We found this circuit generates signals from 200 Hz to 62 kHz and can be used to repel mosquitoes and mosquitoes. The circuit can be powered from 2 small batteries to 9 V battery.
This effects circuit can be used with microphones or guitars. The circuit is from an American...
This circuit generates pulses whose frequency depends on C1. The circuit can be powered by...
I found this circuit in a 1998 publication, but as all components are common, it can be easily...