Share
VIDEOS 1 TO 50
528Hz | Repairs DNA & Brings Positive Transformation | Solfeggio Sleep Music
528Hz | Repairs DNA & Brings Positive Transformation | Solfeggio Sleep Music
Published: 2016/02/19
Channel: Meditative Mind
432 Hz - Deep Healing Music for The Body & Soul - DNA Repair, Relaxation Music, Meditation Music
432 Hz - Deep Healing Music for The Body & Soul - DNA Repair, Relaxation Music, Meditation Music
Published: 2016/03/16
Channel: Meditation and Healing
432 Hz | Deep Sleep Calming (1 Hour) Meditation
432 Hz | Deep Sleep Calming (1 Hour) Meditation
Published: 2015/04/05
Channel: Infinite Waters (Diving Deep)
432 hz DNA Healing/Chakra Cleansing Meditation/Relaxation Music
432 hz DNA Healing/Chakra Cleansing Meditation/Relaxation Music
Published: 2014/09/04
Channel: One Mind
432Hz Miracle Tone - Raise Positive Vibrations | Healing Frequency 432hz | Positive Energy Boost
432Hz Miracle Tone - Raise Positive Vibrations | Healing Frequency 432hz | Positive Energy Boost
Published: 2016/10/17
Channel: PowerThoughts Meditation Club
20Hz to 20kHz (Human Audio Spectrum)
20Hz to 20kHz (Human Audio Spectrum)
Published: 2012/10/02
Channel: adminofthissite
963Hz | Pineal Gland Activation | Sleep Music | Solfeggio Sleep Meditation Music
963Hz | Pineal Gland Activation | Sleep Music | Solfeggio Sleep Meditation Music
Published: 2016/02/27
Channel: Meditative Mind
528Hz | Miracle Tone | 8 Hours
528Hz | Miracle Tone | 8 Hours
Published: 2015/05/12
Channel: Meditative Mind
432Hz | Healing Music | Derived from Cosmos | 8 HOURS
432Hz | Healing Music | Derived from Cosmos | 8 HOURS
Published: 2015/05/17
Channel: Meditative Mind
Franck-Hertz-Versuch einfach erklärt
Franck-Hertz-Versuch einfach erklärt
Published: 2015/05/05
Channel: TheSimplePhysics
HERTZ CAR AUDIO
HERTZ CAR AUDIO
Published: 2016/11/25
Channel: HERTZ AUDIO COLOMBIA
528 hz DNA Healing/Chakra Cleansing Meditation/Relaxation Music "Sounds of Nature"
528 hz DNA Healing/Chakra Cleansing Meditation/Relaxation Music "Sounds of Nature"
Published: 2015/02/19
Channel: One Mind
528Hz Frequência dos Milagres ➤ Limpeza de Energias Negativas e Frequência de Cura Pelo Amor - 9 Hrs
528Hz Frequência dos Milagres ➤ Limpeza de Energias Negativas e Frequência de Cura Pelo Amor - 9 Hrs
Published: 2016/09/14
Channel: Clube de Meditação para Pensamentos Poderosos
8 Hours Relaxing Music in 432 Hertz, Nature Sounds, Zen, Massage, Spa, Study, Background, Yoga
8 Hours Relaxing Music in 432 Hertz, Nature Sounds, Zen, Massage, Spa, Study, Background, Yoga
Published: 2015/09/03
Channel: Sebastien Zunino
Heinrich Hertz und die elektromagnetischen Welle Meilensteine
Heinrich Hertz und die elektromagnetischen Welle Meilensteine
Published: 2013/02/13
Channel: Lourdes Meinsen
Hertz and Radio Waves Explained
Hertz and Radio Waves Explained
Published: 2016/05/29
Channel: High School Physics Explained
VW Golf Apple Carplay AppRadio Lautsprecher Hertz HSK Hertz Endstufe
VW Golf Apple Carplay AppRadio Lautsprecher Hertz HSK Hertz Endstufe
Published: 2016/04/07
Channel: Kai Stüven
Замена ШТАТНОЙ АКУСТИКЕ - Hertz Uno бюджетная акустика для замены штатки - обзор от Decibel
Замена ШТАТНОЙ АКУСТИКЕ - Hertz Uno бюджетная акустика для замены штатки - обзор от Decibel
Published: 2017/04/24
Channel: Decibel
Power By Hertz
Power By Hertz
Published: 2013/06/09
Channel: HERTZ AUDIO COLOMBIA
Técnica HERTZ® Reprogramação da Frequência Vibracional - criada por Elainne Ourives
Técnica HERTZ® Reprogramação da Frequência Vibracional - criada por Elainne Ourives
Published: 2016/12/14
Channel: Elainne Ourives
Hertz Experiment on Electromagnetic Waves
Hertz Experiment on Electromagnetic Waves
Published: 2015/02/28
Channel: Ludic Science
Hertz dsk 165.3 Opel tigra test.
Hertz dsk 165.3 Opel tigra test.
Published: 2014/04/06
Channel: cinek664
963 Hertz - Glândula Pineal - Ativação (1H) (HQ)
963 Hertz - Glândula Pineal - Ativação (1H) (HQ)
Published: 2016/04/30
Channel: DNA Astral
Pure Binaural Beats 8 Hertz Alpha Waves
