views

### 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. ...
• 87
265 views

### 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 ...
• 407
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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 ...
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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 ...
55 views

### 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 ...
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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?
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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-...
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830 views

### 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 ...
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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 ...
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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 ...
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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?
535 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 ...
885 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 ...
146 views

### 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 ...
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1 vote
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### 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 ...
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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}_\...
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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 ...
1 vote