Working principle of a mosquito bat

Mosquito bats also known as electric mosquito rackets, are an effective tool against mosquitoes at home. It may be less effective against larger and fast moving insects like the common housefly. A mosquito bat usually has three layers of metal mesh. Central mesh is positively charged and outer meshes have negative negative charge. When the insect comes in contact with the positive and negative charged meshes simultaneously, circuit is completed resulting in annihilation of the insect. This is associated with a visible spark and a pop sound.

Mosquito bats are activated by the switch on their handles. The handle contains a rechargeable battery and a high voltage generator circuit. It is typically a DC to DC converter which generates a few thousand Volts. A simple bridge rectifier with voltage dropping resistors can be used to charge the built-in battery from mains supply. Voltage divider resistors can light up a charging indicator LED. After full charge, it can provide a few hours of useful operation. DC output of the battery is first converted to an alternating current using an oscillator based inverter. A small ferrite core step up transformer gives an output of a few hundred volts with a frequency of around 1 kHz from the oscillator. That is fed to a voltage multiplier circuit using diodes and capacitors to give the final output to the mesh. The device shown here has an LED flash light in addition.