1. Muaj peev xwm txaus: siv cov khoom siv raw khoom hauv tsev thiab txawv teb chaws, muaj peev xwm txaus, tsis muaj kev tiv thaiv sab hauv, thiab ruaj khov voltage
2. Kev ua haujlwm ruaj khov: lub neej voj voog ntev, lub zog siab ceev, kev ua haujlwm kub ntau yam, ruaj khov tawm voltage