IPA(key): [ɐm⁽ʲ⁾ˌpʲer ˈt͡ɕasʊ] <span class="searchmatch">ампе́р</span>-<span class="searchmatch">ча́су</span> • (ampér-čásu) m inan dative singular of <span class="searchmatch">ампе́р</span>-ча́с (ampér-čás)...
Bulgarian Wikipedia has an article on: <span class="searchmatch">ампер</span>-час Wikipedia bg а́мперча́с (ámperčás) Analysable as <span class="searchmatch">а́мпер</span> (ámper, “ampere”) + час (čas, “hour”), possibly...