The light-bulb emoji is encoded as Unicode character U+1F4A1.
U+1F4A1 is the hexadecimal code point for the character officially named ELECTRIC LIGHT BULB. It is commonly used for ideas, inspiration, invention, learning, or a sudden realization. The character is part of the Miscellaneous Symbols and Pictographs block, a Unicode range containing many pictorial symbols used in modern text.
The code point is not a description of one company’s graphic. A device may show a yellow bulb with a gray base, while another platform may use different colors or proportions. U+1F4A0 is DIAMOND SHAPE WITH A DOT INSIDE, U+1F526 is FLASHLIGHT, and U+1F4A5 is COLLISION, so visually related symbols should not be confused with the bulb character.