Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

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.

In electrical engineering, cutoff frequency or corner frequency is the frequency either above or below which the power output of a circuit, such as a line, amplifier, or electronic filter has fallen or risen to a given proportion of the power in the passband. Most frequently this proportion is half the passband power, also referred to as the 3 dB point since a fall of 3 dB corresponds approximately to half power.

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How do I calculate the cutoff frequency of a low pass rc circuit?

I want to calculate the cutoff frequency for a specific filter, but I can't find any formula for that. I know the formula for the cutoff frequency of a low pass filter: $$f_c=\frac{1}{2\pi RC}$$ But how is that derived in the first place? I don't…
rablentain
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Why do microwave ovens use magnetrons?

With a lot of advancement in solid state electronics and signal manipulation, isn't it easier to simply take high amplitude signals with frequencies near 1 MHz and multiply the signals using diodes and frequency filters(LC/RLC) than to use a…
Vishwa Mithra Tatta
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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 calculated as \$ \sqrt{\frac{R}{L}}\$, but I am asking why…
Binary Yildirim
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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 cut off frequency by…
awwew
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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. It works great, but my choice of component…
Jeremiah Rose
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Deriving 2nd order passive low pass filter cutoff frequency

I'm working on a 2nd order passive low pass filter, consisting of two passive low pass filters chained together. simulate this circuit – Schematic created using CircuitLab Let \$ H(s) = H_1(s)H_2(s) \$ where \$ H_1(s) \$ and \$ H_2(s) \$ are the…
ACarter
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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 exactly -3dB? What if the maximum gain isn’t…
TinyTitan
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Why do current transformers have a minimum frequency rating?

Datasheets of current transformers usually specify a working frequency range. In other words, they specify a minimum and maximum frequency for normal operation. I understand that the core losses grow exponentially with frequency. So the datasheets…
hkBattousai
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40 GHz spectrum analyzer with N-type coax input?

We have an old Rohde & Schwarz FSEK 30 that is advertised as having a range from 20 Hz to 40 GHz, with an N-type input connector. My conundrum is that a type-N connector with air dielectric should have a maximum frequency of approximately 19 GHz…
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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 strong injection regime, and that the…
Granger Obliviate
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How to find the cutoff frequency of an underdamped second order low pass filter?

I've learned that for a first order low pass filter (LPF) the 3 dB frequency is one where the amp's gain is (surprise) -3 dB below the DC gain. However, on a second order LPF that is underdamped we get a "peak" at around the cutoff frequency which…
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High pass filter - Cut-off frequency calculation doesn't match simulation

I have made the following simulation with the circuit you can see below: I'm asked to find the cut-off frequency for this filter. From the simulation, it looks like it \$f_c = 500 \text{Hz}\$ or somewhere around there. However, if I use the formula…
Carl
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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) = GBP / Av Slew Rate Frequency (f) = SR/(2*pi*Vp) Is…
Dhiraj Dhakal
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Region of Operation of MOSFET and current cutoff frequency

The current cut-off frequency for a MOSFET is defined as the frequency at which current gain (ratio of drain to source and gate to source current) is unity. Can we use MOSFET as an amplifier at frequencies higher than current cutoff frequency? If…
sarthak
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What is the purpose of this simple 1 capacitor 2 resistor high pass filter?

I have seen the standard high pass filter with the -3dB cutoff frequency = \$ 1/2\pi RC\$. simulate this circuit – Schematic created using CircuitLab However I have seen this particular circuit which I'm seeing here and there, especially on the…
midnightBlue
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