Om
Om (symvol: Ω) — Xalqaro birliklar tizimi SIdagi elektr karshilik birligi. Om (Ω) bilan belgilanadi. Oʻtkazgichdan oʻtayotgan oʻzgarmas tok kuchi 1 amper va uning uchlaridagi kuchlanish 1 Volt boʻlganda uning qarshiligi 1 Om ga teng boʻla-di, yaʼni 1 Om=V/A. G. S. Om sharafiga qoʻyilgan. Ω = V A = 1 S = W A 2 = V 2 W = s F = H s = J ⋅ s C 2 = kg ⋅ m 2 s ⋅ C 2 = J s ⋅ A 2 = kg ⋅ m 2 s 3 ⋅ A 2 {\displaystyle \Omega ={\dfrac {\text{V}}{\text{A}}}={\dfrac {1}{\text{S}}}={\dfrac {\text{W}}{{\text{A}}^{2}}}={\dfrac {{\text{V}}^{2}}{\text{W}}}={\dfrac {\text{s}}{\text{F}}}={\dfrac {\text{H}}{\text{s}}}={\dfrac {{\text{J}}{\cdot }{\text{s}}}{{\text{C}}^{2}}}={\dfrac {{\text{kg}}{\cdot }{\text{m}}^{2}}{{\text{s}}{\cdot }{\text{C}}^{2}}}={\dfrac {\text{J}}{{\text{s}}{\cdot }{\text{A}}^{2}}}={\dfrac {{\text{kg}}{\cdot }{\text{m}}^{2}}{{\text{s}}^{3}{\cdot }{\text{A}}^{2}}}}