Namhlanje sichaza elinye icandelo elitsha longezwe kuluhlu lwethu, iSchmitt Trigger, into engaziwayo ngabaninzi abaza kuyeka ukuba yimfihlelo. Kwaye siza kuchaza yonke into ofuna ukuyazi ngayo, enje ngokuba yintoni, yeyantoni, sisebenza njani esi sixhobo sombane, kwaye emva koko unokusidibanisa neeprojekthi zakho. Arduino, Njl
Ke, makhe sibone ukuba le nto ingasenzela ntoni...
Iikhonsepthi eziyimfuneko zangaphambili
Ngaphambi kokuba uqale ngeSchmitt Trigger, kuyimfuneko Chaza iikhonsepthi ezimbalwa oko kuya kunceda ukuqonda ngcono ukuba yintoni kwaye isebenza njani. Ndibhekisa ku:
- Thelekisa: Kwi-electronics, umthelekisi sisixhobo esithelekisa ii-voltages ezimbini okanye ii-currents kunye neziphumo zesignali yedijithali ebonisa ukuba yeyiphi enkulu. Ineetheminali ezimbini ze-analog, kunye nemveliso yedijithali enye yokubini. Oku kubalulekile ukuqaphela, njengoko i-Schmitt trigger luhlobo lomthelekisi. Ukongeza, lo mthelekisi ubandakanya iamplifier yokuzuza okuphezulu okukhethekileyo.
- I-Hysteresis: I-Hysteresis yipropati apho imeko yenkqubo ixhomekeke kwimbali yayo. Umzekelo, umazibuthe unokuba nezihlandlo ezahlukeneyo zemagnethi kwintsimi yamagnetic kuxhomekeke kwindlela etshintshe ngayo intsimi kwixesha elidlulileyo, yenze i-hysteresis curves. Le propathi ijongwa kwizixhobo ze-ferromagnetic kunye ne-ferroelectric kunye neziganeko zendalo ezinje ngokuguqulwa kweerubha kunye ne-alloys yememori yokumila. I-Hysteresis ihambelana neenguqu ezingenakuguqulwa, ezifana nokuguqulwa kwesigaba, kwaye ixhaphake kwiinkqubo zendalo. Kutheni ufanele ukwazi oku? Ewe, kuba iSchmitt Trigger yisekethe yokuthelekisa kunye ne-hysteresis.
Yintoni iSchmitt Trigger?
Un Schmitt Trigger, ekwaziwa ngokuba yi-Schmitt trigger kwiSpanish, yi-electronic comparator circuit eguqula i-analog input signal ibe yi-digital output signal. Ikwenza oku ngokufaka ingxelo eyakhayo ukuvelisa indawo yokutshintsha i-hysteretic, oku kuthetha ukuba umda wokutshintsha phakathi kwe-logic "phezulu" kunye ne "low" yamazwe yahlukile ngokunyuka nokuwa komqondiso wegalelo. Oku kuziphatha kwe-hysteretic kuthintela ukuguquguquka okungafunekiyo kwaye kunika umda wokunyamezela kwimiqondiso enengxolo okanye encinci ye-jitter.
Uyilo lwadalwa okokuqala Otto H. Schmitt ngowe-1934, kungoko igama layo. Ukusukela ngoko, eli candelo le-elektroniki lisetyenziswa ngokubanzi kubuninzi bezicelo njengoko siza kubona kamva. Ukongeza, kuya kufuneka wazi ukuba ihlala igqunywe kwisekethe edibeneyo okanye itshiphu, ihlala iDIP, kwaye ihlala ibandakanya iamplifier esebenzayo (op-amp) Ngempendulo eyakhayo nge resistors, enye non-inverting (+) igalelo kunye enye inverting (-) igalelo op-amp zidityaniswe nge chain resistor, kunye resistor eyongezelelweyo kwakhona zibandakanyiwe impendulo elungileyo ukusuka kwimveliso ukuya inverting igalelo. .
