On Thu, 17 Sep 2009 09:18:32 -0500 "Derward Myrick" wrote: > I do not know how they are cut but I have a couple of > one kc crystals. They are rather long and if you thump > the unit with your finger you can hear it ring at 1 kc. Wow... 1 kHz? Those must be decanters to enjoy a good glass of wine in ;-) Note that if those are really xtals, it's probably the mounting springs you are hearing. The (older and larger) quartz stones are generally mounted between springs. Nothing to do with the actual piezoelectrical resonance frequency, of course. I actually found an antique one, which I suspect is 10 kHz (glass tube about 10 cm long, 1.5 cm diameter) John -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist