# What is the definition of Cutoff Frequency?

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Cutoff frequency is generally used in the physics and electrical engineering fields. It is also known as corner or break frequency. This frequency is responsible for making a device to cease functioning in a proficient way, leading it to discontinue or shut down. Theoretically, the cutoff frequency decreases the energy flow through the device and obstructs it from working as intended. So, inadequate power stops the device from functioning proficiently.

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### What does Cut-off frequency behaves in Electronics?

A cutoff frequency is a border in a system's frequency response at which energy flowing through the system starts to decrease or reflected without being transmitted. Frequency response is the measure of any system's output spectrum in response to an input signal. In electronics, cutoff frequency is the frequency either above or below which the power output of a circuit, such as a line, amplifier, or electronic filter has dropped to a given amount of the power in the pass band, which is the range of frequencies or wavelengths that can pass through a filter without being reduced. In electronic systems such as filters, a device that removes from a signal some unwanted component or feature and in communication channels, which is a physical transmission medium such as a wire, cutoff frequency will behave in such a way that in

•  a low pass - a filter that passes low-frequency signals but reduces the amplitude of signals with frequencies higher than the cutoff frequency,
•  a high pass - filter that transmits high frequencies well but reduces the frequencies lower than the filter's cutoff frequency,
•  a band pass - a device that passes frequencies within a certain range and rejects frequencies outside that range, or
•  a band-stop - a filter that passes most frequencies unaltered, but reduces those in a specific range to very low levels.

### How is cut-off frequency defined?

The cutoff frequency is defined as the frequency at which the ratio of the (input/output) has a magnitude of 0.707. When this magnitude is changed to decibels –3dB mostly referred to as the 3dB down point. The cutoff frequency is characteristic of filtering devices, such as RC circuits. At this point, the quantity of attenuation due to the filter starts to amplify quickly.

### How does cut-off frequency behave in communication field?

Cutoff frequency is commonly used in the communications field. The process is noticed all over, in several ranges of frequencies. The resulting transmissions will be weak and typically unfeasible, if a given frequency is not within the optimal range to transmit and receive the signals. In communications, the phrase cutoff frequency makes us understand that the frequency lower than which a radio wave fails to go through a layer of the ionosphere at the incidence angle needed for transmission across two particular points by reflection from the layer. A common example of this is the now obsolete TV antenna. The picture and audio qualities were irregular and feeble, when a transmission was at a frequency outside of the most favorable range of the TV’s antenna. The cutoff frequency’s range is decreased and the reception is enhanced, by altering the antenna’s frequency range to offer room for a broad bandwidth. At the time, when the cutoff frequency threshold is exceeded on other devices, they just stop functioning. Albeit, the device gets sufficient energy, it will not be sufficient for the functioning and for making the device energetic. A lot of efforts are being taken to reduce several problems due to the lack of defined transmission standards in the modern era. Many nations espouse the identical frequency ranges for communications broadcast in an attempt to give a degree of consistency to radio, TV, and other broadcast signals. Consequently, these frequency bands can be modified to have their own cutoff frequencies exist in the above and below the bandwidth.

### What is the cut-off frequency of Waveguides?

The cutoff frequency of an electromagnetic waveguide is the lowest frequency for which a form will disseminate in it. Generally, in fiber optics, it is natural to believe the cutoff wavelength, which is the maximum wavelength that will spread in an optical fiber or waveguide. An optical fiber is a thin, flexible, transparent fiber that acts as a waveguide, or "light pipe", to transmit light between the two ends of the fiber. Consequently, any exciting frequency less than the cutoff frequency rather than propagating, will attenuate, that is decrease.

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