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  2. Orders of magnitude (frequency) - Wikipedia

    en.wikipedia.org/wiki/Orders_of_magnitude...

    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: Acoustic – the lowest possible frequency that a human can hear [3] 18 Hz: Average house cat's purr 24 Hz: Common frame rate of movies 27.5 Hz

  3. 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.

  4. 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 ]

  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

    Today most 60 Hz systems deliver nominal 120/240 V, and most 50 Hz nominally 230 V. The significant exceptions are in Brazil, which has a synchronized 60 Hz grid with both 127 V and 220 V as standard voltages in different regions, [20] and Japan, which has two frequencies: 50 Hz for East Japan and 60 Hz for West Japan.

  7. Mains electricity by country - Wikipedia

    en.wikipedia.org/wiki/Mains_electricity_by_country

    120 V 208 V 60 Hz Bahrain: G 230 V 400 V 50 Hz Bangladesh: A, C, D, G 220 V 380 V 50 Hz Barbados: A, B 115 V 200 V 50 Hz Belarus: C, F 230 V [10] 400 V 50 Hz Belgium: C, E NBN C 61 112-1: 230 V 230/400 V 50 Hz Belize: A, B, G 110 V 220 V 190 V 380 V 60 Hz Benin: C, E 220 V 380 V 50 Hz Bermuda: A, B 120 V 208 V 60 Hz Bhutan

  8. Audio frequency - Wikipedia

    en.wikipedia.org/wiki/Audio_frequency

    The SI unit of frequency is the hertz (Hz). It is the property of sound that most determines pitch. [1] The generally accepted standard hearing range for humans is 20 to 20,000 Hz. [2] [3] [4] In air at atmospheric pressure, these represent sound waves with wavelengths of 17 metres (56 ft) to 1.7 centimetres (0.67 in).

  9. Mains hum - Wikipedia

    en.wikipedia.org/wiki/Mains_hum

    Mains hum, electric hum, cycle hum, or power line hum is a sound associated with alternating current which is twice the frequency of the mains electricity.The fundamental frequency of this sound is usually double that of fundamental 50/60 Hz, i.e., 100/120 Hz, depending on the local power-line frequency.