There are many ultrasonic pest repellent devices available on the market but a major drawback is that their power output is low and their effectiveness suffers. This electronic pest repellent generates powerful ultrasonic signals to repel pests.
In addition to the ultrasonic frequency oscillator built with CD4047, separate push-pull power amplifier (with 2N3055 or TIP31C) and transformer are used to boost ultrasonic signals. The output of the power amplifier is coupled to a tweeter through output transformer X1, which is wound over ferrite core (UU or CC core).
Primary winding consists of 150 turns of 20 SWG while the secondary winding is 40 turns of 24 SWG wire. Adjust potentiometer VR1 for maximum effectiveness.
This circuit has not been tested.
Caution! This is a powerful sonic pest repellent circuit so use it only in outdoor places. Do not use this ultrasonic pest repeller near babies or animal pets.