Inkqubo efanayo ijongene nokusombulula ingxaki yokuba ibhetri ene-voltage ephezulu itshaja kwibhetri ene-voltage ephantsi ngenxa yomahluko we-voltage phakathi kweebhetri.
Ngenxa yokuba ukumelana kwangaphakathi kweseli yebhetri kuphantsi kakhulu, ngoko ke umsinga wokutshaja uphezulu kakhulu, nto leyo enokuba yingozi. Sithi i-1A, 5A, 15A ibhekisa kumsinga olinganiselweyo wokutshaja ibhetri.