Chitetezo cha overvoltage ndi zigawo za munthu payekha zokhala ndi varistors pakupanga kwa terminal
Ma varistors a metal-oxide angagwiritsidwe ntchito popanga ma terminal. Amavomerezedwa kuti akhale ndi voltage yogwira ntchito ya sine-wave-form power-frequency, yomwe imasindikizidwa pa gawolo. Voltage iliyonse yoposa maxi- yololedwa
Ma mum amatulutsidwa bwino mkati mwa 25 ns. Ma Varistors amagwiritsidwa ntchito pa mphamvu yapakati mpaka yapamwamba.