Hi You can indeed pick up the 32 KHz output of the crystal with a microphone. We used to do that and used the result to drive a counter. The information was used to manually (yes it once was done that way) set the watch modules on frequency.
Depending on the size and design of the crystal, the Q can be anywhere up to about 150K on a 32 KHz crystal. Some designs struggle to get to 50K. Bob > On Feb 7, 2016, at 7:31 AM, Tim Shoppa <tsho...@gmail.com> wrote: > > I know that the tiny modern 32kc/32.768kc tuning fork crystals continue to > produce output for a second or so after power is shut off. > > This leads to my guess that typical modern tuning fork crystals have a Q of > 30,000 or so. I'm not sure any manufacturer actually publishes Q for their > tiny tuning fork crystals but maybe from ESR and other crystal motional > parameters I could come up with some other way to derive Q from a modern > tuning fork datasheet? > > I wonder if I had a ultrasonic microphone if I could audibly pick up a > modern tiny tuning fork crystal. (My ears have never been good to 32kc even > when I was younger!) > > I remember when I was younger, I liked listening to the high pitched hum of > my dad's tuning fork Accutron (360Hz). > > Tim N3QE > > On Sat, Feb 6, 2016 at 11:17 PM, Morris Odell <vilgo...@bigpond.net.au> > wrote: > >> This is a very interesting discussion. I have experimented with some audio >> frequency crystals in the 3-6 kHz range. I don't know what they came out of >> but it was probably some sort of FDM telephony or telegraphy equipment. >> They're in the form of vacuum mounted bars with 4 plated terminals in tall >> 7 pin or octal tube envelopes. When suitably driven they oscillate audibly >> like a bell ringing and as a result of the very high Q they even keep >> ringing for a few seconds after the power is turned off. Unfortunately I >> don't have access to a stroboscope. I'd like to do something useful with >> them on display, perhaps a clock for people with presbyacusis who wouldn't >> notice the sound :-) >> >> Morris >> >>>> You have it right, iovane. At the least, they should be protected >>>> from light, >>>> thermal radiation, and emf. Won'drous things will happen if the >>>> crystal and >>>> its structure are subjected to radiation through the glass. I'd >>>> suggest a foam gator wrap in a tin can as a minimum. Put the >>>> oscillator cat in there too. >>> >>> I have a 100 kHz glass "Crystal Unit" made by G.E.C., type JCF/193 >>> with a serial number and sealed in a valve/tube with seven pins. >>> I removed it from my Eddystone EA12 that I bought from Tom Roberts, >>> G3YTO, SK 1985. It has a black shield with a spring inside at the top >>> so that it grips the base. The valve that produced 100 kHz markers for >>> dial calibration failed and I don't use the EA12 these days. >>> It will be interesting to see how stable it is and what the effect of >>> light and heat on it is when I start experimenting. >> >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.