The sound you hear when you switch on a mosquito bat or a bug zapper is typically a high-pitched buzzing or crackling noise. This sound is produced by the electrical current flowing through the device's electrified grid or wires.
When the device is turned on, the high voltage in the bat or zapper generates an electric field that attracts insects. When insects come into contact with the electrified grid, they complete the circuit, resulting in a brief discharge of electricity and the associated buzzing sound.
In a quiet environment, you might notice a similar sound even when the mosquito bat or bug zapper is not in use. This is likely due to electromagnetic interference or electrical noise present in the surrounding environment. Various electrical devices and appliances can emit low levels of electromagnetic radiation or produce electrical noise that can be audible as a faint buzzing or crackling sound.
In most cases, this low-level noise is considered normal and nothing to be concerned about. However, if you notice any unusual or excessively loud sounds, burning smells, or signs of malfunctioning with the mosquito bat or bug zapper, it would be wise to discontinue its use and consult the manufacturer or seek professional assistance to ensure safety and proper functionality.