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  2. Utility frequency - Wikipedia

    en.wikipedia.org/wiki/Utility_frequency

    The waveform of 230 V and 50 Hz compared with 120 V and 60 Hz. The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user.

  3. Hertz - Wikipedia

    en.wikipedia.org/wiki/Hertz

    The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. [1] [a] The hertz is an SI derived unit whose formal expression in terms of SI base units is s −1, meaning that one hertz is one per second or the reciprocal of one second. [2]

  4. Orders of magnitude (frequency) - Wikipedia

    en.wikipedia.org/.../Orders_of_magnitude_(frequency)

    1 hertz (Hz) 1 to 1.66 Hz: Approximate frequency of an adult human's resting heart beat: 1 Hz: 60 bpm, common tempo in music 2 Hz: 120 bpm, common tempo in music ~7.83 Hz: Fundamental frequency of the Schumann resonances: 10 1: 10 hertz 10 Hz: Cyclic rate of a typical automobile engine at idle (equivalent to 600 rpm) 12 Hz

  5. Frequency - Wikipedia

    en.wikipedia.org/wiki/Frequency

    Frequency (symbol f), most often measured in hertz (symbol: Hz), is the number of occurrences of a repeating event per unit of time. [1] It is also occasionally referred to as temporal frequency for clarity and to distinguish it from spatial frequency .

  6. Mains electricity - Wikipedia

    en.wikipedia.org/wiki/Mains_electricity

    A 50 Hz ±5 Hz vibrating-reed mains frequency meter for 220 V The world's first public electricity supply was a water wheel driven system constructed in the small English town of Godalming in 1881. It was an alternating current (AC) system using a Siemens alternator supplying power for both street lights and consumers at two voltages, 250 V for ...

  7. Electromagnetic spectrum - Wikipedia

    en.wikipedia.org/wiki/Electromagnetic_spectrum

    Frequencies observed in astronomy range from 2.4 × 10 23 Hz (1 GeV gamma rays) down to the local plasma frequency of the ionized interstellar medium (~1 kHz). Wavelength is inversely proportional to the wave frequency, [ 1 ] so gamma rays have very short wavelengths that are fractions of the size of atoms , whereas wavelengths on the opposite ...

  8. Radio frequency - Wikipedia

    en.wikipedia.org/wiki/Radio_frequency

    Radio frequency (RF) is the oscillation rate of an alternating electric current or voltage or of ... such as the 50 or 60 Hz current used in electrical power ...

  9. Harmonic - Wikipedia

    en.wikipedia.org/wiki/Harmonic

    For example, if the fundamental frequency is 50 Hz, a common AC power supply frequency, the frequencies of the first three higher harmonics are 100 Hz (2nd harmonic), 150 Hz (3rd harmonic), 200 Hz (4th harmonic) and any addition of waves with these frequencies is periodic at 50 Hz.