I^2R Otpornost - Snaga otpornika u zavisnosti od specifične toplote materijala - II deo.

Ovo je nastavak na I^2R Otpornost blog posta, u kojem prikazujem ono što sam naveo u prvom blog postu o otpornosti a to je da snaga istog zavisi od materijala od kojeg se otpornik proizvodi. Ranije sam nabavio knjigu preko InfoElektronika magazina o Merenju otpornosti i generalno o otpornosti, iz koje sam preuzeo odličnu jednačinu snage koja se menja u diferencijalu vremena. Ovde navodim istu uz objašnjenje, ali isto tako navodim i primer vezan za štampane pločice i temperaturni odnos bakra i tinol žice, iz kog razloga pogledajte u video klipu.

Video klip - prikaz jednačine snage otpornika koja zavisi od više faktora a jedan od njih je i specifična toplota materiala od kojeg je otpornik napravljen. Datu jednačinu sam prikazao dole u nastavku blog posta uz naznaku da je preuzeta iz knjige Električna otpornost - pojava i merenje koju možete nabaviti preko zvaničnog web sajte InfoElektronika, naveden je naravno samo deo.

Jednačina snage koja se menja u diferencijalu vremena. Jasno se vidi da je snaga otpornika kontinualna funkcija vremena i prikazuje promenu iste čim se na otpornika dovede snaga tj. konstantni napon i konstantna struja. Jedan od faktora je i specifična toplota materijala od kojeg je otpornik proizveden. Ovo je preuzeto iz knjige Električna otpornost - pojava i merenje, koju možete nabaviti preko InfoElektronika magazina.
Primer ugljenoslojnog otpornika, primer preuzet sa web site-a: M&G Electronic

Primer metal film otpornika, primer preuzet sa web site-a: M&G Electronic

Primer keramičkog otpornika, primer preuzet sa web site-a: M&G Electronic

Primer otpornika sa hladnjakom, primer preuzet sa web site-a: M&G Electronic. Ovaj
primer otpornika je dobar jer poseduje hladnjaka, sa isimt zapravo radi se odstranjivanje viška toplote sa istog kako bi se snaga otpornika održavala u željenoj dizajniranoj vrednosti, jer promena snage nastaje od samog trenutka kada kroz otpornik protiče električna struja. Na ovakav hladnjak se ili eksterno montira pasivno halđenje ili se poveže na PCB a zatim se toplota odvodi kroz bakarne žice na GROUND.

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Autor: Vladimir Savić


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