Written By: Mahmudul Hasan Shakil
I used here 555 timer Ic. for making a frequency .I also used here piezo buzzer,1.2k resistor and 10k variable resistor for increasing and decreasing frequency and two 10nf capacitor. From the calculation of astable mood we will get F=1.44/((1.2+2*1.2)*10nf)=39k HZ.
It will repel mosquito and another insects, which can’t tolerate this frequency.
Circuit diagram :