Here is the circuit diagram of an ultrasonic mosquito repeller.The circuit is based on the theory that insects like mosquito can be repelled by using sound frequencies in the ultrasonic (above 20KHz) range.The circuit is nothing but a PLL IC CMOS 4047 wired as an oscillator working at 22KHz.A complementary symmetry amplifier consisting of four transistor is used to amplify the sound.The piezo buzzer converts the output of amplifier to ultrasonic sound that can be heard by the insects.

Circuit diagram with Parts list.



  • Assemble the circuit on a general purpose PCB.
  • The circuit can be powered from 12V DC.
  • The buzzer can be any general purpose piezo buzzer.
  • The IC1 must be mounted on a holder.


  1. Satya Brata Dutta

    I think easy to test the circuit whether functioning or not is possible easily. Take multi meter on 10 volt AC range with series a capacitor of .01 mfd disc type and measure on the point where pizzo point connected . If the meter deflect then it is functuionin.

  2. Mudassar Qadir Ahmed

    Hi sir,
    Is circuit able to repel both male and female mosquito ??

  3. shifralin

    i want to knw complete information about tis project sir and cost .whether its easy to complete ah sir

  4. Kind of new at this. The sk and sl 100 transistors? IS there a part number or other Identification? I can’t find anything by those numbers.

  5. i want to know the complete information(working) about all the components used in this circuit

  6. Åsmund Enget

    Hello, Im an norwegian engineer-student, and I am having your circuit as a project, both making and attempting to explain it. Making it wont be that much of a problem, but understanding it is a little more tricky. I wondered if you could explain a little bit how/why you have used 4 transistors, for example, and why this circuit will work the way it does.

    It would mean a lot to me!

    And, could you answer me by mail by some chance?
    On beforehand, thank you.

    • Seetharaman

      Hi This is called bridged push pull output. This circuit will provide 4 times the normal 2 transistor push pull output connecting through a coupling capacitor. IC 4047 is an oscillator whose frequency is set by R1 & C1. The complimentary output of the IC which is available on pin no 10 & 11 are fed to the bridged output circuit. Since the frequency used for repelling mosquitoes is in the ultrasonic range a piezo transducer, which respond to Ultrasonic sound better is used for producing sound, instead of standard loud speaker.

  7. shivshankar yadav

    Thank u very much sir…from today I started working on this project…

  8. neha jadon

    I want more information about electronic mosquito repeller

  9. Dear sir also I used c1 as 4.7 but in true I’m not sure is it 4.7nd or 4.7pf
    Also the R1 I can’t find 1k ohm accuracy I connect one to the circuit but when I measure it I found it 7.8k ohm

  10. Hi dear sir
    The circuit it so good but
    I replaced the piezo buzzer to tweeter transducer 8 ohm
    Is this will work or not
    Other thing when I tested the circuit the Q1 and Q4 were so hot
    Is this normal or I have problems in circuit

  11. Goitom haile

    The mosquito project is nice please, explain how to make the circuit?

    • Seetharaman

      Hi Goitom the construction hints are clearly given in foot notes just below the circuit diagram.


    plz send the electronics circuits to my mail up to date

  13. Hai sir ! mosquito repeller project is nice ,circuit diagram is it here but how the circuit is working please explain it? what is the application of this circuit

  14. santosh shah

    can we use transformer 12-12 v .or for 12 v supply dc,we use 12 v battry….what if we use 9 v dc battery..please send me answer…and help me out 2 make complete project

  15. Terrence Banister

    We’re a group of volunteers and opening a brand new plan in our little local community. Your website offered us with beneficial info to work on. You have done a striking position and our complete community shall be thankful to you.

  16. sir,
    iam a second year student.does this project works well?
    what is the use of this circuit?
    could you please tell as early as possible

  17. Sana Naseer

    which type of output waveform will appear on oscilloscope?

  18. seetharaman

    Hi Tank you can connect an oscilloscope and see the waveform

  19. Tank Parag

    Hello sir ,can i remove the buzzer and check the frequency on CRO ???

    • Mudassar Qadir Ahmed

      You can remove the buzzer and check the frequency on Oscilloscope.