Pure Binaural Beats 8 Hertz Alpha Waves
Published: 2013/01/27
Channel: The Brain Garage
Binaural Hertz - Frequência da Disposição
Binaural Hertz - Frequência da Disposição
Published: 2017/04/04
Channel: Elainne Ourives
Hertz Columbia - Martin Garrix Animals
Hertz Columbia - Martin Garrix Animals
Published: 2017/04/14
Channel: Ubharta Indian
Joe Hertz - Isolate feat. Kaleem Taylor
Joe Hertz - Isolate feat. Kaleem Taylor
Published: 2014/05/29
Channel: Majestic Casual
Binaural Hertz - Frequência da Alegria
Binaural Hertz - Frequência da Alegria
Published: 2017/04/04
Channel: Elainne Ourives
432 hertz, a frequencia que cura. durma. ouvindo baixinho!
432 hertz, a frequencia que cura. durma. ouvindo baixinho!
Published: 2014/08/20
Channel: Luiz Lindao
Hertz - Sound Cars Colombia
Hertz - Sound Cars Colombia
Published: 2016/11/27
Channel: Car Audio Tuning Show
Binaural Hertz - Frequência do Amor
Binaural Hertz - Frequência do Amor
Published: 2017/04/04
Channel: Elainne Ourives
Música em 432 hertz Favorecendo a Meditação, Estudo e Relaxamento
Música em 432 hertz Favorecendo a Meditação, Estudo e Relaxamento
Published: 2014/07/31
Channel: Liv Frei
TEAM HERTZ
TEAM HERTZ
Published: 2016/02/26
Channel: HERTZ CAR AUDIO
Frequência Hertz Quântico  - Vibrar Paz (600Hertz), Bem Estar, criado e voz Elainne Ourives
Frequência Hertz Quântico - Vibrar Paz (600Hertz), Bem Estar, criado e voz Elainne Ourives
Published: 2017/06/18
Channel: Elainne Ourives
Musica 528 hz A Frequencia do Amor - 1 hora de Musica Relaxante
Musica 528 hz A Frequencia do Amor - 1 hora de Musica Relaxante
Published: 2015/09/20
Channel: Relax Hall Português
Hertz 24/7: Vehicle instructions
Hertz 24/7: Vehicle instructions
Published: 2015/05/01
Channel: Hertz UK
Binaural Hertz - Frequência da Aceitação
Binaural Hertz - Frequência da Aceitação
Published: 2017/04/04
Channel: Elainne Ourives
Beethoven - Symphony N. 9 - COMPLETE - 432 Hz. (432 Hertz)
Beethoven - Symphony N. 9 - COMPLETE - 432 Hz. (432 Hertz)
Published: 2014/09/14
Channel: 432naturalpitch
Incredible! Schumann Resonance at 40 hertz - MAJOR frequency rise
Incredible! Schumann Resonance at 40 hertz - MAJOR frequency rise
Published: 2017/08/05
Channel: MrMBB333
Binaural Hertz - Frequência da Iluminação
Binaural Hertz - Frequência da Iluminação
Published: 2017/04/04
Channel: Elainne Ourives
528 Hertz - A Frequência do Milagre - Reparo do DNA (1H) (HQ)
528 Hertz - A Frequência do Milagre - Reparo do DNA (1H) (HQ)
Published: 2016/04/28
Channel: DNA Astral
Первый взгляд на акустику Hertz ESK 165.5 L (Unpacking)
Первый взгляд на акустику Hertz ESK 165.5 L (Unpacking)
Published: 2014/12/19
Channel: Decibel
Hertz - Las ondas electromagnéticas - Física
Hertz - Las ondas electromagnéticas - Física
Published: 2012/07/14
Channel: Moisés López Caeiro
Que son los Hertz y Frecuencias? | Car Audio
Que son los Hertz y Frecuencias? | Car Audio
Published: 2016/07/17
Channel: Extreme Bass Audio Car
El Experimento de Hertz : Ondas Electromagnéticas
El Experimento de Hertz : Ondas Electromagnéticas
Published: 2015/02/28
Channel: Manuel Rodriguez-Achach
Técnica Hertz®REPROGRAMAÇÃO DA FREQUÊNCIA VIBRACIONAL PARA FINANCEIRO
Técnica Hertz®REPROGRAMAÇÃO DA FREQUÊNCIA VIBRACIONAL PARA FINANCEIRO
Published: 2016/10/17
Channel: Elainne Ourives
Perdere peso e guadagnare decibel con Hertz Audio - Davide Cironi Drive Experience (ENG.SUBS)
Perdere peso e guadagnare decibel con Hertz Audio - Davide Cironi Drive Experience (ENG.SUBS)
Published: 2017/07/20
Channel: Davide Cironi
Experimento de Hertz, ondas electromagnéticas Radiofrecuencia
Experimento de Hertz, ondas electromagnéticas Radiofrecuencia
Published: 2015/10/04
Channel: Espacio de César
Joe Hertz - Stay Lost ft. Amber-Simone (Cabu Remix)
Joe Hertz - Stay Lost ft. Amber-Simone (Cabu Remix)
Published: 2016/04/17
Channel: Majestic Casual
Hertz Ultimate Choice®
Hertz Ultimate Choice®
Published: 2017/08/01
Channel: Hertz
NEXT
GO TO RESULTS [51 .. 100]

WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Hertz
Unit system SI derived unit
Unit of Frequency
Symbol Hz 
Named after Heinrich Hertz
In SI base units s−1
Top to bottom: Lights flashing at frequencies f = 0.5 Hz, 1.0 Hz and 2.0 Hz, i.e. at 0.5, 1.0 and 2.0 flashes per second, respectively. The time between each flash – the period T – is given by 1f (the reciprocal of f), i.e. 2, 1 and 0.5 seconds, respectively.

The hertz (symbol: Hz) is the derived unit of frequency in the International System of Units (SI) and is defined as one cycle per second.[1] It is named for Heinrich Rudolf Hertz, the first person to provide conclusive proof of the existence of electromagnetic waves. Hertz are commonly expressed in multiples: kilohertz (103 Hz, kHz), megahertz (106 Hz, MHz), gigahertz (109 Hz, GHz), and terahertz (1012 Hz, THz).

Some of the unit's most common uses are in the description of sine waves and musical tones, particularly those used in radio- and audio-related applications. It is also used to describe the speeds at which computers and other electronics are driven.

Definition[edit]

The hertz is equivalent to cycles per second, i.e., "1/second" or .[2] The International Committee for Weights and Measures defined the second as "the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom"[3] and then adds the obvious conclusion: "It follows that the hyperfine splitting in the ground state of the caesium 133 atom is exactly 9 192 631 770 hertz, ν(hfs Cs) = 9 192 631 770 Hz."

In English, "hertz" is also used as the plural form.[4] As an SI unit, Hz can be prefixed; commonly used multiples are kHz (kilohertz, 103 Hz), MHz (megahertz, 106 Hz), GHz (gigahertz, 109 Hz) and THz (terahertz, 1012 Hz). One hertz simply means "one cycle per second" (typically that which is being counted is a complete cycle); 100 Hz means "one hundred cycles per second", and so on. The unit may be applied to any periodic event—for example, a clock might be said to tick at 1 Hz, or a human heart might be said to beat at 1.2 Hz. The occurrence rate of aperiodic or stochastic events is expressed in reciprocal second or inverse second (1/s or s−1) in general or, in the specific case of radioactive decay, in becquerels.[5] Whereas 1 Hz is 1 cycle per second, 1 Bq is 1 aperiodic radionuclide event per second.

