The advertising medium which uses electric current in bulbs is referred to as

The advertising medium you are referring to is neon signs. Neon signs are a type of advertising and signage that use electrified, glowing tubes or bulbs that contain neon gas. When an electric current is passed through the gas, it emits light, creating a bright and eye-catching display. Neon signs are popular because they are highly visible at night and can be customized in various shapes, sizes, and colors. They are often used for attracting attention to businesses or special promotions.