Ngokuphathelele ukuziphatha kakubi, kufuneka kuthiwe xa isignali yegalelo idlula umda othile ophezulu, isiphumo seSchmitt Trigger sitshintshela "phezulu", kwaye ukuba isignali yegalelo iyancipha ngaphantsi komgangatho ophantsi ohlukeneyo, isiphumo sitshintsha sibe "phantsi". Umahluko phakathi kwemigangatho emibini ibizwa ngokuba yifestile ye-hysteresis kwaye ibalulekile ekuziphatheni kwe-hysteretic. Oku kuneenzuzo njengoko kuthintela iimpendulo ezikhawulezayo ezingafunekiyo ngenxa yokuguquguquka okuncinci okanye ingxolo kwisignali yegalelo. Ngoko ke, inika ukukhuseleka kwingxolo.
I-Schmitt trigger isetyenziselwa ukuphucula ukugonywa kwengxolo kwisekethe enomda wokungena omnye. Kule meko, isignali enengxolo kufuphi nomgubasi inokubangela utshintsho olukhawulezayo kwimveliso ngenxa yengxolo. I-Schmitt trigger, ngokuba nemigangatho emibini, igwema utshintsho olungafunekiyo, ekubeni isignali enomsindo kufuphi nomqobo ivelisa kuphela utshintsho kwimveliso; Ukwenza olunye utshintsho, umqondiso kufuneka uhambe ngaphaya komnye umqobo.
Un umzekelo osebenzayo Ibandakanya ifotodiode ye-infrared eyandisiweyo eyenza umqondiso otshintshayo phakathi kwamaxabiso agqithisileyo. Lo mqondiso ugudiswa ngesihluzo esisezantsi, kwaye imveliso ehluziweyo ixhunyiwe kwi-trigger ye-Schmitt. Esi sixhobo siqinisekisa ukuba imveliso ihamba kuphela ukusuka ezantsi ukuya phezulu emva kokuba isignali ye-infrared ivuyisa ifotodiode ixesha elide kunexesha elaziwayo. Nje ukuba i-Schmitt trigger iphezulu, ibuyela ezantsi kuphela emva kokuba isignali ye-infrared iyeke ukuvuyisa ifotodiode ixesha elide kunexesha elifanayo elaziwayo. Oku kuthintela utshintsho olungeyonyani olubangelwa yingxolo yendalo esingqongileyo. I-Schmitt triggers ixhaphake ekutshintsheni iisekethe, ezifana nokutshintsha kweeswitshi.
Indlela iSchmitt Trigger isebenza ngayo
Iisekethe ezine-hysteresis zisekelwe kwi impendulo eyakhayo, okwenza kube lula ukuguqula nayiphi na isekethe esebenzayo kwi-Schmitt trigger ngokufaka ingxelo efanelekileyo kunye nenzuzo ye-loop enkulu kuneyodwa. Ingxelo encomekayo ibandakanya ukongeza enye i-voltage ephumayo kwi-voltage yegalelo. Ezi zijikelezo, ezibandakanya i-attenuator, i-adder, kunye ne-amplifier esebenza njenge-comarator, inokuphunyezwa ngokusebenzisa iindlela ezintathu ezikhethekileyo.
Iindlela ezimbini zokuqala zi iinguqulelo ezimbini (uthotho kunye nokuhambelana) kwenkqubo yempendulo elungileyo. Kolu lungelelwaniso, amandla ombane ophumayo aguqula umahluko osebenzayo wombane wokufaka umthelekisi, mhlawumbi 'ngokunciphisa umda' okanye 'ngokunyusa amandla ombane wokungenisa isekethe'. Olu lungelelwaniso lubandakanya umda kunye neempawu zememori kwinto enye. Endaweni yoko, ubuchule besithathu bohlula umda kunye neepropathi zememori, zibonelela ngokuguquguquka okukhulu ekuphunyezweni kwesekethe.
Izinto eziluncedo kunye nezicelo
I-Schmitt Triggers inokusetyenziselwa usetyenziso oluninzi ngokuxhomekeke kuqwalaselo, umzekelo:
- I-Analog ukuya kwinguquko yedijithali- Eli candelo liyi-bit-bit analog-to-digital converter. Xa umqondiso ufikelela kwinqanaba elinikeziweyo, litshintsha ukusuka kwindawo ephantsi ukuya kwindawo ephezulu.
