Bug zapper

A bug zapper, more formally called an electrical discharge insect control system, electric insect killer or (insect) electrocutor trap, is a device that attracts and kills flying insects that are attracted by light. A light source attracts insects to an electrical grid, where they are electrocuted by touching two wires with a high voltage between them. The name comes from the characteristic onomatopoeic "zap" sound produced when an insect is electrocuted. Bug zappers are usually housed in a protective cage of plastic or grounded metal bars to prevent people or larger animals from touching the high voltage grid. A light source is fitted inside, often a fluorescent lamp designed to emit both visible and ultraviolet light, which is visible to insects and attracts a variety of them. Newer models now use long-life LEDs to produce the light. The light source is surrounded by a pair of interleaved bare wire grids or helices. The distance between adjacent wires is typically about . A high-voltage power supply powered by wall power is used, which may be a simple transformerless voltage multiplier circuit made with diodes and capacitors which can generate a voltage of 2 kilovolts or more. This is high enough to conduct through the body of an insect which bridges the two grids, but not high enough to spark across the air gap. Enough electric current flows through the small body of the insect to heat it to a high temperature. The impedance of the power supply and the arrangement of the grid is such that it cannot drive a dangerous current through the body of a human. Many bug zappers are fitted with trays that collect the electrocuted insects; other models are designed to allow the debris to fall to the ground below. Some use a fan to help to trap the insect. Bug zapper traps may be installed indoors, or outdoors if they are constructed to withstand the effects of weather. However, they are not effective at killing biting insects (female mosquitoes and other insects) outdoors, being much more effective at attracting and killing other harmless and beneficial insects.