Hertz

The hertz (symbol: Hz) is the unit of <a href="/facts/Frequency/QUSbPaW8">frequency</a> in the <a href="/facts/International_System_of_Units/S7YLglNz">International System of Units</a> (SI), often described as being equivalent to one event (or <a href="/facts/Cycle_per_second/WxtGGRFx">cycle</a>) per <a href="/facts/Second/jtFxnJXx">second</a>. The hertz is an <a href="/facts/SI_derived_unit/RLu52lWy">SI derived unit</a> whose formal expression in terms of <a href="/facts/SI_base_unit/M7PsTWg4">SI base units</a> is 1/s or s−1, meaning that one hertz is one per second or the <a href="/facts/Inverse_second/W0Iqf8EL">reciprocal of one second</a>. It is used only in the case of periodic events. It is named after <a href="/facts/Heinrich_Hertz/sbL2MSpM">Heinrich Rudolf Hertz</a> (1857–1894), the first person to provide conclusive proof of the existence of <a href="/facts/Electromagnetic_wave/Ynx7ujCW">electromagnetic waves</a>. For high frequencies, the unit is commonly expressed in <a href="/facts/Metric_prefix/Y2MzkaeL">multiples</a>: kilohertz (kHz), megahertz (MHz), gigahertz (GHz), terahertz (THz).
Some of the unit's most common uses are in the description of <a href="/facts/Periodic_waveform/yAskMREw">periodic waveforms</a> and <a href="/facts/Musical_tone/dL8Bck9W">musical tones</a>, particularly those used in <a href="/facts/Radio/XFr909M2">radio</a>- and audio-related applications. It is also used to describe the <a href="/facts/Clock_speed/w055Woaj">clock speeds</a> at which computers and other electronics are driven. The units are sometimes also used as a representation of the <a href="/facts/Photon_energy/Gy4zEAaE">energy of a photon</a>, via the <a href="/facts/Planck_relation/KR8u3qPV">Planck relation</a> E = hν, where E is the photon's energy, ν is its frequency, and h is the <a href="/facts/Planck_constant/qGHAe3qq">Planck constant</a>.

Hertz open-in-new

Hertz