Lub moos tsuas yog hu ua "clock," thiab txhua yam khoom siv sijhawm tuaj yeem hu ua cov twj ntsuas sijhawm. Hauv Suav niaj hnub no, lo lus " moos" feem ntau muaj ob lub ntsiab lus: ib qho yog lub ntsiab lus dav dav rau txhua yam ntawm moos thiab watches, thiab lwm yam tshwj xeeb yog hais txog cov watches loj, tshwj xeeb tshaj yog cov neeg kho tshuab moos nrog lub pendulum mechanism.
Cov moos yog cov kev tsim ua ntej tshaj plaws ntawm tib neeg, tsim los ntsuas lub sijhawm tsis tu ncua. Qee lub sij hawm ntuj tsim (xws li hnub, leap hli, thiab xyoo) tuaj yeem pom, thaum lub sijhawm luv luv yuav tsum tau siv lub moos. Ntau txhiab xyoo dhau los, cov hauv paus ntsiab lus ntawm cov cuab yeej siv sijhawm tau hloov pauv ntau. Sundials siv cov duab ntxoov ntxoo hloov pauv los ntawm cov khoom ntawm lub dav hlau los qhia lub sijhawm, thiab ntau yam cuab yeej rau kev suav cov sij hawm sib txawv tau tshwm sim, suav nrog cov zoo tshaj plaws -paub moos moos.
Cov moos dej siv ua ke nrog sundials yog kab tias cov cuab yeej siv sijhawm ntxov tshaj plaws. Teb chaws Europe tau tsim txoj kev khiav tawm hauv 1300 thiab tom qab ntawd tsim thawj lub moos, uas tuaj yeem siv lub sijhawm ua haujlwm oscillating xws li lub log sib npaug.
Cua-tsav moos tau tshwm sim nyob ib ncig ntawm lub xyoo pua 15th, thiab kev lag luam clockmaking pib los ntawm 15th mus rau 16th centuries. Lub invention ntawm lub pendulum moos nyob rau hauv 1656 ntxiv txhim kho qhov tseeb ntawm lub sij hawm. Qhov kev thov rau lub sijhawm kom meej meej hauv kev taw qhia lub sijhawm ntawd kuj txhawb kev txhim kho hauv kev ntseeg tau thiab raug ntawm cov moos. Cov moos hluav taws xob tau tsim nyob rau xyoo 1840, thiab kev txhim kho ntawm cov khoom siv hluav taws xob hauv xyoo pua 20th ua rau cov moos uas tuaj yeem ua haujlwm tag nrho yam tsis muaj kev siv tshuab.
Lub sij hawm lub sij hawm nyob rau hauv niaj hnub moos yog ib tug resonant oscillator, ib yam khoom uas oscillates ntawm ib tug ruaj, meej zaus. Resonant oscillator tuaj yeem yog lub pendulum, tuning diav rawg, quartz siv lead ua, lossis oscillation ntawm electrons hauv atom emitting microwaves.
Analog moos siv ob txhais tes thiab lub kaum ntse ntse los qhia lub sijhawm, thaum cov moos digital siv cov lej. Muaj ob lub sijhawm tso saib: 12-teev thiab 24-teev. Cov moos digital feem ntau siv cov khoom siv hluav taws xob thiab LCD, LED, thiab lub tshuab nqus tsev fluorescent los qhia lub sijhawm. Lub moos ua haujlwm tseem yog ib qho qauv ntawm cov khoos phis tawj niaj hnub, xov tooj ntawm tes, thiab ntsiav tshuaj.