  20. Electronics Projects

    CD4047 has very good applications. Oscillator function of Cd4047 is Damn good.My Suggestion is Better to use RPS with output 12V D.C for regular use at home because battery not stands for long time .

  21. Lijo joseph

    Can we replace the 4.7nf capacitor to any other capacitor

  22. I like this electronic mosquito repeller. . . . i want more detail about this project……. please…..

  23. the circuit part are not fully give with the need

  24. I connect the circuit as it is ……. But it not working properly… Why it so happened????????

    • i think thr ll b some loose contacts …… better disconnect n try it again bcoz i got the result ……… try it once more

  25. Priyadharshini

    hi.i used piezo buzzer and we didn’t hear any sound,is there any alternative?
    also instead of mosquito’s what can we use to test this experiment.
    very urgent please reply.

  26. Will this circuit scare of the squirrels?? i dont want that to happen.

  27. hi sir can i use speaker instead of piezo buzzer and if any new schematic diagram please send to my email address my email adderss is

  28. seetharaman

    Hi Zunnur there are so many makes available. you can use the one meant for car stereo add on tweeters two small one comes in a pack. clarion etc.

  29. Thanks for the ckt diagram.Would u please inform me the model number of the piezo tweeter available most in market.

  30. seetharaman

    Hi Susan connect 4.7nF in parallel to C1 the oscillator frequency will be in audible range. now check any out put is there if not check all the components and IC pin connections. if it gives audible sound, remove the capacitor connected in parallel, the circuit is ready for use. Piezotransducer will emit the in audible signal of the oscillator. sound level indicator is an equipment to measure the sound level (noise level) in an environment. they operate in human audible range only.

  31. sir,we want a method to check the circuits. what about that piezo transducer or that sound level indicator?
    can you please explain this? can that be used to check the circuit?

  32. Khurami_45

    this circuit is is a good achievement for insect specially mosquito if u will use the right component then no problem circuit will work i also checked it

    • Electronics Projects

      No need of 16f877a. CD4047 is enough because it is simple and low cost and works well as Oscillator.

  33. Nice project..How far the ultrasonic frequency can reach…

  34. nice project many square meter can reach the ultrasonic frequency

  35. seetharaman

    Hi Annalisa you can use BC337 / BC327 for SL100 / SK100. or the latest 8050 /8550 coplimentary transistors

  36. hi.i used piezo buzzer and we didn’t hear any sound,is there any alternative?
    also instead of mosquito’s what can we use to test this experiment.
    very urgent please reply.

  37. ginawa ko kaso pumutok yong bc337 o SL100 ko n transistor ng sinubukan ko

  38. Sahid tunde

    Pls i need a cct diagram 4 rat repeller and details on the working principles pls…its very urgent

  39. i need to build wall avoider robot with out microcontroller
    pls help

  40. already we knew that the human audio freq range is 20 to 20000 can u say that ultra freq range wont affect human. .kindly please explain that

  41. james Holy

    please can you list all the components that are use and their specification,my school approved this as my project.

  42. Electronic Mosquito Repellents Don’t Work, Say Researchers
    ScienceDaily (Apr. 18, 2007) — Electronic mosquito repellents — buzzing devices marketed to prevent malaria — don’t prevent bites and therefore don’t prevent disease transmission, according to a new review of studies. . . is this true

  43. seetharaman

    If you use R1 as 22K and C1 as 10PF tha frequency out will be 1000kHz, similarly for 10 kHz C1 should be 100pF and R1 should be 220k or 22k and 1000pF. for 20kHz either you make C1 half (500pF) the value or R1 (11k)half the value(as the formula is inversely proportional)

  44. Hi Seerharaman,
    May I know what is the formula calculation for this result as you mention? How we calculate it? Thanks. Seetharaman.
    A 1000 kHz 22k 10 pF
    B 100 kHz 22k 100 pF
    C 10 kHz 220k 100 pF
    D 1 kHz 220k 1000 pF

  45. seetharaman

    Hi Phuah
    Freq R1 C1
    A 1000 kHz 22k 10 pF
    B 100 kHz 22k 100 pF
    C 10 kHz 220k 100 pF
    D 1 kHz 220k 1000 pF
    The above is the data for CD4047. From this you can calculate.