- Ukufunyanwa kwenqanaba-Iyakwazi ukubonelela ngokuchongwa kwinqanaba. Xa usenza esi sicelo, kuyimfuneko ukuqwalasela i-voltage ye-hysteresis ukwenzela ukuba isiphaluka sitshintshe ngombane ofunekayo.
- Ulwamkelo lomgca- Xa kuziswa umgca wedatha onokuthi uqokelele ingxolo kwisango lengqiqo, kuyimfuneko ukuqinisekisa ukuba inqanaba lesiphumo sengqiqo liyatshintsha kuphela xa ulwazi lutshintsha kwaye kungekhona ngenxa yengxolo ephosakeleyo eqokelelwayo. Ukusetyenziswa kwe-Schmitt trigger ivumela ukuba ingxolo ye-peak-to-peak ifikelele kwinqanaba le-hysteresis ngaphambi kokuba i-spurious trigger ingenzeka.
Njengeemeko ezithe ngqo ngakumbi, unokuzibona kwiisekethe apho ufuna ukuphelisa ukubhobhoza kumaqhosha oomatshini, kwiijenereyitha zamaza asisikwere, kwii-detectors zamanqanaba, kwiisekethe zokukhusela ingxolo yomgca wedatha, iijenereyitha zepulse, kunye nabaguquleli abadumileyo.
Sebenzisa njenge-oscillator
I-Schmitt trigger yi-bistable multivibrator leyo ingasetyenziselwa ukuphumeza olunye uhlobo lwe-multivibrator, i-oscillator yokuphumla. Oku kuphunyezwa ngokudibanisa i-RC enye yesekethe yokudibanisa phakathi kwemveliso kunye negalelo le-Schmitt trigger eguqulweyo. Imveliso iya kuba yi-square wave eqhubekayo apho i-frequency yayo ixhomekeke kumaxabiso e-R kunye ne-C, kunye neendawo zomda we-Schmitt trigger. Ekubeni i-IC enye inokubonelela ngee-triggers ezininzi ze-Schmitt (umzekelo, uhlobo lwe-4000 40106 uchungechunge lwesixhobo se-CMOS luqulethe i-6 kubo), icandelo elongezelelweyo le-IC linokusetyenziswa ngokukhawuleza njenge-oscillator elula kwaye ethembekileyo enamacandelo amabini angaphandle.
Kule meko, i-trigger esekelwe kwi-Schmitt isetyenziswe kuqwalaselo lwayo oluguquliweyo. Ukongeza, ingxelo ecothayo engalunganga yongezwa kunye nenethiwekhi edibeneyo yeRC. Isiphumo kukuba imveliso ngokuzenzekelayo ukusuka VSS ukuya VDD njengoko i-capacitor ihlawulisa ukusuka kwelinye inqanaba le-Schmitt trigger ukuya kwelinye.
Ukuphuma
Kufuneka ukhumbule ukuba ngokutsho imodeli yepinout Inokutshintsha, ke ndincoma ukuba uhlale ubona idatadata yomenzi ehambelana nemodeli oyithengileyo. Nangona kunjalo, njengomzekelo, apha sine-chip ye-74LS14 TTL ene-6 i-triggers ngaphakathi. Ke ngoko, sinephini enye ye-DIP eya kuba yeyamandla eVcc, kunye nenye yeyomhlaba okanye ye-GND. Yile ndlela zonke ii-triggers zinikwe amandla ngayo, kwaye ke kuya kuba ngumcimbi wokusebenzisa igalelo kunye nesiphumo esikufanelayo.
Ukuthenga phi
Okokugqibela, ukuba uyafuna Thenga enye yezi Schmitt Trigger, Ungazifumana kwiivenkile ezikhethekileyo okanye kumaqonga okuthengisa kwi-intanethi anje ngeAmazon:
