A long-standing debate about whether e-money from vile creatures, able to poison any summer activities do not cease. We decided to put my two cents in this case.
Scheme:
Everything is done on a single chip K561LN2 containing 6 inverters. On the elements DD1.1 and DD1.2 is assembled directly to the generator, everything else is an amplifier. The oscillator frequency varies from 10 to 30 kilohertz. As the piezo oscillator oscillator type SN-1 or SN-3, or any other, who will be on hand. Powered circuit from the source voltage of 9 volts. For example, battery "Krona".
Bourgeois analog circuits - CD4049.
Big request to all who will repeat the scheme to share impressions still it scares mosquitoes or not?
Publication: www.radiokot.ru, www.cxem.net