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.
The time constant for this circuit found in a 1973 publication is given by R and C. The shot is...
Used with old projector films, this circuit found in Signalite documentation from the 1980s,...
This circuit generates damped sounds imitating a drum or other percussion instrument with...