This repellent operates with frequencies from 30 to 45 kHz, serving for insects and rodents. The circuit is from 80s documentation. The transducer is a piezoelectric type.
Based on National semiconductor power operational amplifiers, uncommon today, this circuit...
We find this circuit in an 80's EDN. The circuit can be used with equivalent operational,...
This balance or balance circuit with phase inversion was found in documentation from the 90s....