The post explains a simple mosquito electrocution net, or mesh circuit which can be easily built and installed on a home window for blocking and killing an in-surge of mosquitoes. The idea was requested by Mr. Ram.

Technical Specifications

Please help with any working circuit diagram for Mosquito, Insect Killer using Walton Voltage multiplier method. Output should be around 2kv. Wants to let it remain connected in ac mains like 'Insect Killer cum Night Lam' which are available on market but they are having 900-1000v in output and stop working in few days.

I tried to get help from Google but I am getting negative feedback most of the time. People are saying they getting dropped voltage at output. You have some circuit but they are battery operated and cant be remain on all the times.

Plz help with with a new topic on this Form.



The Design

In one of the earlier posts we discovered how conventional mosquitoes traps work by luring the insects through the generation of CO2 gas (by burning propane gas), and other other forms of agents such as octenol which imitate human respiration and human body odor respectively, and help to attract mosquitoes towards these artificially generated baits.

However since there's no easy way of manufacturing CO2 at home, neither is acquiring octenol for the same, attracting mosquitoes the usual way looks to be the most hassle free option.

The natural way is the manner in which we find the mosquitoes enter our houses everyday in the evening, by tracking the CO2 content generating by us in our house and also by the body odor that may be consistently present inside our homes.

Also since the entry path of the mosquitoes is usually through the windows, this entrance can be effectively used for installing a trap and for killing the insects.

The idea here is to position a set of steel meshes covering a particular selected window, and powered with a high voltage source. When the mosquitoes try to make their way through this window, they are instantly killed through electrocution between the mesh structures.

I have already discussed the mechanism and a working circuit of a mosquito zapper bat in one of my previous posts, which utilized a high voltage generator for electrocuting the insects trapped in the bat mesh. The present mosquito killer design is also based on the same principle and makes use of a high voltage across a window mesh for electrocuting the passing mosquitoes.

In one of the other posts we learned how to make a CDI driver circuit for generating high voltage sparks inside a vehicle spark plug.

Since the above concept facilitates an easy and quick way of implementing a high voltage across a given pair of terminals, we incorporate the same for creating the electrocuting arcs across a set of window mesh assemblies.

The following discussion shows how the mosquito trap or the mosquito killer mesh can be built at home for the suggested purpose.

Designing the Steel Mesh

Referring to the shown diagram the mesh assembly is built by fitting three identical sets of readymade fine iron or steel nets with a help of a few well fabricated square wooden frames.

After securing the steel nets within the wooden frames, these are tightly screwed together face to face using nuts and bolts and spacers such that the three frames acquire an optimized distance from each other.

The above assembly actually becomes the most tedious and the crucial part of the system and once this is completed, making the high voltage mosquito killer circuit can be rather simply done with the help of the following circuit.

The High Voltage Generator Circuit

In the above high voltage generator circuit, the IC 555 astable is used for feeding high frequency pulses to the primary of an ordinary 0-12V/220V transformer, via a switching transistor TIP122.

This generates the specified 220V across the other side of the transformer which is used for charging a high voltage capacitor via a network of rectifier diodes.

The accumulated 220V charge inside the capacitor is alternately discharged by an SCR circuit, such that the discharge voltage is dumped across the primary of a standard ignition coil transformer, commonly seen in motorcycles for generating sparks in the spark plug.

The induced 220V in the primary of the ignition coil generates a very high voltage across its secondary high tension wire.

This extremely high voltage is fed across the steel mesh, in the manner as specified in the first diagram.

The central mesh carries the hot end of the ignition coil, while the outer meshes are connected with the ground potential of the circuit.

The 22k of the 555 IC circuit is carefully adjusted such that the sparks do not fly off between meshes as long as there are no interfering elements between the meshes, but trigger thee sparks as soon as a "fly" or a mosquito is detected between the mesh assemblies.

The 100k pot must be used to regulate and produce the best frequency which may ensure reasonably cool running of the two transformers.

The circuit may be powered with any standard 0-12V/1amp adapter unit.

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