Lets talk about quartz

Thread Starter

Wendy

Joined Mar 24, 2008
21,914
I am bored out of my skull. I have decided to bring up various topic some people might find interesting.

I have had stroke

Today I'll talk about quartz. A truly remarkable material Quartz generate an electric field when put under pressure.It is a natural transducer. The little spark in a lighter when you click is a result of small spring loaded hammer slapping a small piece of quartz.The property is called piezoelectric. and used in every thing from earphones to crystal oscillators. Indeed it is the crystal in crystal oscillator.One of the early schematics I learned when I was first starting out looked some thing like this. Now I don't like the bias scheme but it works.I used ia CB (27Mhz) crystal and a 2N2222. One of my favorite transistors. The design puzzles me a little because the crystal has to invert the signal to work. A crystal is a complex mix of series resonant characteristic and a parallel LC circuit equivalent.

crystal.png
 
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wayneh

Joined Sep 9, 2010
16,129
One odd thing abound quartz is how ubiquitous it seems. Sure, you find it all over when hiking in the Rockies, but my son-in-law just found a nice 3 lb sample in a local (upper Midwest) park. It's really cool stuff with lots of applications, like diamonds or gold, and yet easy to find.
 

#12

Joined Nov 30, 2010
18,167
I had a dose of that memory hole a week ago. I could pull up things that happened 50 years ago but I couldn't remember 5 minutes ago and I couldn't find the words I wanted to say. A few days in the hospital and I'm about 95% OK right now. I have also been bored out of my skull, if you remember the squished disk I had 3 years ago. An MRI last week shows it as 90% healed.

I know, this isn't about quartz because I don't know squat about quartz except what it looks like in the wild. I wanted to say I know some of what you're going through. If you think this belongs in the "stroke" Thread, that's OK with me.

Keep rolling that rock up the hill. It's what we do.
 

#12

Joined Nov 30, 2010
18,167
I'm willing to bet you do'n't miss that a bit
I'm still not quite right in the head, but I'm close enough that I'm not afraid it won't come back.
As for the squished disk?
That certainly showed me that broken bones are minor compared to nerve damage! (Including brain damage which I include in the word, "nerve" because a brain is just a humongous group of nerves, neurons, and their connections.)
 

Kermit2

Joined Feb 5, 2010
4,163
Try singing simple nursery rhymes Wendy.
It seems silly, but using the facts you want to remember and putting those words to a well known song (Mary had a little lamb)
activates other areas of the brain and helps tag the facts to something already remembered making recall easier.

Interesting fact. The area of the brain that shows the most activity when you listen/think about music is the same structure that activates when you speak or read written words, only it is in the opposite brain hemisphere.
 

#12

Joined Nov 30, 2010
18,167
Ah yes, from the TV show, "House". Music is a global function. Therefore this patient couldn't possibly fit the diagnosis because he can respond correctly to a musical cue. And from Kermit2, try to engage global functions. That is your best method to kick your neurons back into activity. Number Twelve understands why Kermit2 is correct.:)
 

wayneh

Joined Sep 9, 2010
16,129

atferrari

Joined Jan 6, 2004
3,584
I recall seen, 50 years ago, a radio ham modifying the frequency of a crystal by carefully polishing it on a glass, using kitchen cleaning powder with few drops of kerosene. 8 fashion movements were very gentle. The quartz itself was VERY thin, prone to break. A big pluggable holder used in a transmitter. Cannot recall the frequency range.
 

cmartinez

Joined Jan 17, 2007
6,647
One odd thing abound quartz is how ubiquitous it seems.
Ubiquios, you say? ... it's more than half part of ordinary beach sand!



"... the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz."

I've been to all three beaches listed in that table, btw :)

And Wendy. I'm glad to hear you're bored out of your skull... it means that you've got more energy than you can handle, and are making important progress! ... take good care of yourself.
 
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cmartinez

Joined Jan 17, 2007
6,647
I am bored out of my skull. I have decided to bring up various topic some people might find interesting.

I have had stroke

Today I'll talk about quartz. A truly remarkable material Quartz generate an electric field when put under pressure.It is a natural transducer. The little spark in a lighter when you click is a result of small spring loaded hammer slapping a small piece of quartz.The property is called piezoelectric. and used in every thing from earphones to crystal oscillators. Indeed it is the crystal in crystal oscillator.One of the early schematics I learned when I was first starting out looked some thing like this. Now I don't like the bias scheme but it works.I used ia CB (27Mhz) crystal and a 2N2222. One of my favorite transistors. The design puzzles me a little because the crystal has to invert the signal to work. A crystal is a complex mix of series resonant characteristic and a parallel LC circuit equivalent.

View attachment 127025
Questions:
  • Does that circuit really output a sinusoidal wave as it seems in the diagram?
  • Does it mean that the crystal has some capacitive component to it too, or is the sinusoid being produced by the piezoelectric properties in the crystal itself?
  • What would it take for that circuit to output a square wave (other than the addition of a comparator) ?
 

#12

Joined Nov 30, 2010
18,167
Does it mean that the crystal has some capacitive component to it too,
nsaspook posted (#8) a video which says the crystal is almost all inductance, like several henries.
Then the series capacitance makes the inductor impossible to use as just an inductor.:(
and the 430 KHz crystals are more than an inch in 2 dimensions.:eek:
 

Thread Starter

Wendy

Joined Mar 24, 2008
21,914
Questions:
  • Does that circuit really output a sinusoidal wave as it seems in the diagram?
  • Does it mean that the crystal has some capacitive component to it too, or is the sinusoid being produced by the piezoelectric properties in the crystal itself?
  • What would it take for that circuit to output a square wave (other than the addition of a comparator) ?
Avtually as Irecall Itwas nott. AllThe articles I've read showboth a zies and parallelLC circuit with a high Q.The wave form was not very pure/ As ateen I could not afford good test equipment
 
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