Txhua lub xov tooj ntawm tes chargers yog tsim los ntawm cov khoom siv hluav taws xob ruaj khov (feem ntau yog tswj hwm lub zog, muab kev ua haujlwm ruaj khov thiab txaus tam sim no) ntxiv rau cov kev tswj xyuas tsim nyog xws li tam sim no, voltage limiting, lub sij hawm txwv, thiab overshoot.
Cov zis tsis muaj cim rau ntawm tus thawj charger (xa mus rau cov kab charger): xws li cov zis 4.4V / 1A, cov zis 5.9V / 400mA, xa mus rau qhov tsis sib xws ntawm cov khoom siv hluav taws xob sab hauv. Piv txwv li, cov zis 4.4V tuaj yeem siv rau 4.5V li, thiab 5.9V tuaj yeem siv rau 6V li.