What is Cutoff frequency: Definition and 17 Discussions

In physics and electrical engineering, a cutoff frequency, corner frequency, or break frequency is a boundary in a system's frequency response at which energy flowing through the system begins to be reduced (attenuated or reflected) rather than passing through.
Typically in electronic systems such as filters and communication channels, cutoff frequency applies to an edge in a lowpass, highpass, bandpass, or band-stop characteristic – a frequency characterizing a boundary between a passband and a stopband. It is sometimes taken to be the point in the filter response where a transition band and passband meet, for example, as defined by a half-power point (a frequency for which the output of the circuit is −3 dB of the nominal passband value). Alternatively, a stopband corner frequency may be specified as a point where a transition band and a stopband meet: a frequency for which the attenuation is larger than the required stopband attenuation, which for example may be 30 dB or 100 dB.
In the case of a waveguide or an antenna, the cutoff frequencies correspond to the lower and upper cutoff wavelengths.

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  1. I

    Cutoff frequency for this RLC circuit

    How would i find the cut of frequency of this RLC circuit .I have used LTspice to find it but what is the equation for finding it
  2. tworitdash

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  3. D

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  4. W

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  5. Y

    Derivation of cutoff frequency for RC circuit?

    How is it derived? The cutoff frequency is Fc = 1/2piRC. R = resistance, C = capacitance. I read somewhere it has to do with Laplace Transforms, but I'm not sure where to go from here. It kind of irks me to just accept this equation without some proof. Thanks!
  6. S

    Maximum (cutoff) freq for a photoresistor

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  7. P

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  8. B

    Cutoff frequency in this circuit

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  9. M

    Low-pass LC butterworth filter cutoff frequency question

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  10. H

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  11. P

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  12. C

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  13. L

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  14. C

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  15. E

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  16. L

    Bremsstrahlung near the cutoff frequency, experimental data

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  17. B

    Help Needed: Low Pass Filter Cutoff Frequency Closest to 100 kHz

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