Yayin da ma'aunin ma'aunin shine girman da aka kafa don tantance girman abubuwan da ba a iya lissafa su daga 'ƙidayar raka'a ɗaya', Rukunin da aka samo su ne waɗanda aka samo daga raka'a ma'aunin, kuma ana amfani da su don ƙarin takamaiman adadi.
Nau'in ma'aunin tsayin (mita), ɗaya na taro (kilogram), ɗaya na lokaci (na biyu), ɗaya na wutar lantarki (ampere), ɗaya na zafin jiki (kelvin), ɗayan adadin abu ( mole), kuma ɗayan ƙarfin haske (candela). Daga waɗannan bakwai akwai yuwuwar yin haɗin gwiwa wanda ya ƙare har ya kai ga kowane rukunin da aka samo, ya zama dole don auna wani nau'in abubuwan mamaki. Kodayake ba su ne raka'a ta asali ba, har yanzu suna da matukar mahimmanci ga ɗan adam: Ba tare da raka'a da aka samo ba, ma'aunin ƙarfi, kuzari, matsin lamba, iko, gudu ko hanzari ba zai yiwu ba.
Kamar yadda a ma'aunin ma'auni na al'ada, raka'a da aka samo kuma suna ba da ikon yin juyawa tsakanin iri daban -daban. Misali, ana yawan amfani da ma'aunin ma'aunin 'Newton' don auna girman ƙarfin, amma kuma akwai ma'aunin ma'aunin 'Dina', ƙarƙashin alaƙar da 1 newton yayi daidai da dauloli 100,000. Haka abin yake faruwa tare da auna makamashi, aiki da zafi: Ana amfani da Joules a fagen kimiyya, amma ana amfani da kalori a rayuwar yau da kullun. Alaƙar tana da layi, gwargwadon adadin kuzari shine 4.181 joules.
Jerin da ke biye yana ɗauke da misalai goma sha biyar na sassan da aka samo, suna nuna abin da za su wakilce, da haɗuwar ma'aunin ma'auni na ƙaddara su.
- Mita ta biyu (ma'aunin sauri ko saurin): Mita / Na biyu
- Mita mai siffar sukari (auna ƙarar): mita3
- Pascal (ma'aunin matsin lamba): Kilogram / (Meter * Na biyu2)
- Henry (ma'aunin inductance): (Kilogram * Ampere2 * Jirgin karkashin kasa2) / Na Biyu2
- Mita na daƙiƙa biyu (ma'aunin hanzari): Mita / Na Biyu2
- Hertz (ma'aunin mita): 1 / Na biyu
- Pascal na biyu (ma'aunin danko mai ƙarfi): Kilogram / (Meter * na biyu)
- Kilogram a kowace mita mai siffar sukari (ma'aunin yawa): Kilogram / Meter3
- Mita murabba'i (ma'aunin yanki): Mita2
- Volt (ma'aunin ƙarfin wutar lantarki): (mita2 * Kilogram) / (Ampere * Na biyu3)
- Newton mita (ma'aunin lokacin ƙarfi): (Meter2 * Kilogram) / Na biyu2
- Joule da mita mai siffar sukari (ma'aunin ƙarfin kuzari): Kilogram / (Meter * Na biyu2)
- Coulomb (ma'aunin cajin wutar lantarki): Ampere * Na biyu
- Mole da mita mai siffar sukari (ma'aunin taro): Mol / Meter3
- Watt (ma'aunin wuta): (mita2 * Kilogram) / Na biyu3
