Nhasi tinotsanangura chimwe chikamu chitsva chakawedzerwa kune yedu chinyorwa, iyo Schmitt Trigger, chisingazivikanwi nevazhinji avo zvino vacharega kuva chakavanzika. Uye isu tichatsanangura zvese zvaunoda kuziva nezvazvo, senge kuti chii, kuti ndechei, mashandiro echigadzirwa chemagetsi ichi, uye kunyangwe ipapo unogona kuzvibatanidza nemapurojekiti ako ne. Arduino, Etc.
Saka, ngationei kuti chinhu ichi chingatiitirei...
Mazano ekutanga anodikanwa
Usati watanga neSchmitt Trigger, zvinodikanwa tsanangura pfungwa mbiri izvo zvichauya zvakanaka kuti unzwisise zviri nani kuti chii uye kuti chinoshanda sei. Ndiri kureva:
- Muenzanisi: Mumagetsi, muenzanisi mudziyo unofananidza ma voltages maviri kana macurrents uye unoburitsa chiratidzo chedhijitari chinoratidza kuti chikuru ndechipi. Iyo ine maviri analog yekupinza zviteshi, uye imwe bhinary digital inobuda. Izvi zvakakosha kucherechedza, sezvo Schmitt trigger iri rudzi rwemuenzanisi. Pamusoro pezvo, uyu muenzanisi ane nyanzvi yepamusoro kuwana musiyano amplifier.
- Hysteresis: Hysteresis inzvimbo umo mamiriro ehurongwa zvinoenderana nenhoroondo yayo. Semuyenzaniso, magineti anogona kuva nenguva dzakasiyana dzemagineti mundima yemagineti zvichienderana nekuti munda wakachinja sei kare, uchigadzira hysteresis curves. Ichi chivakwa chinocherechedzwa mune ferromagnetic uye ferroelectric zvinhu uye zvakasikwa zviitiko senge deformation yerubha uye chimiro chendangariro alloys. Hysteresis inosanganiswa nekuchinja kusingadzoreki, sekushanduka kwechikamu, uye inowanzoitika mumasikirwo emasikirwo. Sei uchifanira kuziva izvi? Zvakanaka, nekuti Schmitt Trigger idunhu rekuenzanisa ne hysteresis.
Chii chinonzi Schmitt Trigger?
Un Schmitt Trigger, inozivikanwawo seSchmitt trigger muchiSpanish, idunhu remagetsi rekuenzanisa rinoshandura chiratidzo chekuisa analogi kuita chiratidzo chedhijitari. Inoita izvi nekushandisa mhinduro yakanaka kugadzira hysteretic switching point, zvichireva kuti chikumbaridzo chekuchinja pakati peiyo logic "yepamusoro" uye "yakaderera" nyika dzakasiyana pakusimuka nekudonha kwechiratidzo chekuisa. Iyi hysteretic maitiro inodzivirira kuchinjika kusingadiwi uye inopa kushivirira muganho kune ruzha kana diki-jitter masaini masaini.
Iyo yakagadzirwa yakagadzirwa kwekutanga Otto H. Schmitt muna 1934, nokudaro zita racho. Kubva ipapo, ichi chikamu chemagetsi chinoshandiswa zvakanyanya muhuwandu hwekushandisa sezvatichaona gare gare. Uye zvakare, iwe unofanirwa kuziva kuti inowanzovharirwa mune yakabatanidzwa dunhu kana chip, kazhinji DIP, uye kuti inowanzo sanganisira amplifier inoshanda (op-amp) Iine mhinduro yakanaka kuburikidza nevanopikisa, imwe isiri-inverting (+) yekuisa uye imwe inverting (-) yekuisa ye-op-amp yakabatana kuburikidza neketani yekupikisa, uye imwe inopikisa inosanganisirwawo kune mhinduro yakanaka kubva kune inobuda kuenda kune inverting yekupinda. .
Kana ari hystertic maitiro, inofanira kutaurwa kuti kana chiratidzo chekupinza chinopfuura chimwe chikumbaridzo chepamusoro, kubuda kweSchmitt Trigger kunoshanduka kune "yakakwirira", uye kana chiratidzo chekuisa chinodonha pasi pechikumbaridzo chakasiyana chezasi, kubuda kunoshanduka kune "pasi". Musiyano uri pakati pezvikumbaridzo zviviri unonzi hysteresis hwindo uye wakakosha pakuita hysteretic. Izvi zvine zvakanakira sezvo zvichidzivirira zvisingadiwe nekukurumidza mhinduro nekuda kwekuchinja kudiki kana ruzha muchiratidzo chekuisa. Naizvozvo, inopa kusadzivirirwa kune ruzha.
Iyo Schmitt trigger inoshandiswa kunatsiridza ruzha kudzivirirwa mudunhu rine chikumbaridzo chimwe chete chekupinda. Muchiitiko ichi, chiratidzo chine ruzha padyo nechikumbaridzo chinogona kukonzera shanduko nekukurumidza mukubuda nekuda kweruzha. Iyo Schmitt inokonzeresa, nekuve nezvikumbaridzo zviviri, inodzivirira shanduko isingadiwe, sezvo chiratidzo chine ruzha chiri pedyo nechikumbaridzo chinongoburitsa shanduko mukubuda; Kuti uite imwe shanduko, chiratidzo chinofanira kufamba kupfuura chimwe chikumbaridzo.
