Nkọwa Dị Mkpirikpi:

Ihe njide ọkụ bụ ihe nchebe oke voltaji, ọkachasị maka nchekwa nke sistemụ ike eletrik, sistemụ eletriki ụgbọ okporo ígwè, sistemụ nkwukọrịta na ọtụtụ ngwa eletriki (transformer,
switch, capacitor, trapper, transformers, jeneratores, motos, waya ike) site na ikuku over voltaji, overvoltaji na transient over-voltaji mmebi dị otú ahụ, bụ ntọala nke nhazi mkpuchi sistemu ike.
Ihe njide elu metal oxide nke ihe ndị bụ isi (resistors) nwere usoro dị elu dabere na zinc oxide, nwere njirimara na-abụghị ahịrị (VA) dị oke mma, ya bụ na voltaji ọrụ nkịtị, nke na-agafe naanị ogbo microampere, mgbe a na-etinye ya na voltaji, nke na-erute ọtụtụ puku amperes, nke na-eme na voltaji steeti na-ejide àmụ̀mà, ntọhapụ nke ike, si otú a na-egbochi nke ọma.
oke voltaji na mmebi nke nnyefe ike na akụrụngwa mgbanwe.
Ihe njide siri ike nke silicon carbide ọdịnala bụ n'ihi igbu oge mwepụta ebili mmiri dị elu nke voltaji mwepụta ebili mmiri dị elu, mgbasa nke mwepụta ebili mmiri ọrụ na voltaji mwepụta ebili mmiri ọrụ
elu. Ihe njide Zinc oxide nwere ezigbo nzaghachi ebili mmiri nke voltaji ebili mmiri, na-enweghị oge, ihe fọdụrụ n'ọrụ ịda mbà n'obi, enweghị mgbasa nke mwepụta wdg.. A na-eme ka oke ebili mmiri dị elu, oke nchedo ebili mmiri ka mma
nke ukwuu, kamakwa na nhazi mkpuchi, enwere ike ịnwe oke ebili mmiri, àmụ̀mà, oke nchedo ebili mmiri ọrụ fọrọ nke nta ka ọ bụrụ otu, ka o wee nye nchekwa kacha mma maka akụrụngwa ike eletrik.
Ihe njide àmụ̀mà metal oxide nke ejiri ihe mejupụtara kpuchie, na-eji ịkpụzi ihe dị mkpa, teknụzụ mkpuchi abụọ, arụmọrụ mkpuchi dị mma, arụmọrụ ịgbawa mgbawa, ma nwee ike ibelata mmetọ ahụ
nhicha na-enweghị mgbochi ntutu isi mmiri, iguzogide mbuze eletriki, iguzogide ịka nká, obere olu, ibu dị mfe, ntinye na mmezi dị mfe. Porcelain bụ ihe eji egbochi àmụ̀mà maka
imelite ngwaahịa.