There are these types of mosquito killer racket are easily available in market at some 150 rupees.
This consist an electric fence in the bat portion which has 5000-10,000 volts passing through them. This is not only mosquito repellent, it’s insect zapper. When a mosquito gets in contact the high voltage burns it. The inner circuit consists of battery, a charging unit, and a HV inverter circuit, which I’m going to describe here.
Coil turns will be as described in text and not the one indicated in this tmage.
The circuit consists of a flyback topology transformer driven by a general NPN transistor 2SD965. The feedback coil of transformer is of 10 turns, the primary is of 40 turns and the output or secondary coil is of 450 turns. When this circuit is run by 3Volts, the transformer generates about 2000-4000 volts at zero load, and the output is then coupled 3 times by using 3 IN4007 diodes and suitable capacitors, thus reaching our need of 5000-10,000 volts.
Note: All diodes used in circuit are IN4007 diode, The transistor is 2SD965, and can’t be replaced by BC548, The transformer should be ferrite core.
Below an actual circuit board found in mosquito zapper rackets.
I purchase new mosquito bat(same ckt mentioned above)last week. Last few days its not charging fully, if i confirm with metallic screw driver points, initially only it shows some spark (short with outer and inner net).
Can you guide, the steps to trouble shoot the electronic parts if any.
regards
Laxman
Replacing battery may be the correct choice as the batteries that comes with the bat is relatively poor built.
Thank for details ,but Can this circuit switched on continuously at no load condition Pl. suggest
Yes, it can be.
Nice explanation Arup , I always wanted to build a small electric shield for a window using this bat circuit.
Can you tell me the transformer specs that i need to tell the shop guy , used for a bigger circuit.
from the previous comments , i see its bigger transformer and higher capacitor that i need to buy. Anything else that is different than this circuit i need to note ?
With that you also need higher power rating transistor too.
Else just buy this kit, and connect the capacitor coupler circuitry at the output which should be fine.
Sir
I am from Cochin, the most famous place in Kerala for mosquito (Farming ) We have tried many ways like bat, fumigation etc, by evening around 6 pm the attack starts. The moment we open the door, a battalion will enter into the rooms and it is difficult to avoid them. I would like to know , like the concept of the bats, is it possible to fix net in front of the door with electric current passing like in Bats. if so , how can we make it.
Your suggestion very much appreciated
Thanks and regards
Najumal Hussain
Yes,
That's possible with this circuit.
My racket did not recharge properly. On opening it is found that there are two batteries side besides. Assuming it may have outlived its life, I purchased two new batteries but being a lay man does not know as to how to club these two( + _ etc) and solder it with the main circuit. I have a soldering device. Can you please explain how to go ahead as explained above.
further to my above comments dated 16 May 2012 I shall add the batteries are general 1.5V each and are rechargeable.
Yes. Try to connect them as it was before and it should work.
if primary coil has 12 turns and secondary turns is 450, that gives a transformation ratio of about 37, you say input voltage is 3v, multiplying input voltage by transformation ratio gives 111v but you say the circuit produces 2000-4000v, how is this possible?...thanks
The highest voltage is produced at the spikes. A 3V output transformer can also product 100V from 3V line with 3V applied.
do you have a ready pcb for the same with components. I wll be using 3.6v battery.need to do some trials
Thanks
No.
Hi Arup I purchased a New mosquito trap few days before. It worked fine for 2-3 days then after that it does not produce much spark to kill the mosquito.. i changed the batteries with new one but the problem is same... The charging light works fine and the green light on pressing the button also works fine.When i touch the fence using my car key only little spark is produced. Please tell me in detail the fault and which part is need to be replaced and the estimate cost of the new part..if possible please refer the answer with the diagram.....Thanks in advance
Possible the battery is faulty. Replace the batteries. You can try charging batteries externally using an adapter and try also.
Pl. tell which type of rechargeable battery suitable for the mosquito bat?
Ramesh
2xAA rechargeable battery pack.
Good day Arup, pls I need a solution repairs for my mosquito racket. I bought one and it spoiled after 2 weeks of use. so I but the second one it also stop working too. when I press the power key, the light shows and making the oscillating sound. But it does not make any spark to kill the mosquito. What do I do to repair the two Rackets? I am an Electrical/Electronics student. Pls send me solution to my email. Thanks
Well, check output capacitors and the battery. Since you're hearing the oscillating sound, transformer and driver transistor should be OK.
Osillating sound is present when switched on. i have checked the transistor with multimeter n found ok (shows 0.543 ohm on colectr & emitr) & impedance of driver transformer FB coil show 2-3ohm , pri 159ohm, sec 543ohms, is it correct?.
another transformer shows FB coil show 2ohm , pri 159ohm, sec 195ohms, is it correct?.
pls advise as i am tired bankrupt by buying 8 rackets in a year.
thanks
further to my post, batterries are ok, capacitors & diodes in out put are ok. led indicator does not light when tranformer is present in ckt, but when removed, LED glows good. All resistors are also ok. pls help.
thanks
what is the frequency of its out put?can i increase the frequency?
The frequency value has nothing to do with it's work.
Hi Arup,
thanks 4 expressing knowlege and i deep one in this mosquitoes and insect killer racket circuit issue. any i think i was the first to hatch the idea of such technology but because i'm not knowlegable in physics and science i could not do much. But now i have an innovative idea that could take this technology to the highest level in terms of profitability in the world market,, and i need people like work on it. can you be my guest in this multibillion dollars money making opportunity?????
Sim
OK. Start the business, then contact me.
Hi Arup,
very nice circuit. have you counted the exact number of turns of the transformer or is it just a guess?
thanks
Hi Arup,
very nice circuit. have you counted the exact number of turns of the transformer from mosquito racket or is it just a guess?
thanks
I think, I have counted by disassembling one.
Hello
I want to increase out put power upto 1600v to 2000v
I have a mosquito killer racket which have 2.4v 600ma battery inside
if I replace 2.4v battery to 5v than what happen ?
If you use 5V battery, more voltage will be produced but keep in mind that some capacitors may not tolerate and blast due to the high voltage.