Peter; Just becouse it is resonant at 1MHz, does that mean that you cannot drive it at 50K? I bet it will drive, possibly with less efficiency. Just a guess. Chris Peter Lau wrote: > Hi, > > For a school project, I want to investigate the use of ultrasonic waves to > determine the state of various items of food (eg. fruit). > -- http://www.piclist.com#nomail Going offline? Don't AutoReply us! email listserv@mitvma.mit.edu with SET PICList DIGEST in the body