Even though angular velocity, angular frequency and the unit hertz all have the dimension 1/s, angular velocity and angular frequency are not expressed in hertz,[6] but rather in an appropriate angular unit such as radians per second. Thus a disc rotating at 60 revolutions per minute (rpm) is said to be rotating at either 2π rad/s or 1 Hz, where the former measures the angular velocity and the latter reflects the number of complete revolutions per second. The conversion between a frequency f measured in hertz and an angular velocity ω measured in radians per second is

and .

This SI unit is named after Heinrich Hertz. As with every International System of Units (SI) unit named for a person, the first letter of its symbol is upper case (Hz). However, when an SI unit is spelled out in English, it should always begin with a lower case letter (hertz)—except in a situation where any word in that position would be capitalized, such as at the beginning of a sentence or in material using title case. Note that "degree Celsius" conforms to this rule because the "d" is lowercase.— Based on The International System of Units, section 5.2.

History[edit]

The hertz is named after the German physicist Heinrich Hertz (1857–1894), who made important scientific contributions to the study of electromagnetism. The name was established by the International Electrotechnical Commission (IEC) in 1930.[7] It was adopted by the General Conference on Weights and Measures (CGPM) (Conférence générale des poids et mesures) in 1960, replacing the previous name for the unit, cycles per second (cps), along with its related multiples, primarily kilocycles per second (kc/s) and megacycles per second (Mc/s), and occasionally kilomegacycles per second (kMc/s). The term cycles per second was largely replaced by hertz by the 1970s. One hobby magazine, Electronics Illustrated, declared their intention to stick with the traditional kc., Mc., etc. units.[8]

Applications[edit]

A sine wave with varying frequency
A heartbeat is an example of a non-sinusoidal periodic phenomenon that may be analyzed in terms of frequency. Two cycles are illustrated.

Vibration[edit]

Sound is a traveling longitudinal wave which is an oscillation of pressure. Humans perceive frequency of sound waves as pitch. Each musical note corresponds to a particular frequency which can be measured in hertz. An infant's ear is able to perceive frequencies ranging from 20 Hz to 20,000 Hz; the average adult human can hear sounds between 20 Hz and 16,000 Hz.[9] The range of ultrasound, infrasound and other physical vibrations such as molecular and atomic vibrations extends from a few femtoHz[10] into the terahertz range[11] and beyond.

Electromagnetic radiation[edit]

Electromagnetic radiation is often described by its frequency—the number of oscillations of the perpendicular electric and magnetic fields per second—expressed in hertz.

Radio frequency radiation is usually measured in kilohertz (kHz), megahertz (MHz), or gigahertz (GHz). Light is electromagnetic radiation that is even higher in frequency, and has frequencies in the range of tens (infrared) to thousands (ultraviolet) of terahertz. Electromagnetic radiation with frequencies in the low terahertz range (intermediate between those of the highest normally usable radio frequencies and long-wave infrared light) is often called terahertz radiation. Even higher frequencies exist, such as that of gamma rays, which can be measured in exahertz. (For historical reasons, the frequencies of light and higher frequency electromagnetic radiation are more commonly specified in terms of their wavelengths or photon energies: for a more detailed treatment of this and the above frequency ranges, see electromagnetic spectrum.)

Computers[edit]

In computers, most central processing units (CPU) are labeled in terms of their clock rate expressed in megahertz or gigahertz (106 or 109 hertz, respectively). This number refers to the frequency of the CPU's master clock signal ("clock rate"). This signal is a square wave, which is an electrical voltage that switches between low and high values at regular intervals. Hertz has become the primary unit of measurement accepted by the general populace to determine the performance of a CPU, but many experts have criticized this approach, which they claim is an easily manipulable benchmark as some processors use multiple clock periods to perform a single operation, while others can perform multiple operations in a single cycle.[12] For home-based personal computers, CPU clock speeds have ranged from approximately 1 MHz in the late 1970s (Atari, Commodore, Apple computers) to up to 6 GHz in IBM POWER processors.

Various computer buses, such as the front-side bus connecting the CPU and northbridge, also operate at various frequencies in the megahertz range.

