Namuhla, i-PLC ingathola amasiginali we-encoder kanye nezinzwa ngaphandle kweamplifier, ngakho-ke yini ejabulisayo "ngomthombo" kanye "nokukhipha amanzi"? Okuphumayo kwe-PLC kuphela okuzoba nemiqondo ethi "umthombo" kanye "nokuvuza".

Eqinisweni, ngaphandle kwe-Japan PLC, akudingekile ukuthi amanye ama-PLC asebenzise izifinyezo ezinjengokuthi "umthombo" kanye "nokukhipha amanzi", kodwa i-PNP ne-NPN ingasetshenziswa ngokuqondile.

I-PNP iwumugqa womphakathi one-voltage ephansi, futhi i-NPN iwumugqa womphakathi onamandla amakhulu. Uma nje lokhu kuxhumana kulungile, kubonakala sengathi akunandaba ukuthi imiqondo ethi "umthombo" kanye "nokukhipha amanzi" ihlehlisiwe. Kodwa-ke, omunye umqondo "i-positive logic kanye ne-negative logic" nawo awulungile, okuzokwenza ukuthi isignali iguqulwe.

I-Positive logic kanye ne-negative logic

Kumasekhethi ohlobo lwe-PNP, itheminali evamile yokuphakelwa kwamandla nesignali isezingeni eliphansi elingu-0V. Uma okokufaka kusezingeni eliphansi, awukho umehluko we-voltage netheminali evamile, ngakho-ke akukho okukhiphayo kwesignali yokushintsha ekhulisiwe (ubuningi bedijithali ngu-0). Kuphela uma okokufaka kusezingeni eliphezulu, kunomehluko we-voltage netheminali evamile futhi isignali yokushintsha ekhulisiwe iphuma ezingeni eliphezulu. Le modi yedijithali (ubuningi bedijithali ngu-1) esebenza ngempumelelo uma isignali isezingeni eliphezulu ibizwa ngokuthi i-PNP positive logic.

Kumjikelezo we-NPN, ukuphela okuvamile kokunikezwa kwamandla kanye nesignali kusezingeni eliphezulu (isici salesi sekethi se-amplifier). Uma okokufaka kusezingeni eliphezulu, awukho umehluko we-voltage phakathi kokokufaka nokuphumayo, ngakho-ke akukho okukhiphayo kwesignali yokushintsha (inani ledijithali ngu-0). Kuphela uma okokufaka kusezingeni eliphansi (ukwenza ifaneli), kukhona ukuphuma kwesignali yokushintsha, futhi lesi siginali iyasebenza (ubuningi bedijithali yimodi yedijithali engu-1) ezingeni eliphansi, elibizwa ngokuthi i-NPN negative logic.