Uhlelo lokuqapha izivikelo zokuduma kwezinto zikagesi luyisistimu ehlakaniphile esetshenziselwa ukuqapha ngesikhathi sangempela ukusebenza kukagesi kanye nesimo sokuguga kwezivikelo ze-metal oxide (MOA), okuhloswe kakhulu kwezengozi ezimbili ezinkulu zokuvikelwa kwe-overvoltage yokuduma kwezulu okuhlulekile kanye nokuvuza okuqhubekayo okungajwayelekile, ukuze kuxwayiswe kusenesikhathi ukuthi isivikelo sombani siqukethe umswakama, ukuguga noma ukungcola, ukuqinisekisa ukusebenza okuphephile kwenethiwekhi kagesi.