    • will piezo buzzer create any sound which we can hear or not

  46. Actually what range of the output frequency can be generate by this circuit? How we calculate the output frequency? Got any calculation formula? Thanks.

  47. seetharaman

    Hi Phuah it should be ok as we require the frequency around 18 to 22kHz to drive them.

    • menace nditi.Tanzania,East Africa.

      I am confused with this circuit if I want the output frequency to be between 20khz and 30khz what values of R and C should I USE?????

  48. admin


    C2 is an electrolytic capacitor and they are available in different voltage ratings, from few volts to hundreds of volts and thats why its a common practice to represent the voltage rating of electrolytic capacitors in the circuit diagram.

    C1 is a ceramic capacitor and the commonly available ones are rated from 50V to 400V. Some manufacturers represent the voltage rating using some code while others not. Any way we can guess that a commonly available ceramic disc capacitor will be rated at least 50V or so.

    Here the working voltage is 12V and a 50V ceramic capacitor will be more than enough.

  49. Hi Seetharaman, thanks for your respond. Can this circuit work with Piezo Tweeter with 98bd, 20khz. Is it workable to repel the mosquito?

  50. Hi Seetharaman, may I know what type of the output speaker is most effective for pets repellent? How can I make a frequency for all range of pets include rat,mosquito, mice and spider? Thanks.

  51. seetharaman

    Hi Bhaskardev piezo tweeters are the only inexpensive device which can respond to high end of sonic frequencies.

  52. bhaskardev

    can piezo buzzer :can produce that much frequency in 20khz range

  53. seetharaman

    Hi Zaman these small speakers may not respond beyond 11 to 12kHz. only hi-fi tweeters can respond they will be quite expensive. Hence Piezo tweeters are quite in expensive. this is normally used as additional attachment with car system speakers or part of portable sound system. you can use them.

  54. Hi Seetharaman
    Can I use table clock mini speaker instead of Piezo Buzzer?

  55. Hi it may repel the mosquito but does it affect the pets like cat and dogs becoz It shold not affect my doggy

  56. Ravendra Singh

    can i use 20khz mp3 file played on speaker?

  57. What is the Cost of the IC and the 4 transistors …Pls tell me approximately!!

    • Electronics Projects

      you will get total components in the circuit at below Rs.25

  58. vishwanath

    Dear sir,
    I am a chemical engr by profession. I need an electronic mosquito repellent which may be powered by 9 volt battery, for my personal use in travelling.
    I assembled mosquito repellent circuit. I am observing, mosquitoes are not affected by this. I don’t know whether the circuit is working or not. I used a piezo tweeter which works with 8000+ frequencies which I can hear (in other tests). I want to know where to be connected with No 2 leg of IC 4047. Can you please suggest me in this regard?
    If it works, I want to assemble few more for our use. Can you suggest me how to make a mosquito repellent with Variable Frequency (from 16 kHz to 45 kHz+) with sufficiently powerful output so that it should be sufficient to a 30 X 40 house. Or can you prepare me one such piece?

  59. There are also insect repellent products available based on sound production, particularly ultrasound (inaudibly high frequency sounds). These electronic devices have been shown to have no effect as a mosquito repellent by studies done by the EPA and many universities.

    Copied from:

  60. Thanks alot for the cct! But my question instead of ic,can one use multivibrator circuit to generate the frequency! Since T(time const)=RC and we know that F(freqency)=1/T.We just make capacitor const and increase our resistor value to generate 20khz and above.Then connect output of our NPN collector with ultrasonic transmitter! Can it work that way?

  61. Hi Seetharaman,
    Thanks for reply. Can u do me another favour by telling the number of resisters used and the specifications of resistors.If there is any diode used please tell me the numbers and specs.

  62. Seetharaman

    Hi Fahad the number of transistors are 4 and IC is one. The transistor are SK100 PNP general purpose transistor. SL100 NPN general purpose transistor. you can use the recent types 8050 for SL100 and 8550 for SK100.

  63. Hi Seetharaman.
    please tell me the number of transistors used in this circuit and value of these transistors.

  64. Seetharaman

    Hi sourov Badeekh is correct it is a variable resistance to change the frequency of oscillation.

  65. Hi Sourov, its not a thing to be confused, clearly, its a variable resistance.. n Thx Seethharaman!

  66. is R1 a relay or resistance or variable resistance? i am confuse. plz help me.

