1.Bug zappers work by emitting a UV light that attracts bugs to the center of the device, where they're electrocuted, usually between two metal grids. Because of the irresistible lure of their light, bug zappers are incredibly effective at killing bugs.
2.An ultraviolet emitting light bulb attracts insects into a high voltage electrical wire mesh grid where the bugs are electrocuted. The light bulb and the wires are housed in a protective plastic or grounded metal cage. Most Zappers use fluorescent light bulbs that emit ultraviolet light to attract the insects