A ballast resistor wani nau’in resistor ne na wutan lantarki da ake amfani da shi wajen kayyade yawan abin da ke gudana ta hanyar da’ira. Yawancin lokaci ana amfani da shi a cikin da'irori waɗanda ke buƙatar ci gaba na halin yanzu don aiki da kyau, kamar a cikin fitilun masu kyalli ko a cikin tsarin kunna wutar lantarki don injunan konewa na ciki. The ballast resistor yana aiki ta hanyar ƙara juriya ga kewaye, wanda ke rage yawan adadin da ke gudana ta cikinsa. Wannan yana taimakawa wajen hana lalacewar da'ira kuma yana tabbatar da cewa na'urar tana aiki cikin amintaccen iyakar aiki.