  67. Seetharaman

    Hi Badeekh it should be 40KHz and it may not work. the response should start from 20kHz

  68. Thx Sir, i bought the components today, just last thing, i got 40MHz ultrasonic transmitter, is it ok?

  69. Seetharaman

    Hi Badeekh you cannot use piezo buzzer they have built in electronics for producing music or sound. piezo transducer or piezo tweeter. you can use ultrasonuc transmitter (sender transducer), ensure that they are capable of reproducing from 20kHz.

  70. Hi Seetharaman, m going to assemble it, just confused about the sound source, shoud i use simple piezo buzzer or the ultrasonic transmitter available in market?

  71. Seetharaman

    Hi Moon CD4047 is a standard CMOS digital chip freely available. For SL100 you can use BD135, BD137, BD139, 2N1711, 2N2219. For SL100 you can use BD136, BD138, BD140. 2N2905

  72. What is the subsitute for this IC, and the transistors ?

  73. Many researcher says that Electronic mosquito repeller doesn’t work. Is it true?

  74. please add the circuit diagram using NE555, because it’s not easy to found IC1 CD4047.

  75. Seetharaman

    Hi Hider since the frequency generated is beyond our hearing it will be difficult to hear, but you can make a sound level indicator using a condencer mic with suitable electronics.
    Piezo transducers can respond from around 1kHz to beyond audible range. they are normally used as tweeters in hifi loud speaker systems.
    Car reverse horns musical chime electronic music generators use them as they are wheather proof and they contain no moving parts like magnetic voice coil loud speakers

  76. can we detect this ultrasonic wave sound produce in this circuit
    2.does piezo buzzer produce any sound

  77. hi frds i am bujju. Now i am studying D.E.E.E i want to improve my electrical and electronics pls any one help me contact me into my mail id Pls help me

    • Hello Buju,

      Browse through all our articles. You will gain good knowledge.


  79. Seetharaman

    Hi Ravovan they are low current type bc326 327 can be used

  80. Radovan Skalamera

    can I use transistors BC556 and BC546?


  81. Sethumadhavan

    Hi! Did anybody tried? Is it really working?

  82. Sethumadhavan

    In what room size the circuit works, 10×10, 15×20,….?

  83. Seetharaman

    Hi Haris if you remove the transistors IC may not be in a position to drive the Piezo tweeter directly.

  84. Seetharaman

    Hi Pooja the sound produced by this device irritates them and they become either sluggish or defunct or try to fly away. Thus they are driven away from the visinity.

  85. another one question, if we remove 22 mf capacitor then what will happen? and is the piezo buzzer is the example of piezoelectric sensor?

  86. thanks for the circuit… but i want to know how the ic cd4047 works in this circuit(does if change the electric signal to sound signal)…and does variable resistance change the output frequency..
    plz reply me.. as soon as possible….

  87. Seetharaman

    Hi Senthil the ultasonic frequency range is just beyond human hearing range of 20KHz to 100KHz. There transducers available for sender and receiver. you can use them with amplification and detection and convert into signal strength with a DMM in Volt/mV range.

  88. very nice and useful circuit.can u pls tell me how to check the ultrasonic there any such circuits avilable?

  89. Seetharaman

    Hi Biomer you can use NE555 timer IC with one transistor and tweeter. There is no equivallent for CD4047 it is a standard digital ic.

  90. Thanks your share.
    What is the CD4047’s alternative for this circuit.


  91. Seetharaman

    Hi Prakash you can use 16 ohms tweeter or two 8 ohms tweeters in series.
    Hi Firoz assemble this try using it near the group of mosquitos, you can see the reaction of them. you also see my aug 30th comment

  92. Pl. tell me, instead of piezo buzzer can i use any speaker. If yes pl. give me idea.

  93. Seetharaman

    Hi Isuru 4.7n will be written as 472 and voltage will be written in 63V etc if it is Japanese it will with J etc for voltage, here 16volt and above capacitor will do.