Un muenzaniso unoshanda Inosanganisira amplified infrared photodiode inogadzira chiratidzo chinoshanduka pakati pezvakanyanyisa kukosha. Ichi chiratidzo chinokwenenzverwa nesefa-pasi-pasi, uye iyo yakasefa inobuda yakabatana kune Schmitt trigger. Chishandiso ichi chinova nechokwadi chekuti inobuda inongoenda kubva pasi kuenda kumusoro mushure meiyo infrared siginecha inonakidza iyo photodiode kwenguva yakareba kupfuura inozivikanwa nguva. Kamwe iyo Schmitt trigger yakakwira, inongodzokera kune yakaderera mushure meiyo infrared siginecha yamira kunakidza iyo photodiode kwenguva yakareba kupfuura yakafanana inozivikanwa nguva. Izvi zvinodzivirira shanduko dzenhema dzinokonzerwa neruzha kwezvakatipoteredza. Schmitt zvinokonzeresa zvakajairika mukuchinja maseketi, senge debouncing switch.
Iyo Schmitt Trigger inoshanda sei
Masenhu ane hysteresis anobva pane mhinduro yakanaka, zvichiita kuti zvikwanise kushandura chero dunhu rinoshanda kuita Schmitt trigger nekushandisa mhinduro yakanaka ine loop kuwana yakakura kupfuura imwe. Positive mhinduro inosanganisira kuwedzera imwe yevoltage inobuda kune voltage yekupinza. Aya maseketi, anosanganisira attenuator, adder, uye amplifier inoshanda semuenzanisi, anogona kuitwa uchishandisa matatu chaiwo matekiniki.
Maitiro maviri ekutanga ndiwo versions mbiri (yakatevedzana uye yakafanana) yeiyo general positive mhinduro system. Mune izvi zvigadziriso, iyo inobuda voltage inogadzirisa musiyano unoshanda weiyo comparator yekuisa voltage, kungave ne 'kudzikisa chikumbaridzo' kana ne 'kuwedzera dunhu rekuisa voltage'. Izvi zvigadziriso zvinosanganisira chikumbaridzo uye ndangariro zvimiro muchinhu chimwe chete. Panzvimbo iyoyo, iyo yechitatu tekinoroji inoparadzanisa chikumbaridzo uye ndangariro zvivakwa, ichipa kushanduka kukuru mukuitwa kwedunhu.
Zvishandiso uye maapplication
Schmitt Triggers inogona kushandiswa kune akati wandei anoshanda zvinoenderana nekumisikidzwa, semuenzaniso:
- Analogi kuenda kudhijitari shanduko- Ichi chikamu chinonyatso shandura analog-to-digital converter. Kana chiratidzo chasvika padanho rakapihwa, chinoshanduka kubva pakuderera kusvika pakakwirira.
- Kuonekwa kwemazinga- inokwanisa kupa nhanho yekuona. Paunenge uchiita ichi chishandiso, zvinodikanwa kufunga nezve hysteresis voltage kuitira kuti dunhu richinje nemhepo inodiwa.
- Line reception- Kana uchiunza mutsara wedata unogona kunge wasimudza ruzha kugedhi rine logic, zvinodikanwa kuve nechokwadi chekuti logic yekubuda level inongochinja kana ruzivo rwachinja uye kwete nekuda kweruzha rwekunyepedzera rwuri kutorwa. Kushandiswa kweSchmitt trigger kunobvumira ruzha rwepamusoro-kusvika-peak kusvika padanho rehysteresis kusati kwaitika kukonzeresa kwenhema.
Sezvimwe zviitiko zvakanyanya, unogona kuzviona mumaseketi kwaunoda kubvisa mabhatani mumabhatani emuchina, mune square wave jenareta, mumatanho edhijitari, mune data mutsara wekudzivirira ruzha maseketi, pulse jenareta, uye ane mukurumbira anoshandura.
Shandisa se oscillator
A Schmitt trigger is bistable multivibrator iyo inogona kushandiswa kuita imwe mhando ye multivibrator, iyo yekuzorodza oscillator. Izvi zvinowanikwa nekubatanidza imwe RC yekubatanidza dunhu pakati pekubuda nekupinza kweiyo inverted Schmitt trigger. Iyo inobuda ichave inoenderera sikweya wave iyo frequency inotsamira pane kukosha kweR uye C, pamwe nemapoinzi echikumbaridzo cheSchmitt trigger. Sezvo IC imwe chete inogona kupa akati wandei Schmitt trigger (semuenzaniso, mhando 4000 40106 yakatevedzana CMOS mudziyo ine 6 yacho), chimwe chikamu cheIC chinogona kukurumidza kushandiswa seyakapusa uye yakavimbika oscillator ine zvikamu zviviri zvekunze.
Muchiitiko ichi, muenzanisi-based Schmitt trigger inoshandiswa mune yayo inverted configuration. Pamusoro pezvo, mhinduro inononoka yakaipa inowedzerwa neRC inobatanidza network. Mhedzisiro yacho ndeyekuti zvinobuda zvinobva paVSS kuenda kuVDD sezvo capacitor ichichaja kubva kune imwe chikumbaridzo cheSchmitt trigger kune imwe.
Buda-kunze
Unofanira kuyeuka kuti maererano pinout modhi Inogona kuchinja, saka ini ndinokurudzira kuti ugare uchiona dhetabheti yemugadziri inoenderana nemuenzaniso wawakatenga. Nekudaro, semuenzaniso, pano isu tine 74LS14 TTL chip ine 6 inokonzeresa mukati. Naizvozvo, tine pini imwe yeDIP ichave yeVcc simba, uye imwe yepasi kana GND. Aya ndiwo mabatirwo anoitwa zvese zvinokonzeresa, uye zvino ichave nyaya yekushandisa iyo yekupinza uye inobuda inokodzera iwe.
Kwatenga
Chekupedzisira, kana uchida tenga imwe yeiyi Schmitt Trigger, Unogona kuzviwana muzvitoro zvine hunyanzvi kana pamapuratifomu ekutengesa epamhepo akadai seAmazon:
