Cov xwm txheej rau kev ua haujlwm sib npaug ntawm ob lossis ntau dua transformers yog:
(1) Qhov ntsuas hluav taws xob ntawm qhov siab thiab qis voltage sab yog sib npaug, thiab qhov sib txawv ntawm qhov kev ua haujlwm yuav tsum sib npaug;
(2) Cov pab pawg sib txuas yuav tsum yog tib yam; (3) Qhov luv-circuit voltage ib chav tsev nqi (feem pua tus nqi) sib npaug.