  94. Isuru(SL)

    Is this C1 4.7nF having no such working voltage? like 102, 103…

  95. kesavan.b

    i happened to see your article in the site. i am 60 now. about more than 20 years back i was testing such articles as a hobby. now due to over age and due eye problems i am unable to do any work.

    will you kindly assemble one and send me for my household use, because we are suffering from heavy invasion of mosquitoes at our city. further the use of chemical repellents make my asthma problems more aggravated and throw me to admission to hospitals for emergency attention.

    i am ready to send the cost in advance if you can kindly mail me the details. rather if it is at market it may please be informed.

    thank you very much for your publication.
    i further wish you to develop many projects which are needed for the people’s welfare and publish such in the website.

    thank you one again and expecting your reply.
    kesevan. b

  96. Seetharaman

    Hi Shubam it is safe for humans and dogs as dogs listening range extends upto 25KHz. Hence this is quite safe

  97. i need the cost and some video of making this…………please

  98. pls i need full detail about this repeller and how it work and if i want to build it the capacity of the componet i wil use thank you GOD blessed you.

  99. pls i urgently need a workable simplified circuit diagram for mosquito repellant without any ic. please forward it to my mail I will appreciate it better it many different circuit can be forwarded. Thank

  100. whats the voltage capacity of capacitor C1 (407nF)

  101. hi…… thanks for this circuit but tell me what is the voltage of capacitor C1 4.7nF or else can use any other capacitor?


    hi,I want to assemble this really working.What is its renge?how many meters is its range?reply urgent pls.thank you

  103. what is the use of the 10k variable resistor and what should be the correct resistance tune for the variable resistor?

  104. seetharaman

    Hi Vignesh This circuit is based on the simple principle that insects gets immobilised or driven away by using ultrasonic sound above 20KHz. The above circuit operates around 22KHz. You can try by assembling and try to direct it towards the group of mosquitos, you can see the results for yourself. K1 should be Phiezo tweeter (used in two in ones for hi frequency reproduction).

  105. realy is it usefull? i want full explanation about that circuit?

  106. Godwin.Plant a few mosquitoes in the bottle and look at their reaction

  107. chandrasekhar


    i would like to get the rodent reppeller circuite

  108. After completion the circuit How will I understand that it is working properly?

  109. seetharaman

    Hi Wandera the cockroaches will not respond to electronic sounds. chemicals are the best solution for them, the combination of which should be changed regularly – immunity problem.

  110. Hi ,apart from mosquito ,can we get alternative for cockroaches .


    Hi!!! Is there any replacement for the IC?? Can i use any other IC other than CD4047?

  112. seetharaman

    Hi Pablo the transistor can be any medium power low frequency silicon transistor. Vceo 24 volt Ic 500mA Ptot around 1 watt hfe around 100 at 100mA Ft 1MHz

  113. please what is the specification for the transistors for the mosquito repellant circuit

  114. seetharaman

    Hi Sonny you can try to assemble a variable frequecy oscillator in the range of 16 to 20KHz with a suitable amplifier and a HF transducer(ceramic tweeters. This range will affect only mosquitos not other living things. You can find out at what frequecny the mosquitos flie away as your sounder approaches them.

  115. Thank you for the info, is there any alternative circuit(for mosquito repeller) that i can use in our piggery that will not affect my dog?

  116. seetharaman

    Hi Sonny with pigs it should not be a problem with dog you will have lots of problem as they can hear it.

  117. Is this mosquito repeller can be use in our piggery? we noticed our pigs had several bites from mosquitos.
    Since this circuit is operated in sound frequency above 20khz range, would there be any side effects in our pigs?

  118. seetharaman

    Hi Asad FOR SK100 2N2905, BD136, BC327 for SL100 2N1711, BD135, BC337,
    Hi Adnan for this low power radiation at 22KHz will not have any effect on human health.

  119. its a safe device or is thee any side effect of 22khz frequency to human health?

  120. Is there any alternative transistors for Sk100, SL100

  121. seetharaman

    Hi Digonto yes you can. 12 volt 100mA is sufficient.

  122. Can I use a transformerless power supply(12V 100mA)for this circuit ?

    – Thanks

  123. I need a 1kva inverter circuit a full explanation of it, thanks.

  124. Thanks for your circuit .is there any replacement for the transistors

  125. IS this circuit really repelling Mosquitos effectiviely

    • Atharva.muraskar

      I want more information about this project and how to attached a speaker to this project?????