Schematic Diagram

This Insect Repellent Circuit Diagram produces a high frequency sound coming to ultrasound and adjust P1 serves to calibrate the ideal sound to scare away certain types of insects. It is based on a stable multivibrator in which the frequency is made ​​by the capacitors C1 and C2, which can be ceramic disc or plate, the resistors R2 and R3 and potentiometer P1.

The crystal is a type of transducer is piezoelectric, the current consumption of only approximately 7 mA ensures a good autonomy if the power comes from a 9 volt battery.