Most of the electronic pest repeller circuits have a major drawback of low power output hence their effectiveness suffers. The ultrasonic pest repeller circuit described here generates powerful ultrasonic signals therefore efficient to repel pests like mosquitoes. In addition to the ultrasonic frequency oscillator, we use a separate push-pull power amplifier and transformer to boost ultrasonic signals.
|Circuit diagram of Powerful Pest Repeller: Click on image to enlarge|
Ultrasonic frequency oscillator is built around IC CD4047. This IC provides complementary outputs. These complementary outputs are amplified by transistors T1 and T2 (BD139) to drive transistorised push-pull power amplifier stage comprising power transistors T3 and T4 (2N3055).
A tweeter is used to produce utrasonic frequency sound to repel pests. The power amplifier output is connected to the tweeter through transformer X1. Transformer X1 is wound over ferrite core (UU or CC core). Primary winding consists of 150 turns of 28 SWG while secondary winding comprises 40 turns of 24 SWG wire. Adjust potentiometer VR1 for maximum effectiveness.