Bó͘-lú-to͘h

1.5 V ê 2 hō tiān-tî.

Bó͘-lú-to͘h ia̍h volt sī piáu-sī tiān-ap ê SI cho͘-ha̍p tan-ūi, kì chò V. 1 V sī tēng-gī chò hō͘ 1 ampere ê tiān-liû sán-seng 1 oá ê kong-lu̍t ê tiān-ūi-chha (potential difference), khiā kóng:

${\mbox{V}}={\mbox{W}}\cdot {\mbox{A}}^{-1}={\mbox{J}}\cdot {\mbox{C}}^{-1}={\mbox{m}}^{2}\cdot {\mbox{kg}}\cdot {\mbox{s}}^{-3}\cdot {\mbox{A}}^{-1}$.