Ultrasonic energy generator.

摘要

Leaks or thin spots in containers 10 are detected by an ultrasonic energy indicator that includes a modulator 22 that heterodynes ultrasonic signals received by a transducer 14 and creates an audio signal related thereto. The transducer includes a series arrangement of piezoelectric crystals 14 feeding a field-effect transistor amplifier 16 and the modulator operates in an amplitude modulation, suppressed-carrier mode which can be stabilized by a feedback loop. For indicating the presence of the audio signal, either headphones 26 or a meter 38 or both are employed. When leaks in a container are being detected, an ultrasonic generator is used which varies its output frequency slowly over a band of frequencies.