The "speed" or the more correct term bandwidth of networks, including wireless, such as Wi-Fi, 3G, 4G, LTE, etc. is not affected by the myth described above. In general, higher frequency allows for higher possible bandwidth or bit rates, and lowers the time it takes to download large files. In general, however, higher frequencies do not pass through walls, making lower frequencies an advantage indoors. Most common equipment reports the highest frequency available, but usually also works at lower ones. Bandwidth is often equated with "speed", while latency ("lag") is the perceived problem (and is a measure distinct from bandwidth); higher bandwidth has an influence on latency.

SI multiples[edit]

SI multiples for hertz (Hz)
Submultiples Multiples
Value SI symbol Name Value SI symbol Name
10−1 Hz dHz decihertz 101 Hz daHz decahertz
10−2 Hz cHz centihertz 102 Hz hHz hectohertz
10−3 Hz mHz millihertz 103 Hz kHz kilohertz
10−6 Hz µHz microhertz 106 Hz MHz megahertz
10−9 Hz nHz nanohertz 109 Hz GHz gigahertz
10−12 Hz pHz picohertz 1012 Hz THz terahertz
10−15 Hz fHz femtohertz 1015 Hz PHz petahertz
10−18 Hz aHz attohertz 1018 Hz EHz exahertz
10−21 Hz zHz zeptohertz 1021 Hz ZHz zettahertz
10−24 Hz yHz yoctohertz 1024 Hz YHz yottahertz
Common prefixed units are in bold face.

Higher frequencies than the International System of Units provides prefixes for are believed to occur naturally in the frequencies of the quantum-mechanical vibrations of high-energy, or, equivalently, massive particles, although these are not directly observable and must be inferred from their interactions with other phenomena. By convention, these are typically not expressed in hertz, but in terms of the equivalent quantum energy, which is proportional to the frequency by the factor of Planck's constant.

See also[edit]

Notes and references[edit]

  1. ^ "hertz". (1992). American Heritage Dictionary of the English Language (3rd ed.), Boston: Houghton Mifflin.
  2. ^ "SI brochure: Table 3. Coherent derived units in the SI with special names and symbols". 
  3. ^ "[Resolutions of the] CIPM, 1964 – Atomic and molecular frequency standards" (PDF). SI brochure, Appendix 1. 
  4. ^ NIST Guide to SI Units – 9 Rules and Style Conventions for Spelling Unit Names, National Institute of Standards and Technology
  5. ^ "(d) The hertz is used only for periodic phenomena, and the becquerel (Bq) is used only for stochastic processes in activity referred to a radionuclide." "BIPM – Table 3". BIPM. Retrieved 2012-10-24. 
  6. ^ "SI brochure, Section 2.2.2, paragraph 6". Archived from the original on 1 October 2009. 
  7. ^ "IEC History". Iec.ch. 1904-09-15. Retrieved 2012-04-28. 
  8. ^ Cartwright, Rufus (March 1967). Beason, Robert G., ed. "Will Success Spoil Heinrich Hertz?" (PDF). Electronics Illustrated. Fawcett Publications, Inc. pp. 98–99. Retrieved 2016-03-29. 
  9. ^ Ernst Terhardt (20 February 2000). "Dominant spectral region". Mmk.e-technik.tu-muenchen.de. Archived from the original on 26 April 2012. Retrieved 28 April 2012. 
  10. ^ "Black Hole Sound Waves - Science Mission Directorate". science.nasa.go. 
  11. ^ Atomic vibrations are typically on the order of tens of terahertz
  12. ^ Asaravala, Amit (2004-03-30). "Good Riddance, Gigahertz". Wired.com. Retrieved 2012-04-28. 

External links[edit]

Disclaimer

None of the audio/visual content is hosted on this site. All media is embedded from other sites such as GoogleVideo, Wikipedia, YouTube etc. Therefore, this site has no control over the copyright issues of the streaming media.

All issues concerning copyright violations should be aimed at the sites hosting the material. This site does not host any of the streaming media and the owner has not uploaded any of the material to the video hosting servers. Anyone can find the same content on Google Video or YouTube by themselves.

The owner of this site cannot know which documentaries are in public domain, which has been uploaded to e.g. YouTube by the owner and which has been uploaded without permission. The copyright owner must contact the source if he wants his material off the Internet completely.

Powered by YouTube
Wikipedia content is licensed under the GFDL and (CC) license